@article {1130, title = {Association of chronic kidney disease with the spectrum of ankle brachial index the CHS (Cardiovascular Health Study).}, journal = {J Am Coll Cardiol}, volume = {54}, year = {2009}, month = {2009 Sep 22}, pages = {1176-84}, abstract = {

OBJECTIVES: This study sought to determine the association of chronic kidney disease (CKD) with high ankle brachial index (ABI) measurement and to compare its strength with that of CKD with a low ABI.

BACKGROUND: CKD is an important risk factor for cardiovascular disease (CVD) events. A high ABI, a marker of lower extremity arterial stiffness, is associated with CVD events and mortality. The association between CKD and high ABI is unknown.

METHODS: The CHS (Cardiovascular Health Study) enrolled community-living people >65 years of age and measured kidney function and ABI. Glomerular filtration rate (GFR) was estimated using equations that incorporated either cystatin C or creatinine, and CKD was defined by estimated GFR <60 ml/min/1.73 m(2). The ABI was categorized as low (<0.90), low-normal (0.90 to 1.09), normal (1.10 to 1.40), and high (>1.40 or incompressible). Multinomial logistic regression was used to evaluate the associations of CKD with ABI categories.

RESULTS: Among 4,513 participants, 23\% had CKD, 13\% had a low ABI, and 3\% had a high ABI. In models adjusted for age, sex, race, hypertension, diabetes, smoking, body mass index, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and C-reactive protein, cystatin C-based CKD was associated with both low ABI (relative risk [RR]: 2.0; 95\% confidence interval [CI]: 1.6 to 2.5; p <0.001) and high ABI (RR: 1.6; 95\% CI: 1.0 to 2.3; p = 0.03). Results were similar when CKD was defined by creatinine.

CONCLUSIONS: CKD is associated with both the high and the low extremes of ABI in community-living older people. Future studies should evaluate whether arterial stiffness is an important mechanism leading to CVD in people with CKD.

}, keywords = {Aged, Aged, 80 and over, Ankle Brachial Index, C-Reactive Protein, Cardiovascular Diseases, Chronic Disease, Cohort Studies, Cross-Sectional Studies, Female, Glomerular Filtration Rate, Humans, Kidney Diseases, Lipids, Male, Risk Factors}, issn = {1558-3597}, doi = {10.1016/j.jacc.2009.06.017}, author = {Ix, Joachim H and Katz, Ronit and de Boer, Ian H and Kestenbaum, Brian R and Allison, Matthew A and Siscovick, David S and Newman, Anne B and Sarnak, Mark J and Shlipak, Michael G and Criqui, Michael H} } @article {1110, title = {Cystatin C, albuminuria, and mortality among older adults with diabetes.}, journal = {Diabetes Care}, volume = {32}, year = {2009}, month = {2009 Oct}, pages = {1833-8}, abstract = {

OBJECTIVE: Albuminuria and impaired glomerular filtration rate (GFR) are each associated with poor health outcomes among individuals with diabetes. Joint associations of albuminuria and impaired GFR with mortality have not been comprehensively evaluated in this population.

RESEARCH DESIGN AND METHODS: This is a cohort study among Cardiovascular Health Study participants with diabetes, mean age 78 years. GFR was estimated using serum cystatin C and serum creatinine. Albumin-to-creatinine ratio (ACR) was measured in single-voided urine samples.

RESULTS: Of 691 participants, 378 died over 10 years of follow-up. Cystatin C-estimated GFR <60 ml/min per 1.73 m(2), creatinine-based estimated GFR <60 ml/min per 1.73 m(2), and urine ACR > or =30 mg/g were each associated with increased mortality risk with hazard ratios of 1.73 (95\% CI 1.37-2.18), 1.54 (1.21-1.97), and 1.73 (1.39-2.17), respectively, adjusting for age, sex, race, diabetes duration, hypoglycemic medications, hypertension, BMI, smoking, cholesterol, lipid-lowering medications, prevalent cardiovascular disease (CVD), and prevalent heart failure. Cystatin C-estimated GFR and urine ACR were additive in terms of mortality risk. Cystatin C-estimated GFR predicted mortality more strongly than creatinine-based estimated GFR.

CONCLUSIONS: Albuminuria and impaired GFR were independent, additive risk factors for mortality among older adults with diabetes. These findings support current recommendations to regularly assess both albuminuria and GFR in the clinical care of patients with diabetes; a focus on interventions to prevent or treat CVD in the presence of albuminuria, impaired GFR, or both; and further consideration of cystatin C use in clinical care.

}, keywords = {Aged, Aged, 80 and over, Albuminuria, Creatinine, Cystatin C, Diabetes Mellitus, Female, Glomerular Filtration Rate, Humans, Kidney Function Tests, Male, Risk Factors}, issn = {1935-5548}, doi = {10.2337/dc09-0191}, author = {de Boer, Ian H and Katz, Ronit and Cao, Jie J and Fried, Linda F and Kestenbaum, Bryan and Mukamal, Ken and Rifkin, Dena E and Sarnak, Mark J and Shlipak, Michael G and Siscovick, David S} } @article {1131, title = {Obesity and change in estimated GFR among older adults.}, journal = {Am J Kidney Dis}, volume = {54}, year = {2009}, month = {2009 Dec}, pages = {1043-51}, abstract = {

BACKGROUND: The prevalence of chronic kidney disease is growing most rapidly among older adults; however, determinants of impaired kidney function in this population are not well understood. Obesity assessed in midlife has been associated with chronic kidney disease.

STUDY DESIGN: Cohort study.

SETTING \& PARTICIPANTS: 4,295 participants in the community-based Cardiovascular Health Study, aged >or= 65 years.

PREDICTORS: Body mass index, waist circumference, and fat mass measured using bioelectrical impedance.

OUTCOME: Change in glomerular filtration rate (GFR) during 7 years of follow-up.

MEASUREMENTS: Longitudinal estimates of GFR calculated using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation.

RESULTS: Estimated GFR decreased by an average of 0.4 +/- 3.6 mL/min/1.73 m(2)/y, and rapid GFR loss (>3 mL/min/1.73 m(2)/y) occurred in 693 participants (16\%). Baseline body mass index, waist circumference, and fat mass were each associated with increased risk of rapid GFR loss: ORs, 1.19 (95\% CI, 1.09-1.30) per 5 kg/m(2), 1.25 (95\% CI, 1.16-1.36) per 12 cm, and 1.14 (95\% CI, 1.05-1.24) per 10 kg after adjustment for age, sex, race, and smoking. The magnitude of increased risk was larger for participants with estimated GFR < 60 mL/min/1.73 m(2) at baseline (P for interaction < 0.05). Associations were substantially attenuated by further adjustment for diabetes, hypertension, and C-reactive protein level. Obesity measurements were not associated with change in GFR estimated using serum cystatin C level.

LIMITATIONS: Few participants with advanced chronic kidney disease at baseline, no direct GFR measurements.

CONCLUSION: Obesity may be a modifiable risk factor for the development and progression of kidney disease in older adults.

}, keywords = {Aged, Aging, Body Composition, Body Mass Index, Chronic Disease, Cohort Studies, Creatinine, Cystatin C, Female, Glomerular Filtration Rate, Humans, Kidney, Kidney Diseases, Longitudinal Studies, Male, Obesity, Risk Factors}, issn = {1523-6838}, doi = {10.1053/j.ajkd.2009.07.018}, author = {de Boer, Ian H and Katz, Ronit and Fried, Linda F and Ix, Joachim H and Luchsinger, Jose and Sarnak, Mark J and Shlipak, Michael G and Siscovick, David S and Kestenbaum, Bryan} } @article {1149, title = {Albuminuria, impaired kidney function and cardiovascular outcomes or mortality in the elderly.}, journal = {Nephrol Dial Transplant}, volume = {25}, year = {2010}, month = {2010 May}, pages = {1560-7}, abstract = {

BACKGROUND: Kidney disease is a risk factor for mortality and cardiovascular disease in older adults, but the separate and combined effects of albuminuria and cystatin C, a novel marker of glomerular filtration, are not known.

METHODS: We examined associations of these markers with mortality and cardiovascular outcomes during a median follow-up of 8.3 years in 3291 older adults in the Cardiovascular Health Study. Kidney disease was assessed using urinary albumin/creatinine ratio (ACR), cystatin C and Modification of Diet in Renal Disease estimated glomerular filtration rate (eGFR). We defined subgroups based on presence of microalbuminuria (MA, ACR > 30 mg/g) and categories of normal kidney function (cystatin C < 1.0 mg/L and eGFR > 60 mL/min/1.73 m(2)); preclinical kidney disease (cystatin C level > 1.0 mg/l but eGFR > 60 mL/min/1.73 m(2)); and chronic kidney disease (CKD) (eGFR < 60 mL/min/1.73 m(2)). Cox proportional hazards models were used to examine associations between these six subgroups and all-cause or cardiovascular mortality, myocardial infarction and heart failure.

RESULTS: One thousand one hundred fifty (34.9\%) had normal kidney function (12.2\% with MA), 1518 (46.1\%) had preclinical kidney disease (17.9\% with MA) and 622 (18.9\%) had CKD (47\% with MA). After adjustment, the presence of either preclinical kidney disease or MA was associated with an over 50\% increase in mortality risk; the presence of both was associated with a 2.4-fold mortality risk. Those with CKD and MA were at highest risk, with a nearly 4-fold mortality risk.

CONCLUSION: Elevated cystatin C and albuminuria are common, identify different subsets of the older population, and are independent, graded risk factors for cardiovascular disease and mortality.

}, keywords = {Aged, Albuminuria, Cardiovascular Diseases, Creatinine, Cystatin C, Female, Glomerular Filtration Rate, Heart Failure, Humans, Male, Myocardial Infarction, Risk Factors}, issn = {1460-2385}, doi = {10.1093/ndt/gfp646}, author = {Rifkin, Dena E and Katz, Ronit and Chonchol, Michel and Fried, Linda F and Cao, Jie and de Boer, Ian H and Siscovick, David S and Shlipak, Michael G and Sarnak, Mark J} } @article {1186, title = {Alcohol consumption and kidney function decline in the elderly: alcohol and kidney disease.}, journal = {Nephrol Dial Transplant}, volume = {25}, year = {2010}, month = {2010 Oct}, pages = {3301-7}, abstract = {

BACKGROUND: Alcohol consumption appears to be protective for cardiovascular disease; however, its relationship with kidney disease is unclear.

METHODS: This prospective cohort study included 4343 subjects from the Cardiovascular Health Study, a longitudinal, community-based cohort of persons aged >=65 from four US communities. We used previously defined categories based on weekly alcohol consumption: none, former, <1 drink, 1-6 drinks, 7-13 drinks and >=14 drinks. Cystatin C was measured at baseline, year 3 and year 7; eligible subjects had at least two measures. Estimated GFR(cys) was calculated from cystatin C. The primary outcome was rapid kidney function as an annual estimated GFR (eGFR(cys)) loss >3 mL/min/1.73 m(2)/year.

RESULTS: Eight percent of the cohort reported former alcohol use and 52\% reported current alcohol consumption. During a mean follow-up of 5.6 years, 1075 (25\%) participants had rapid kidney function decline. In adjusted logistic regression models, there was no association between alcohol use and kidney function decline (odds ratio, 95\% confidence interval: none = reference; former = 1.18, 0.89-1.56; <1 drink = 1.20, 0.99-1.47; 1-6 = 1.18, 0.95-1.45; 7-13 = 1.10, 0.80-1.53; >14 = 0.89, 0.61-1.13). Results were similar with kidney function decline as a continuous outcome.

CONCLUSIONS: Our results suggest that moderate alcohol consumption has neither adverse nor beneficial effects on kidney function. Although clinicians will need to consider the potential deleterious effects associated with alcohol consumption, there does not appear to be a basis for recommending that older adults discontinue or initiate light to moderate alcohol consumption to protect against kidney disease.

}, keywords = {Aged, Aging, Alcohol Drinking, Cohort Studies, Cystatin C, Female, Glomerular Filtration Rate, Humans, Kidney, Kidney Diseases, Male, Prospective Studies}, issn = {1460-2385}, doi = {10.1093/ndt/gfq188}, author = {Menon, Vandana and Katz, Ronit and Mukamal, Kenneth and Kestenbaum, Bryan and de Boer, Ian H and Siscovick, David S and Sarnak, Mark J and Shlipak, Michael G} } @article {1210, title = {Association between adiposity in midlife and older age and risk of diabetes in older adults.}, journal = {JAMA}, volume = {303}, year = {2010}, month = {2010 Jun 23}, pages = {2504-12}, abstract = {

CONTEXT: Adiposity is a well-recognized risk factor for type 2 diabetes among young and middle-aged adults, but the relationship between body composition and type 2 diabetes is not well described among older adults.

OBJECTIVE: To examine the relationship between adiposity, changes in adiposity, and risk of incident type 2 diabetes in adults 65 years of age and older.

DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study (1989-2007) of 4193 men and women 65 years of age and older in the Cardiovascular Health Study. Measures of adiposity were derived from anthropometry and bioelectrical impedance data at baseline and anthropometry repeated 3 years later.

MAIN OUTCOME MEASURE: Incident diabetes was ascertained based on use of antidiabetic medication or a fasting glucose level of 126 mg/dL or greater.

RESULTS: Over median follow-up of 12.4 years (range, 0.9-17.8 years), 339 cases of incident diabetes were ascertained (7.1/1000 person-years). The adjusted hazard ratio (HR) (95\% confidence interval [CI]) of type 2 diabetes for participants in the highest quintile of baseline measures compared with those in the lowest was 4.3 (95\% CI, 2.9-6.5) for body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]), 3.0 (95\% CI, 2.0-4.3) for BMI at 50 years of age, 4.2 (95\% CI, 2.8-6.4) for weight, 4.0 (95\% CI, 2.6-6.0) for fat mass, 4.2 (95\% CI, 2.8-6.2) for waist circumference, 2.4 (95\% CI, 1.6-3.5) for waist-hip ratio, and 3.8 (95\% CI, 2.6-5.5) for waist-height ratio. However, when stratified by age, participants 75 years of age and older had HRs approximately half as large as those 65 to 74 years of age. Compared with weight-stable participants (+/-2 kg), those who gained the most weight from 50 years of age to baseline (> or = 9 kg), and from baseline to the third follow-up visit (> or = 6 kg), had HRs for type 2 diabetes of 2.8 (95\% CI, 1.9-4.3) and 2.0 (95\% CI, 1.1-3.7), respectively. Participants with a greater than 10-cm increase in waist size from baseline to the third follow-up visit had an HR of type 2 diabetes of 1.7 (95\% CI, 1.1-2.8) compared with those who gained or lost 2 cm or less.

CONCLUSION: Among older adults, overall and central adiposity, and weight gain during middle age and after the age of 65 years are associated with risk of diabetes.

}, keywords = {Adiposity, Age Factors, Aged, Body Mass Index, Diabetes Mellitus, Type 2, Female, Humans, Incidence, Male, Prospective Studies, Risk Factors, United States, Weight Gain}, issn = {1538-3598}, doi = {10.1001/jama.2010.843}, author = {Biggs, Mary L and Mukamal, Kenneth J and Luchsinger, Jos{\'e} A and Ix, Joachim H and Carnethon, Mercedes R and Newman, Anne B and de Boer, Ian H and Strotmeyer, Elsa S and Mozaffarian, Dariush and Siscovick, David S} } @article {1206, title = {Common genetic variants associate with serum phosphorus concentration.}, journal = {J Am Soc Nephrol}, volume = {21}, year = {2010}, month = {2010 Jul}, pages = {1223-32}, abstract = {

Phosphorus is an essential mineral that maintains cellular energy and mineralizes the skeleton. Because complex actions of ion transporters and regulatory hormones regulate serum phosphorus concentrations, genetic variation may determine interindividual variation in phosphorus metabolism. Here, we report a comprehensive genome-wide association study of serum phosphorus concentration. We evaluated 16,264 participants of European ancestry from the Cardiovascular Heath Study, Atherosclerosis Risk in Communities Study, Framingham Offspring Study, and the Rotterdam Study. We excluded participants with an estimated GFR <45 ml/min per 1.73 m(2) to focus on phosphorus metabolism under normal conditions. We imputed genotypes to approximately 2.5 million single-nucleotide polymorphisms in the HapMap and combined study-specific findings using meta-analysis. We tested top polymorphisms from discovery cohorts in a 5444-person replication sample. Polymorphisms in seven loci with minor allele frequencies 0.08 to 0.49 associate with serum phosphorus concentration (P = 3.5 x 10(-16) to 3.6 x 10(-7)). Three loci were near genes encoding the kidney-specific type IIa sodium phosphate co-transporter (SLC34A1), the calcium-sensing receptor (CASR), and fibroblast growth factor 23 (FGF23), proteins that contribute to phosphorus metabolism. We also identified genes encoding phosphatases, kinases, and phosphodiesterases that have yet-undetermined roles in phosphorus homeostasis. In the replication sample, five of seven top polymorphisms associate with serum phosphorous concentrations (P < 0.05 for each). In conclusion, common genetic variants associate with serum phosphorus in the general population. Further study of the loci identified in this study may help elucidate mechanisms of phosphorus regulation.

}, keywords = {Adult, Aged, European Continental Ancestry Group, Female, Fibroblast Growth Factors, Gene Frequency, Genetic Loci, Genetic Variation, Genome-Wide Association Study, Humans, Kidney, Male, Middle Aged, Phosphorus, Polymorphism, Single Nucleotide, Receptors, Calcium-Sensing, Sex Factors, Sodium-Phosphate Cotransporter Proteins, Type IIa}, issn = {1533-3450}, doi = {10.1681/ASN.2009111104}, author = {Kestenbaum, Bryan and Glazer, Nicole L and K{\"o}ttgen, Anna and Felix, Janine F and Hwang, Shih-Jen and Liu, Yongmei and Lohman, Kurt and Kritchevsky, Stephen B and Hausman, Dorothy B and Petersen, Ann-Kristin and Gieger, Christian and Ried, Janina S and Meitinger, Thomas and Strom, Tim M and Wichmann, H Erich and Campbell, Harry and Hayward, Caroline and Rudan, Igor and de Boer, Ian H and Psaty, Bruce M and Rice, Kenneth M and Chen, Yii-Der Ida and Li, Man and Arking, Dan E and Boerwinkle, Eric and Coresh, Josef and Yang, Qiong and Levy, Daniel and van Rooij, Frank J A and Dehghan, Abbas and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and Hofman, Albert and van Duijn, Cornelia M and Shlipak, Michael G and Kao, W H Linda and Witteman, Jacqueline C M and Siscovick, David S and Fox, Caroline S} } @article {1326, title = {Association of body mass index with peripheral arterial disease in older adults: the Cardiovascular Health Study.}, journal = {Am J Epidemiol}, volume = {174}, year = {2011}, month = {2011 Nov 01}, pages = {1036-43}, abstract = {

The authors hypothesized that the absence of cross-sectional associations of body mass index (BMI; weight (kg)/height (m)(2)) with peripheral arterial disease (PAD) in prior studies may reflect lower weight among persons who smoke or have poor health status. They conducted an observational study among 5,419 noninstitutionalized residents of 4 US communities aged >= 65 years at baseline (1989-1990 or 1992-1993). Ankle brachial index was measured, and participants reported their history of PAD procedures. Participants were followed longitudinally for adjudicated incident PAD events. At baseline, mean BMI was 26.6 (standard deviation, 4.6), and 776 participants (14\%) had prevalent PAD. During 13.2 (median) years of follow-up through June 30, 2007, 276 incident PAD events occurred. In cross-sectional analysis, each 5-unit increase in BMI was inversely associated with PAD (prevalence ratio (PR) = 0.92, 95\% confidence interval (CI): 0.85, 1.00). However, among persons in good health who had never smoked, the direction of association was opposite (PR = 1.20, 95\% CI: 0.94, 1.52). Similar results were observed between BMI calculated using weight at age 50 years and PAD prevalence (PR = 1.30, 95\% CI: 1.11, 1.51) and between BMI at baseline and incident PAD events occurring during follow-up (hazard ratio = 1.32, 95\% CI: 1.00, 1.76) among never smokers in good health. Greater BMI is associated with PAD in older persons who remain healthy and have never smoked. Normal weight maintenance may decrease PAD incidence and associated comorbidity in older age.

}, keywords = {Aged, Ankle Brachial Index, Body Mass Index, Cross-Sectional Studies, Health Status, Humans, Kaplan-Meier Estimate, Longitudinal Studies, Male, Obesity, Peripheral Arterial Disease, Prevalence, Sex Factors, Smoking, United States}, issn = {1476-6256}, doi = {10.1093/aje/kwr228}, author = {Ix, Joachim H and Biggs, Mary L and Kizer, Jorge R and Mukamal, Kenneth J and Djouss{\'e}, Luc and Zieman, Susan J and de Boer, Ian H and Nelson, Tracy L and Newman, Anne B and Criqui, Michael H and Siscovick, David S} } @article {1302, title = {Association of serum phosphate levels with aortic valve sclerosis and annular calcification: the cardiovascular health study.}, journal = {J Am Coll Cardiol}, volume = {58}, year = {2011}, month = {2011 Jul 12}, pages = {291-7}, abstract = {

OBJECTIVES: This study was conducted to evaluate mineral metabolism markers as potential risk factors for calcific aortic valve disease.

BACKGROUND: Mineral metabolism disturbances are common among older people and may contribute to cardiac valvular calcification. Associations of serum mineral metabolism markers with cardiac valvular calcification have not been evaluated in a well-characterized general population of older adults.

METHODS: We measured serum levels of phosphate, calcium, parathyroid hormone, and 25-hydroxyvitamin D in 1,938 Cardiovascular Health Study participants who were free of clinical cardiovascular disease and who underwent echocardiographic measurements of aortic valve sclerosis (AVS), mitral annular calcification (MAC), and aortic annular calcification (AAC). We used logistic regression models to estimate associations of mineral metabolism markers with AVS, MAC, and AAC after adjustment for relevant confounding variables, including kidney function.

RESULTS: The respective prevalences of AVS, MAC, and AAC were 54\%, 39\%, and 44\%. Each 0.5 mg/dl higher serum phosphate concentration was associated with greater adjusted odds of AVS (odds ratio [OR]: 1.17, 95\% confidence interval [CI]: 1.04 to 1.31, p = 0.01), MAC (OR: 1.12, 95\% CI: 1.00 to 1.26, p = 0.05), and AAC (OR: 1.12, 95\% CI: 0.99 to 1.25, p = 0.05). In contrast, serum calcium, parathyroid hormone, and 25-hydroxyvitamin D concentrations were not associated with aortic or mitral calcification.

CONCLUSIONS: Higher serum phosphate levels within the normal range were associated with valvular and annular calcification in a community-based cohort of older adults. Phosphate may be a novel risk factor for calcific aortic valve disease and warrants further study.

}, keywords = {Aged, Aortic Valve, Calcinosis, Calcium, Female, Heart Valve Diseases, Humans, Male, Mitral Valve, Parathyroid Hormone, Phosphates, Risk Factors, Sclerosis, Vitamin D}, issn = {1558-3597}, doi = {10.1016/j.jacc.2010.11.073}, author = {Linefsky, Jason P and O{\textquoteright}Brien, Kevin D and Katz, Ronit and de Boer, Ian H and Barasch, Eddy and Jenny, Nancy S and Siscovick, David S and Kestenbaum, Bryan} } @article {1339, title = {Fasting and post-glucose load measures of insulin resistance and risk of ischemic stroke in older adults.}, journal = {Stroke}, volume = {42}, year = {2011}, month = {2011 Dec}, pages = {3347-51}, abstract = {

BACKGROUND AND PURPOSE: Few studies have assessed post-glucose load measures of insulin resistance and ischemic stroke risk, and data are sparse for older adults. We investigated whether fasting and post-glucose load measures of insulin resistance were related to incident ischemic stroke in nondiabetic, older adults.

METHODS: Participants were men and women in the Cardiovascular Health Study, age 65+ years and without prevalent diabetes or stroke at baseline, followed for 17 years for incident ischemic stroke. The Gutt insulin sensitivity index was calculated from baseline body weight and from fasting and 2-hour postload insulin and glucose; a lower Gutt index indicates higher insulin resistance.

RESULTS: Analyses included 3442 participants (42\% men) with a mean age of 73 years. Incidence of ischemic stroke was 9.8 strokes per 1000 person-years. The relative risk (RR) for lowest quartile versus highest quartile of Gutt index was 1.64 (95\% CI, 1.24-2.16), adjusted for demographics and prevalent cardiovascular and kidney disease. Similarly, the adjusted RR for highest quartile versus lowest quartile of 2-hour glucose was 1.84 (95\% CI, 1.39-2.42). In contrast, the adjusted RR for highest quartile versus lowest quartile of fasting insulin was 1.10 (95\% CI, 0.84-1.46).

CONCLUSIONS: In nondiabetic, older adults, insulin resistance measured by Gutt index or 2-hour glucose, but not by fasting insulin, was associated with risk of incident ischemic stroke.

}, keywords = {Aged, Aged, 80 and over, Blood Glucose, Body Mass Index, Brain Ischemia, Fasting, Female, Humans, Incidence, Insulin Resistance, Male, Risk, Stroke}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.111.620773}, author = {Thacker, Evan L and Psaty, Bruce M and McKnight, Barbara and Heckbert, Susan R and Longstreth, W T and Mukamal, Kenneth J and Meigs, James B and de Boer, Ian H and Boyko, Edward J and Carnethon, Mercedes R and Kizer, Jorge R and Tracy, Russell P and Smith, Nicholas L and Siscovick, David S} } @article {1327, title = {Genetic association for renal traits among participants of African ancestry reveals new loci for renal function.}, journal = {PLoS Genet}, volume = {7}, year = {2011}, month = {2011 Sep}, pages = {e1002264}, abstract = {

Chronic kidney disease (CKD) is an increasing global public health concern, particularly among populations of African ancestry. We performed an interrogation of known renal loci, genome-wide association (GWA), and IBC candidate-gene SNP association analyses in African Americans from the CARe Renal Consortium. In up to 8,110 participants, we performed meta-analyses of GWA and IBC array data for estimated glomerular filtration rate (eGFR), CKD (eGFR <60 mL/min/1.73 m(2)), urinary albumin-to-creatinine ratio (UACR), and microalbuminuria (UACR >30 mg/g) and interrogated the 250 kb flanking region around 24 SNPs previously identified in European Ancestry renal GWAS analyses. Findings were replicated in up to 4,358 African Americans. To assess function, individually identified genes were knocked down in zebrafish embryos by morpholino antisense oligonucleotides. Expression of kidney-specific genes was assessed by in situ hybridization, and glomerular filtration was evaluated by dextran clearance. Overall, 23 of 24 previously identified SNPs had direction-consistent associations with eGFR in African Americans, 2 of which achieved nominal significance (UMOD, PIP5K1B). Interrogation of the flanking regions uncovered 24 new index SNPs in African Americans, 12 of which were replicated (UMOD, ANXA9, GCKR, TFDP2, DAB2, VEGFA, ATXN2, GATM, SLC22A2, TMEM60, SLC6A13, and BCAS3). In addition, we identified 3 suggestive loci at DOK6 (p-value = 5.3{\texttimes}10(-7)) and FNDC1 (p-value = 3.0{\texttimes}10(-7)) for UACR, and KCNQ1 with eGFR (p = 3.6{\texttimes}10(-6)). Morpholino knockdown of kcnq1 in the zebrafish resulted in abnormal kidney development and filtration capacity. We identified several SNPs in association with eGFR in African Ancestry individuals, as well as 3 suggestive loci for UACR and eGFR. Functional genetic studies support a role for kcnq1 in glomerular development in zebrafish.

}, keywords = {Adaptor Proteins, Vesicular Transport, Adult, African Continental Ancestry Group, Aged, Animals, Female, Gene Knockdown Techniques, Genetic Association Studies, Genetic Loci, Genome-Wide Association Study, Glomerular Filtration Rate, Humans, KCNQ1 Potassium Channel, Kidney, Kidney Failure, Chronic, Male, Middle Aged, Neoplasm Proteins, Phenotype, Polymorphism, Single Nucleotide, Zebrafish}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1002264}, author = {Liu, Ching-Ti and Garnaas, Maija K and Tin, Adrienne and K{\"o}ttgen, Anna and Franceschini, Nora and Peralta, Carmen A and de Boer, Ian H and Lu, Xiaoning and Atkinson, Elizabeth and Ding, Jingzhong and Nalls, Michael and Shriner, Daniel and Coresh, Josef and Kutlar, Abdullah and Bibbins-Domingo, Kirsten and Siscovick, David and Akylbekova, Ermeg and Wyatt, Sharon and Astor, Brad and Mychaleckjy, Josef and Li, Man and Reilly, Muredach P and Townsend, Raymond R and Adeyemo, Adebowale and Zonderman, Alan B and de Andrade, Mariza and Turner, Stephen T and Mosley, Thomas H and Harris, Tamara B and Rotimi, Charles N and Liu, Yongmei and Kardia, Sharon L R and Evans, Michele K and Shlipak, Michael G and Kramer, Holly and Flessner, Michael F and Dreisbach, Albert W and Goessling, Wolfram and Cupples, L Adrienne and Kao, W Linda and Fox, Caroline S} } @article {1254, title = {Measures of adiposity and future risk of ischemic stroke and coronary heart disease in older men and women.}, journal = {Am J Epidemiol}, volume = {173}, year = {2011}, month = {2011 Jan 01}, pages = {10-25}, abstract = {

The relation between measures of general and central adiposity and individual cardiovascular endpoints remains understudied in older adults. This study investigated the association of measures of body size and composition with incident ischemic stroke or coronary heart disease (1989-2007) in 3,754 community-dwelling US adults aged 65-100 years. Standardized anthropometry and bioelectric impedance measurements were obtained at baseline. Body mass index at age 50 years (BMI50) was calculated on the basis of recalled weight. Although only waist/hip ratio was significantly associated with ischemic stroke in quintile analysis in women, dichotomized body mass index (BMI) (>= 30 kg/m{\texttwosuperior}) was the only significant predictor in men. For coronary heart disease, there were significant positive adjusted associations for all adiposity measures, without interaction by sex. This was true for both quintiles and conventional cutpoints for obesity, although BMI-defined overweight (25-29.9 kg/m{\texttwosuperior} was significant at midlife but not at baseline. Strengths of association for extreme quintiles (quintile 5 vs. quintile 1) were broadly comparable, but the highest effect estimates were for waist/hip ratio (hazard ratio = 1.56, 95\% confidence interval: 1.25, 1.94) and BMI50 (hazard ratio = 1.71, 95\% confidence interval: 1.37, 2.14), both of which remained significant after adjustment for mediators, BMI, or each other. Whether these differences translate to better risk prediction will require meta-analytical approaches, as will determination of prognostic cutpoints.

}, keywords = {Adiposity, Age Factors, Aged, Aged, 80 and over, Brain Ischemia, Coronary Disease, Female, Humans, Incidence, Male, Middle Aged, Obesity, Prevalence, Retrospective Studies, Risk Factors, Sex Factors, United States}, issn = {1476-6256}, doi = {10.1093/aje/kwq311}, author = {Kizer, Jorge R and Biggs, Mary L and Ix, Joachim H and Mukamal, Kenneth J and Zieman, Susan J and de Boer, Ian H and Mozaffarian, Dariush and Barzilay, Joshua I and Strotmeyer, Elsa S and Luchsinger, Jos{\'e} A and Elkind, Mitchell S V and Longstreth, W T and Kuller, Lewis H and Siscovick, David S} } @article {1285, title = {Mineral metabolism markers and the long-term risk of hip fracture: the cardiovascular health study.}, journal = {J Clin Endocrinol Metab}, volume = {96}, year = {2011}, month = {2011 Jul}, pages = {2186-93}, abstract = {

CONTEXT: Disturbances in mineral metabolism are associated with lower bone mineral density and fracture; however, previous human studies have assessed individual mineral metabolism markers in isolation.

OBJECTIVE: We assessed serum concentrations of 25-hydroxyvitamin D (25-OHD), PTH, and bone-specific alkaline phosphatase (BAP) concentrations individually, and in combination, in association with the long-term risk of hip fracture among a general population of older adults.

DESIGN AND SETTING: We studied 2294 participants from the Cardiovascular Health Study (mean age 74 yr) who were ambulatory and free of hip fracture and known cardiovascular disease at baseline. We used proportional hazards models to evaluate associations of baseline serum 25-OHD, PTH, and BAP concentrations with the time to first hospitalized hip fracture.

RESULTS: During a median of 13 yr of follow-up, 242 participants (10.6\%) developed an incident hip fracture. Serum 25-OHD concentrations less than 15 ng/ml were associated with a 61\% greater adjusted risk of fracture (95\% confidence interval 12-132\% greater). In contrast, neither serum PTH nor BAP concentrations were significantly associated with fracture risk. The association of 25-OHD deficiency with hip fracture was not significantly altered by either PTH or BAP concentrations.

CONCLUSIONS: Serum concentrations of 25-OHD, but not PTH or BAP, are associated with long-term hip fracture risk among ambulatory older adults. These data suggest that 25-OHD is the most relevant mineral metabolism marker of fracture risk among older people.

}, keywords = {Aged, Aged, 80 and over, Alkaline Phosphatase, Biomarkers, Bone Density, Female, Hip Fractures, Humans, Male, Parathyroid Hormone, Risk, Vitamin D}, issn = {1945-7197}, doi = {10.1210/jc.2010-2878}, author = {Robinson-Cohen, Cassianne and Katz, Ronit and Hoofnagle, Andrew N and Cauley, Jane A and Furberg, Curt D and Robbins, John A and Chen, Zhao and Siscovick, David S and de Boer, Ian H and Kestenbaum, Bryan} } @article {1353, title = {Seasonal variation in 25-hydroxyvitamin D concentrations in the cardiovascular health study.}, journal = {Am J Epidemiol}, volume = {174}, year = {2011}, month = {2011 Dec 15}, pages = {1363-72}, abstract = {

Low circulating concentrations of 25-hydroxyvitamin D (25(OH)D) are associated with adverse health outcomes in diverse populations. However, 25(OH)D concentrations vary seasonally with varying exposure to sunlight, so single measurements may poorly reflect long-term 25(OH)D exposure. The authors investigated cyclical trends in average serum 25(OH)D concentrations among 2,298 individuals enrolled in the Cardiovascular Health Study of community-based older adults (1992-1993). A sinusoidal model closely approximated observed 25(OH)D concentrations and fit the data significantly better than did a mean model (P < 0.0001). The mean annual 25(OH)D concentration was 25.1 ng/mL (95\% confidence interval: 24.7, 25.5), and the mean peak-trough difference was 9.6 ng/mL (95\% confidence interval: 8.5, 10.7). Male sex, higher latitude of study site, and greater physical activity levels were associated with larger peak-trough difference in 25(OH)D concentration (each P < 0.05). Serum concentrations of intact parathyroid hormone and bone-specific alkaline phosphatase also varied in a sinusoidal fashion (P < 0.0001), inversely to 25(OH)D. In conclusion, serum 25(OH)D varies in a sinusoidal manner, with large seasonal differences relative to mean concentration and laboratory evidence of biologic sequelae. Single 25(OH)D measurements might not capture overall vitamin D status, and the extent of misclassification could vary by demographic and behavioral factors. Accounting for collection time may reduce bias in research studies and improve decision-making in clinical care.

}, keywords = {Aged, Biomarkers, Continental Population Groups, Exercise, Female, Humans, Male, Residence Characteristics, Seasons, Sex Factors, Vitamin D}, issn = {1476-6256}, doi = {10.1093/aje/kwr258}, author = {Shoben, Abigail B and Kestenbaum, Bryan and Levin, Gregory and Hoofnagle, Andrew N and Psaty, Bruce M and Siscovick, David S and de Boer, Ian H} } @article {1312, title = {Serum 25-hydroxyvitamin D and change in estimated glomerular filtration rate.}, journal = {Clin J Am Soc Nephrol}, volume = {6}, year = {2011}, month = {2011 Sep}, pages = {2141-9}, abstract = {

BACKGROUND AND OBJECTIVES: Mounting evidence suggests that 1,25-dihydroxyvitamin D prevents the progression of chronic kidney disease (CKD). It is not clear whether "nutritional" forms of vitamin D affect GFR.

DESIGN, SETTING, PARTICIPANTS, \& MEASUREMENTS: We tested whether serum 25-hydroxyvitamin D concentration (25(OH)D), a measure of total vitamin D intake from cutaneous synthesis and dietary consumption, is associated with loss of estimated GFR among 1705 older adults with predominantly normal baseline kidney function participating in the Cardiovascular Health Study. Baseline 25(OH)D was measured by HPLC-tandem mass spectrometry. GFR was estimated at baseline and 4 years later using the CKD-EPI formula, with rapid GFR loss defined as 12 ml/min per 1.73 m(2) or more over 4 years.

RESULTS: Rapid GFR loss was observed for 207 participants (12\%). Each 10 ng/ml lower 25(OH)D was associated with a 25\% greater risk of rapid GFR loss (95\% confidence interval [CI] 5\%, 49\%, P = 0.01), adjusting for potential confounding characteristics. Compared with 25(OH)D >=30 ng/ml, 25(OH)D concentrations 15 to 29 ng/ml and <15 ng/ml were associated with 29\% (95\% CI -13\%, 91\%) and 68\% (95\% CI 1\%, 177\%) greater adjusted risks of rapid GFR loss, respectively. Magnitudes of association were largest among participants with diabetes.

RESULTS: were similar evaluating a composite outcome of rapid GFR loss, end stage renal disease, and death. Conclusions Insufficient 25(OH)D may be a modifiable risk factor for early GFR loss. We recommend clinical trials to determine whether vitamin D supplementation prevents the development and progression of CKD.

}, keywords = {Aged, Female, Glomerular Filtration Rate, Humans, Kidney Diseases, Male, Prospective Studies, Vitamin D}, issn = {1555-905X}, doi = {10.2215/CJN.02640311}, author = {de Boer, Ian H and Katz, Ronit and Chonchol, Michel and Ix, Joachim H and Sarnak, Mark J and Shlipak, Michael G and Siscovick, David S and Kestenbaum, Bryan} } @article {1350, title = {Vitamin D, parathyroid hormone, and sudden cardiac death: results from the Cardiovascular Health Study.}, journal = {Hypertension}, volume = {58}, year = {2011}, month = {2011 Dec}, pages = {1021-8}, abstract = {

Recent studies have demonstrated greater risks of cardiovascular events and mortality among persons who have lower 25-hydroxyvitamin D (25-OHD) and higher parathyroid hormone (PTH) levels. We sought to evaluate the association between markers of mineral metabolism and sudden cardiac death (SCD) among the 2312 participants from the Cardiovascular Health Study who were free of clinical cardiovascular disease at baseline. We estimated associations of baseline 25-OHD and PTH concentrations individually and in combination with SCD using Cox proportional hazards models after adjustment for demographics, cardiovascular risk factors, and kidney function. During a median follow-up of 14 years, there were 73 adjudicated SCD events. The annual incidence of SCD was greater among subjects who had lower 25-OHD concentrations, 2 events per 1000 for 25-OHD >=20 ng/mL and 4 events per 1000 for 25-OHD <20 ng/mL. Similarly, SCD incidence was greater among subjects who had higher PTH concentrations, 2 events per 1000 for PTH <65 pg/mL and 4 events per 1000 for PTH >=65 pg/mL. Multivariate adjustment attenuated associations of 25-OHD and PTH with SCD. Finally, 267 participants (11.7\% of the cohort) had high PTH and low 25-OHD concentrations. This combination was associated with a >2-fold risk of SCD after adjustment (hazard ratio: 2.19 [95\% CI: 1.17-4.10]; P=0.017) compared with participants with normal levels of PTH and 25-OHD. The combination of lower 25-OHD and higher PTH concentrations appears to be associated independently with SCD risk among older adults without cardiovascular disease.

}, keywords = {Aged, Cardiovascular Diseases, Comorbidity, Death, Sudden, Cardiac, Diabetes Mellitus, Female, Follow-Up Studies, Humans, Hypertension, Incidence, Kidney, Male, Middle Aged, Minerals, Parathyroid Hormone, Proportional Hazards Models, Risk Factors, Socioeconomic Factors, United States, Vitamin D}, issn = {1524-4563}, doi = {10.1161/HYPERTENSIONAHA.111.179135}, author = {Deo, Rajat and Katz, Ronit and Shlipak, Michael G and Sotoodehnia, Nona and Psaty, Bruce M and Sarnak, Mark J and Fried, Linda F and Chonchol, Michel and de Boer, Ian H and Enquobahrie, Daniel and Siscovick, David and Kestenbaum, Bryan} } @article {5862, title = {Apolipoprotein E and kidney function in older adults.}, journal = {Clin Nephrol}, volume = {78}, year = {2012}, month = {2012 Sep}, pages = {174-80}, abstract = {

BACKGROUND: Previous studies suggest that the ε4 and ε2 alleles of apolipoprotein E (APOE) may be associated with decreased and increased risks of CKD, respectively, but there are limited data in older adults. We evaluated the associations of apolipoprotein E alleles with kidney function among older adults in the cardiovascular health study (CHS).

METHODS: Caucasian participants had APOE allelic analysis and serum creatinine and cystatin C measured at baseline (n = 3,844 for cross sectional analysis) and in follow up (n = 3,226 for longitudinal analysis). APOE variation was evaluated as an additive model with number of ε2, ε3 and ε4 alleles. GFR was estimated using the CKD epidemiology equation (eGFRcreat) and the cystatin C demographic equation (eGFRcys). The primary outcome was CKD defined by eGFR < 60 ml/min/1.73 m2. The secondary outcome was rapid progression defined by annual loss of eGFR > 3 ml/min/1.73 m2.

RESULTS: Mean eGFRcreat was 72 ml/min/1.73 m2 (25\% CKD). Compared with the ε3 allele, the APOE ε4 allele was associated with reduced risk of CKD by eGFRcreat: unadjusted odds ratio (OR) and 95\% confidence interval (CI) 0.79 (0.67 - 0.93) per allele, fully adjusted OR (95\% CI) 0.80 (0.68 - 0.96) per allele. Results were consistent using eGFRcys. There was no association of the ε2 allele with CKD or between the apolipoprotein E gene with rapid progression.

CONCLUSIONS: The apolipoprotein ε4 allele was associated with lower odds of CKD in elderly Caucasian individuals. Future research should confirm these findings in other races and explore mechanisms to explain these results.

}, keywords = {Aged, Aged, 80 and over, Alleles, Apolipoproteins E, Confidence Intervals, Creatinine, Cross-Sectional Studies, Cystatin C, Disease Progression, European Continental Ancestry Group, Female, Gene Frequency, Genotype, Glomerular Filtration Rate, Humans, Kidney, Male, Odds Ratio, Renal Insufficiency, Chronic, Risk Factors}, issn = {0301-0430}, author = {Seshasai, Rebecca Kurnik and Katz, Ronit and de Boer, Ian H and Siscovick, David and Shlipak, Michael G and Rifkin, Dena E and Sarnak, Mark J} } @article {1368, title = {Chronic kidney disease, insulin resistance, and incident diabetes in older adults.}, journal = {Clin J Am Soc Nephrol}, volume = {7}, year = {2012}, month = {2012 Apr}, pages = {588-94}, abstract = {

BACKGROUND AND OBJECTIVES: Insulin resistance is a complication of advanced CKD. Insulin resistance is less well characterized in earlier stages of CKD. The response of the pancreatic β cell, effects on glucose tolerance, and risk of diabetes are not clear.

DESIGN, SETTING, PARTICIPANTS, \& MEASUREMENTS: The Cardiovascular Health Study included 4680 adults without baseline diabetes. The Chronic Kidney Disease Epidemiology Collaboration creatinine equation was used to obtain the estimated GFR (eGFR). Insulin resistance was evaluated as fasting insulin concentration. The insulin sensitivity index, β cell function, and glucose tolerance were assessed by oral glucose tolerance testing. Incident diabetes was defined as fasting glucose >=126 mg/dl, nonfasting glucose >=200 mg/dl, or use of glucose-lowering medications.

RESULTS: Mean age was 72.5 years (range, 65-98 years). Mean eGFR was 72.2 (SD 17.1) ml/min per 1.73 m(2). After adjustment, each 10 ml/min per 1.73 m(2) lower eGFR was associated with a 2.2\% higher fasting insulin concentration (95\% confidence interval [CI], 1.4\%, 2.9\%; P<0.001) and a 1.1\% lower insulin sensitivity index (95\% CI, 0.03\%, 2.2\%; P=0.04). Surprisingly, eGFR was associated with an augmented β cell function index (P<0.001), lower 2-hour glucose concentration (P=0.002), and decreased risk of glucose intolerance (P=0.006). Over a median 12 years{\textquoteright} follow-up, 437 participants (9.3\%) developed diabetes. eGFR was not associated with the risk of incident diabetes.

CONCLUSIONS: Among older adults, lower eGFR was associated with insulin resistance. However, with lower eGFR, β cell function was appropriately augmented and risks of impaired glucose tolerance and incident diabetes were not increased.

}, keywords = {Age Factors, Aged, Aged, 80 and over, Biomarkers, Chronic Disease, Creatinine, Diabetes Mellitus, Female, Glomerular Filtration Rate, Glucose Tolerance Test, Health Surveys, Humans, Hypoglycemic Agents, Incidence, Insulin, Insulin Resistance, Insulin-Secreting Cells, Kidney, Kidney Diseases, Linear Models, Male, Proportional Hazards Models, Risk Assessment, Risk Factors, United States}, issn = {1555-905X}, doi = {10.2215/CJN.11861111}, author = {Pham, Hien and Robinson-Cohen, Cassianne and Biggs, Mary L and Ix, Joachim H and Mukamal, Kenneth J and Fried, Linda F and Kestenbaum, Bryan and Siscovick, David S and de Boer, Ian H} } @article {1392, title = {Fibroblast growth factor-23 and death, heart failure, and cardiovascular events in community-living individuals: CHS (Cardiovascular Health Study).}, journal = {J Am Coll Cardiol}, volume = {60}, year = {2012}, month = {2012 Jul 17}, pages = {200-7}, abstract = {

OBJECTIVES: This study sought to determine the association of fibroblast growth factor (FGF)-23 with death, heart failure (HF), and cardiovascular disease (CVD) in the general population, as well as the influence of chronic kidney disease (CKD) in this setting.

BACKGROUND: FGF-23 increases renal phosphorus excretion and inhibits vitamin D activation. In end-stage renal disease, high FGF-23 levels are associated with mortality. The association of FGF-23 with death, HF, and CVD in the general population, and the influence of CKD in this setting, are unknown.

METHODS: Plasma FGF-23 was measured in 3,107 community-living persons >= 65 years of age in 1996 and 1997, and participants were followed through 2008. HF and CVD events were adjudicated by a panel of experts. Associations of FGF-23 with each outcome were evaluated using Cox proportional hazards models, and we tested whether associations differed by CKD status.

RESULTS: Both lower estimated glomerular filtration rate and higher urine albumin to creatinine ratios were associated with high FGF-23 at baseline. During 10.5 years (median) follow-up, there were 1,730 deaths, 697 incident HF events, and 797 incident CVD events. Although high FGF-23 concentrations were associated with each outcome in combined analyses, the associations were consistently stronger for those with CKD (p interactions all <0.006). In the CKD group (n = 1,128), the highest FGF-23 quartile had adjusted hazards ratios (HR) of 1.87 (95\% confidence interval [CI]: 1.47 to 2.38) for all-cause death, 1.94 (95\% CI: 1.32 to 2.83) for incident HF, and 1.49 (95\% CI: 1.02 to 2.18) for incident CVD events compared with the lowest quartile. Corresponding HRs in those without CKD (n = 1,979) were 1.29 (95\% CI: 1.05 to 1.59), 1.37 (95\% CI: 0.99 to 1.89), and 1.07 (95\% CI: 0.79 to 1.45).

CONCLUSIONS: FGF-23, a hormone involved in phosphorous and vitamin D homeostasis, is independently associated with all-cause death and incident HF in community-living older persons. These associations appear stronger in persons with CKD.

}, keywords = {Aged, Aged, 80 and over, Biomarkers, Female, Fibroblast Growth Factors, Heart Failure, Humans, Kidney Function Tests, Male, Mortality, Renal Insufficiency, Chronic, United States}, issn = {1558-3597}, doi = {10.1016/j.jacc.2012.03.040}, author = {Ix, Joachim H and Katz, Ronit and Kestenbaum, Bryan R and de Boer, Ian H and Chonchol, Michel and Mukamal, Kenneth J and Rifkin, Dena and Siscovick, David S and Sarnak, Mark J and Shlipak, Michael G} } @article {1554, title = {Genetic variants and associations of 25-hydroxyvitamin D concentrations with major clinical outcomes.}, journal = {JAMA}, volume = {308}, year = {2012}, month = {2012 Nov 14}, pages = {1898-905}, abstract = {

CONTEXT: Lower serum 25-hydroxyvitamin D concentrations are associated with greater risks of many chronic diseases across large, prospective community-based studies. Substrate 25-hydroxyvitamin D must be converted to 1,25-dihydroxyvitamin D for full biological activity, and complex metabolic pathways suggest that interindividual variability in vitamin D metabolism may alter the clinical consequences of measured serum 25-hydroxyvitamin D.

OBJECTIVE: To investigate whether common variation within genes encoding the vitamin D-binding protein, megalin, cubilin, CYP27B1, CYP24A1, and the vitamin D receptor (VDR) modify associations of low 25-hydroxyvitamin D with major clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS: Examination of 141 single-nucleotide polymorphisms in a discovery cohort of 1514 white participants (who were recruited from 4 US regions) from the community-based Cardiovascular Health Study. Participants had serum 25-hydroxyvitamin D measurements in 1992-1993 and were followed up for a median of 11 years (through 2006). Replication meta-analyses were conducted across the independent, community-based US Health, Aging, and Body Composition (n = 922; follow-up: 1998-1999 through 2005), Italian Invecchiare in Chianti (n = 835; follow-up: 1998-2000 through 2006), and Swedish Uppsala Longitudinal Study of Adult Men (n = 970; follow-up: 1991-1995 through 2008) cohort studies.

MAIN OUTCOME MEASURE: Composite outcome of incident hip facture, myocardial infarction, cancer, and mortality over long-term follow-up.

RESULTS: Interactions between 5 single-nucleotide polymorphisms and low 25-hydroxyvitamin D concentration were identified in the discovery phase and 1 involving a variant in the VDR gene replicated in independent meta-analysis. Among Cardiovascular Health Study participants, low 25-hydroxyvitamin D concentration was associated with hazard ratios for risk of the composite outcome of 1.40 (95\% CI, 1.12-1.74) for those who had 1 minor allele at rs7968585 and 1.82 (95\% CI, 1.31-2.54) for those with 2 minor alleles at rs7968585. In contrast, there was no evidence of an association (estimated hazard ratio, 0.93 [95\% CI, 0.70-1.24]) among participants who had 0 minor alleles at this single-nucleotide polymorphism.

CONCLUSION: Known associations of low 25-hydroxyvitamin D with major health outcomes may vary according to common genetic differences in the vitamin D receptor.

}, keywords = {25-Hydroxyvitamin D3 1-alpha-Hydroxylase, Aged, Chronic Disease, Cohort Studies, Female, Genetic Variation, Genotype, Hip Fractures, Humans, Low Density Lipoprotein Receptor-Related Protein-2, Male, Meta-Analysis as Topic, Myocardial Infarction, Neoplasms, Polymorphism, Single Nucleotide, Receptors, Calcitriol, Receptors, Cell Surface, Risk, Steroid Hydroxylases, Vitamin D, Vitamin D3 24-Hydroxylase}, issn = {1538-3598}, doi = {10.1001/jama.2012.17304}, author = {Levin, Gregory P and Robinson-Cohen, Cassianne and de Boer, Ian H and Houston, Denise K and Lohman, Kurt and Liu, Yongmei and Kritchevsky, Stephen B and Cauley, Jane A and Tanaka, Toshiko and Ferrucci, Luigi and Bandinelli, Stefania and Patel, Kushang V and Hagstr{\"o}m, Emil and Micha{\"e}lsson, Karl and Melhus, H{\r a}kan and Wang, Thomas and Wolf, Myles and Psaty, Bruce M and Siscovick, David and Kestenbaum, Bryan} } @article {5860, title = {Hemoglobin A1c and arterial and ventricular stiffness in older adults.}, journal = {PLoS One}, volume = {7}, year = {2012}, month = {2012}, pages = {e47941}, abstract = {

OBJECTIVE: Arterial and ventricular stiffening are characteristics of diabetes and aging which confer significant morbidity and mortality; advanced glycation endproducts (AGE) are implicated in this stiffening pathophysiology. We examined the association between HbA(1c), an AGE, with arterial and ventricular stiffness measures in older individuals without diabetes.

RESEARCH DESIGN \& METHODS: Baseline HbA(1c) was measured in 830 participants free of diabetes defined by fasting glucose or medication use in the Cardiovascular Health Study, a population-based cohort study of adults aged >= 65 years. We performed cross-sectional analyses using baseline exam data including echocardiography, ankle and brachial blood pressure measurement, and carotid ultrasonography. We examined the adjusted associations between HbA(1c) and multiple arterial and ventricular stiffness measures by linear regression models and compared these results to the association of fasting glucose (FG) with like measures.

RESULTS: HbA(1c) was correlated with fasting and 2-hour postload glucose levels (r = 0.21; p<0.001 for both) and positively associated with greater body-mass index and black race. In adjusted models, HbA(1c) was not associated with any measure of arterial or ventricular stiffness, including pulse pressure (PP), carotid intima-media thickness, ankle-brachial index, end-arterial elastance, or left ventricular mass (LVM). FG levels were positively associated with systolic, diastolic and PP and LVM.

CONCLUSIONS: In this sample of older adults without diabetes, HbA(1c) was not associated with arterial or ventricular stiffness measures, whereas FG levels were. The role of AGE in arterial and ventricular stiffness in older adults may be better assessed using alternate AGE markers.

}, keywords = {Adult, African Continental Ancestry Group, Aged, Ankle Brachial Index, Arteries, Blood Glucose, Blood Pressure, Body Mass Index, Cross-Sectional Studies, Fasting, Female, Genetic Association Studies, Glycated Hemoglobin A, Glycation End Products, Advanced, Heart Ventricles, Humans, Male, Middle Aged, Ultrasonography, Vascular Stiffness}, issn = {1932-6203}, doi = {10.1371/journal.pone.0047941}, author = {Zieman, Susan J and Kamineni, Aruna and Ix, Joachim H and Barzilay, Joshua and Djouss{\'e}, Luc and Kizer, Jorge R and Biggs, Mary L and de Boer, Ian H and Chonchol, Michel and Gottdiener, John S and Selvin, Elizabeth and Newman, Anne B and Kuller, Lewis H and Siscovick, David S and Mukamal, Kenneth J} } @article {1370, title = {Insulin resistance and incident peripheral artery disease in the Cardiovascular Health Study.}, journal = {Vasc Med}, volume = {17}, year = {2012}, month = {2012 Apr}, pages = {85-93}, abstract = {

Type 2 diabetes is a risk factor for peripheral artery disease (PAD), and insulin resistance is a key feature of diabetes and pre-diabetes. No longitudinal epidemiological study has examined the relation between insulin resistance and PAD. Our study analyzed the association of quartiles of the homeostatic model of insulin resistance (HOMA-IR) and the development of PAD defined by two methods. PAD was first defined as the development of an abnormal ankle-brachial index (ABI) (dichotomous outcome) after 6 years of follow-up. PAD was alternatively defined as the development of clinical PAD (time-to-event analysis). The study samples included adults over the age of 65 years who were enrolled in the Cardiovascular Health Study, had fasting measurements of insulin and glucose, had ABI measurements, and were not receiving treatment for diabetes. Multivariable models were adjusted for potential confounders, including age, sex, field center and cohort, body mass index (BMI), smoking status, alcohol use, and exercise intensity. Additional models adjusted for potential mediators, including blood pressure, lipids, kidney function, and prevalent vascular disease. In the ABI analysis (n = 2108), multivariable adjusted models demonstrated a positive relation between HOMA-IR and incident PAD (odds ratio = 1.80 comparing the 4th versus 1st quartile of HOMA-IR, 95\% confidence interval [CI] 1.20-2.71). In the clinical PAD analysis (n = 4208), we found a similar relation (hazard ratio = 2.30 comparing the 4th versus 1st quartile of HOMA-IR, 95\% CI 1.15-4.58). As expected, further adjustment for potential mediators led to some attenuation of effect estimates. In conclusion, insulin resistance is associated with a higher risk of PAD in older adults.

}, keywords = {Aged, Ankle Brachial Index, Biomarkers, Blood Glucose, Diabetes Mellitus, Type 2, Diabetic Angiopathies, Fasting, Female, Health Surveys, Humans, Incidence, Insulin, Insulin Resistance, Logistic Models, Longitudinal Studies, Male, Odds Ratio, Peripheral Arterial Disease, Predictive Value of Tests, Proportional Hazards Models, Prospective Studies, Risk Assessment, Risk Factors, Time Factors, United States}, issn = {1477-0377}, doi = {10.1177/1358863X11436195}, author = {Britton, Kathryn A and Mukamal, Kenneth J and Ix, Joachim H and Siscovick, David S and Newman, Anne B and de Boer, Ian H and Thacker, Evan L and Biggs, Mary L and Gaziano, J Michael and Djouss{\'e}, Luc} } @article {1372, title = {Insulin resistance, cystatin C, and mortality among older adults.}, journal = {Diabetes Care}, volume = {35}, year = {2012}, month = {2012 Jun}, pages = {1355-60}, abstract = {

OBJECTIVE: Insulin resistance is a risk factor for cardiovascular and noncardiovascular diseases. Impaired kidney function is linked with insulin resistance and may affect relationships of insulin resistance with health outcomes.

RESEARCH DESIGN AND METHODS: We performed a cohort study of 3,138 Cardiovascular Health Study participants (age >= 65 years) without diabetes. Insulin sensitivity index (ISI) was calculated from fasting and 2-h postload insulin and glucose concentrations. Associations of ISI and fasting insulin concentration with all-cause mortality were tested using Cox proportional hazards models, adjusting for demographic variables, prevalent cardiovascular disease, lifestyle variables, waist circumference, and LDL cholesterol. Subsequent models were additionally adjusted for or stratified by glomerular filtration rate estimated using serum cystatin C (eGFR).

RESULTS: A total of 1,810 participants died during the 14.7-year median follow-up. Compared with the highest quartile of ISI, the lowest quartile (most insulin resistant) was associated with 21\% (95\% CI 6-41) and 11\% (-3 to 29) higher risks of death without and with adjustment for eGFR, respectively. Compared with the lowest quartile of fasting insulin concentration, the highest quartile was associated with 22\% (4-43) and 4\% (-12 to 22) higher risks of death without and with adjustment for eGFR, respectively. Similar attenuation by eGFR was observed when blood pressure, triglycerides, HDL cholesterol, and C-reactive protein were included in models.

CONCLUSIONS: Insulin resistance measured as ISI or fasting insulin concentration is associated with increased risk of death among older adults, adjusting for conventional confounding characteristics. Impaired kidney function may mediate or confound this relationship.

}, keywords = {Aged, Aged, 80 and over, Blood Glucose, Blood Pressure, C-Reactive Protein, Cardiovascular Diseases, Cholesterol, HDL, Cholesterol, LDL, Cohort Studies, Cystatin C, Fasting, Female, Glomerular Filtration Rate, Humans, Insulin Resistance, Life Style, Male, Mortality, Predictive Value of Tests, Proportional Hazards Models, Renal Insufficiency, Risk Factors, Triglycerides, Waist Circumference}, issn = {1935-5548}, doi = {10.2337/dc11-1657}, author = {de Boer, Ian H and Katz, Ronit and Chonchol, Michel B and Fried, Linda F and Ix, Joachim H and Kestenbaum, Bryan and Mukamal, Kenneth J and Peralta, Carmen A and Siscovick, David S} } @article {1322, title = {The risk of infection-related hospitalization with decreased kidney function.}, journal = {Am J Kidney Dis}, volume = {59}, year = {2012}, month = {2012 Mar}, pages = {356-63}, abstract = {

BACKGROUND: Moderate kidney disease may predispose to infection. We sought to determine whether decreased kidney function, estimated by serum cystatin C level, was associated with the risk of infection-related hospitalization in older individuals.

STUDY DESIGN: Cohort study.

SETTING \& PARTICIPANTS: 5,142 Cardiovascular Health Study (CHS) participants with measured serum creatinine and cystatin C and without estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m(2) at enrollment.

PREDICTOR: The primary exposure of interest was eGFR using serum cystatin C level (eGFR(SCysC)).

OUTCOME: Infection-related hospitalizations during a median follow-up of 11.5 years.

RESULTS: In adjusted analyses, eGFR(SCysC) categories of 60-89, 45-59, and 15-44 mL/min/1.73 m(2) were associated with 16\%, 37\%, and 64\% greater risk of all-cause infection-related hospitalization, respectively, compared with eGFR(SCysC) >=90 mL/min/1.73 m(2). When cause-specific infection was examined, eGFR(SCysC) of 15-44 mL/min/1.73 m(2) was associated with an 80\% greater risk of pulmonary and 160\% greater risk of genitourinary infection compared with eGFR(SCysC) >=90 mL/min/1.73 m(2).

LIMITATIONS: No measures of urinary protein, study limited to principal discharge diagnosis.

CONCLUSIONS: Lower kidney function, estimated using cystatin C level, was associated with a linear and graded risk of infection-related hospitalization. These findings highlight that even moderate degrees of decreased kidney function are associated with clinically significant higher risks of serious infection in older individuals.

}, keywords = {Aged, Cohort Studies, Female, Glomerular Filtration Rate, Hospitalization, Humans, Infection, Kidney, Male, Risk Factors}, issn = {1523-6838}, doi = {10.1053/j.ajkd.2011.07.012}, author = {Dalrymple, Lorien S and Katz, Ronit and Kestenbaum, Bryan and de Boer, Ian H and Fried, Linda and Sarnak, Mark J and Shlipak, Michael G} } @article {1384, title = {Serum 25-hydroxyvitamin D concentration and risk for major clinical disease events in a community-based population of older adults: a cohort study.}, journal = {Ann Intern Med}, volume = {156}, year = {2012}, month = {2012 May 01}, pages = {627-34}, abstract = {

BACKGROUND: Circulating concentrations of 25-hydroxyvitamin D [25-(OH)D] are used to define vitamin D deficiency. Current clinical 25-(OH)D targets based on associations with intermediate markers of bone metabolism may not reflect optimal levels for other chronic diseases and do not account for known seasonal variation in 25-(OH)D concentration.

OBJECTIVE: To evaluate the relationship of 25-(OH)D concentration with the incidence of major clinical disease events that are pathophysiologically relevant to vitamin D.

DESIGN: Cohort study.

SETTING: The Cardiovascular Health Study conducted in 4 U.S. communities. Data from 1992 to 2006 were included in this analysis.

PARTICIPANTS: 1621 white older adults.

MEASUREMENTS: Serum 25-(OH)D concentration (using a high-performance liquid chromatography-tandem mass spectrometry assay that conforms to National Institute of Standards and Technology reference standards) and associations with time to a composite outcome of incident hip fracture, myocardial infarction, cancer, or death.

RESULTS: Over a median 11-year follow-up, the composite outcome occurred in 1018 participants (63\%). Defining events included 137 hip fractures, 186 myocardial infarctions, 335 incidences of cancer, and 360 deaths. The association of low 25-(OH)D concentration with risk for the composite outcome varied by season (P = 0.057). A concentration lower than a season-specific Z score of -0.54 best discriminated risk for the composite outcome and was associated with a 24\% higher risk in adjusted analyses (95\% CI, 9\% to 42\%). Corresponding season-specific 25-(OH)D concentrations were 43, 50, 61, and 55 nmol/L (17, 20, 24, and 22 ng/mL) in winter, spring, summer, and autumn, respectively.

LIMITATION: The observational study was restricted to white participants.

CONCLUSION: Threshold concentrations of 25-(OH)D associated with increased risk for relevant clinical disease events center near 50 nmol/L (20 ng/mL). Season-specific targets for 25-(OH)D concentration may be more appropriate than static targets when evaluating health risk.

PRIMARY FUNDING SOURCE: National Institutes of Health.

}, keywords = {Aged, Cause of Death, Female, Follow-Up Studies, Hip Fractures, Humans, Male, Myocardial Infarction, Neoplasms, Proportional Hazards Models, Risk Assessment, Risk Factors, Seasons, United States, Vitamin D, Vitamin D Deficiency}, issn = {1539-3704}, doi = {10.7326/0003-4819-156-9-201205010-00004}, author = {de Boer, Ian H and Levin, Gregory and Robinson-Cohen, Cassianne and Biggs, Mary L and Hoofnagle, Andy N and Siscovick, David S and Kestenbaum, Bryan} } @article {6062, title = {Circulating 25-hydroxyvitamin D is associated with insulin resistance cross-sectionally but not longitudinally in older adults: The Cardiovascular Health Study.}, journal = {Metabolism}, volume = {62}, year = {2013}, month = {2013 Dec}, pages = {1788-94}, abstract = {

BACKGROUND: Despite extensive study, the role of vitamin D in insulin resistance and secretion remains unclear.

OBJECTIVE: To examine the cross-sectional and longitudinal relationships between 25-hydroxyvitamin D (25(OH)D) concentrations and indices of insulin resistance and secretion in older adults.

METHODS AND RESULTS: Among 2134 participants of the Cardiovascular Health Study who were free from cardiovascular disease, we measured serum 25(OH)D concentrations in samples collected in 1992-1993. We examined insulin resistance and secretion using Homeostasis Model Assessment (HOMA) estimates cross-sectionally and among 1469 participants who had repeated HOMA measures four years later (1996-1997). In cross-sectional analysis, each 10 ng/mL increment in 25(OH)D concentration was associated with a 0.09 lower adjusted HOMA-IR [95\% CI (-0.17, -0.02), p=0.01]. However, baseline 25(OH)D concentrations were not associated with change in HOMA-IR over 4 years of follow up (p=0.48). 25(OH)D concentrations were not associated with insulin secretion, as determined by HOMA-β, in either cross-sectional or longitudinal analysis.

CONCLUSIONS: Circulating 25(OH)D concentrations are associated with lower insulin resistance in cross-sectional but not longitudinal analyses. Whether this reflects residual confounding in cross-sectional analyses or the short-term nature of the relationship between vitamin D and insulin sensitivity will require trials with repeated measures of these factors.

}, keywords = {Adiposity, Aged, Anthropometry, Cardiovascular Diseases, Cross-Sectional Studies, Exercise, Female, Humans, Hydroxycholecalciferols, Inflammation, Insulin, Insulin Resistance, Longitudinal Studies, Male, Middle Aged, Obesity, Risk Factors, Surveys and Questionnaires}, issn = {1532-8600}, doi = {10.1016/j.metabol.2013.07.008}, author = {Danziger, John and Biggs, Mary L and Niemi, Matt and Ix, Joachim H and Kizer, Jorge R and Djouss{\'e}, Luc and de Boer, Ian H and Siscovick, David S and Kestenbaum, Bryan and Mukamal, Kenneth J} } @article {5996, title = {Fibroblast growth factor 23, bone mineral density, and risk of hip fracture among older adults: the cardiovascular health study.}, journal = {J Clin Endocrinol Metab}, volume = {98}, year = {2013}, month = {2013 Aug}, pages = {3323-31}, abstract = {

CONTEXT: Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that also inhibits calcitriol synthesis.

OBJECTIVE: Our objective was to evaluate the relationships of plasma FGF23 concentrations with bone mineral density (BMD) and hip fracture in community-dwelling older adults.

DESIGN AND SETTING: Linear regression and Cox proportional hazard models were used to examine the associations of plasma FGF23 concentrations with BMD and incident hip fracture, respectively. Analyses were also stratified by chronic kidney disease.

PARTICIPANTS: Participants included 2008 women and 1329 men >=65 years from the 1996 to 1997 Cardiovascular Health Study visit.

MAIN OUTCOME MEASURES: Dual x-ray absorptiometry measured total hip (TH) and lumbar spine (LS) BMD in 1291 participants. Hip fracture incidence was assessed prospectively through June 30, 2008 by hospitalization records in all participants.

RESULTS: Women had higher plasma FGF23 concentrations than men (75 [56-107] vs 66 [interquartile range = 52-92] relative units/mL; P < .001). After adjustment, higher FGF23 concentrations were associated with greater total hip and lumbar spine BMD in men only (β per doubling of FGF23 = 0.02, with 95\% confidence interval [CI] = 0.001-0.04 g/cm(2), and 0.03 with 95\% CI = 0.01-0.06 g/cm(2)). During 9.6 {\textpm} 5.1-11.0 years of follow-up, 328 hip fractures occurred. Higher FGF23 concentrations were not associated with hip fracture risk in women or men (adjusted hazard ratio = 0.95, with 95\% CI = 0.78-1.15, and 1.09 with 95\% CI = 0.82-1.46 per doubling of FGF23). Results did not differ by chronic kidney disease status (P > .4 for interactions).

CONCLUSIONS: In this large prospective cohort of community-dwelling older adults, higher FGF23 concentrations were weakly associated with greater lumbar spine and total hip BMD but not with hip fracture risk.

}, keywords = {Aged, Aged, 80 and over, Bone Density, Female, Fibroblast Growth Factors, Hip Fractures, Humans, Longitudinal Studies, Male, Middle Aged, Prospective Studies, Risk, Spinal Fractures}, issn = {1945-7197}, doi = {10.1210/jc.2013-1152}, author = {Jovanovich, Anna and B{\r u}zkov{\'a}, Petra and Chonchol, Michel and Robbins, John and Fink, Howard A and de Boer, Ian H and Kestenbaum, Bryan and Katz, Ronit and Carbone, Laura and Lee, Jennifer and Laughlin, Gail A and Mukamal, Kenneth J and Fried, Linda F and Shlipak, Michael G and Ix, Joachim H} } @article {7379, title = {Fibroblast growth factor 23, left ventricular mass, and left ventricular hypertrophy in community-dwelling older adults.}, journal = {Atherosclerosis}, volume = {231}, year = {2013}, month = {2013 Nov}, pages = {114-9}, abstract = {

OBJECTIVES: In chronic kidney disease (CKD), high FGF23 concentrations are associated with left ventricular hypertrophy (LVH), cardiovascular events, and death. The associations of FGF23 with left ventricular mass (LVM) and LVH in the general population and the influence of CKD remains uncertain.

METHODS: C-terminal plasma FGF23 concentrations were measured, and LVM and LVH evaluated by echocardiogram among 2255 individuals >=65 years in the Cardiovascular Health Study. Linear regression analysis adjusting for demographics, cardiovascular, and kidney related risk factors examined the associations of FGF23 concentrations with LVM. Analyses were stratified by CKD status and adjusted linear and logistic regression analysis explored the associations of FGF23 with LVM and LVH.

RESULTS: Among the entire cohort, higher FGF23 concentrations were associated with greater LVM in adjusted analyses (β = 6.71 [95\% CI 4.35-9.01] g per doubling of FGF23). 32\% (n = 624) had CKD (eGFR <60 mL/min/1.73 m(2) and/or urine albumin-to-creatinine ratio >30 mg/g). Associations were stronger among participants with CKD (p interaction = 0.006): LVM β = 9.71 [95\% CI 5.86-13.56] g per doubling of FGF23 compared to those without CKD (β = 3.44 [95\% CI 0.77, 6.11] g per doubling of FGF23). While there was no significant interaction between FGF23 and CKD for LVH (p interaction = 0.25), the OR (1.46 95\% CI [1.20-1.77]) in the CKD group was statistically significant and of larger magnitude than the OR for in the no CKD group (1.12 [95\% CI 0.97-1.48]).

CONCLUSION: In a large cohort of older community-dwelling adults, higher FGF23 concentrations were associated with greater LVM and LVH with stronger relationships in participants with CKD.

}, keywords = {Aged, Female, Fibroblast Growth Factors, Heart Ventricles, Humans, Hypertrophy, Left Ventricular, Longitudinal Studies, Male, Renal Insufficiency, Chronic, Risk Factors, Ultrasonography}, issn = {1879-1484}, doi = {10.1016/j.atherosclerosis.2013.09.002}, author = {Jovanovich, Anna and Ix, Joachim H and Gottdiener, John and McFann, Kim and Katz, Ronit and Kestenbaum, Bryan and de Boer, Ian H and Sarnak, Mark and Shlipak, Michael G and Mukamal, Kenneth J and Siscovick, David and Chonchol, Michel} } @article {1559, title = {Relation of vitamin D and parathyroid hormone to cardiac biomarkers and to left ventricular mass (from the Cardiovascular Health Study).}, journal = {Am J Cardiol}, volume = {111}, year = {2013}, month = {2013 Feb 01}, pages = {418-24}, abstract = {

Vitamin D and parathyroid hormone (PTH) may affect cardiovascular health in patients with kidney disease and in the general population. The aim of this study was to investigate associations of serum 25-hydroxyvitamin D (25(OH)D) and PTH concentrations with a comprehensive set of biochemical, electrocardiographic, and echocardiographic measurements of cardiac structure and function in the Cardiovascular Health Study. A total of 2,312 subjects who were free of cardiovascular disease at baseline were studied. Serum 25(OH)D and intact PTH concentrations were measured using mass spectrometry and a 2-site immunoassay. Outcomes were N-terminal pro-B-type natriuretic peptide, cardiac troponin T, electrocardiographic measures of conduction, and echocardiographic measures of left ventricular mass and diastolic dysfunction. At baseline, subjects had a mean age of 73.9 {\textpm} 4.9 years, 69.7\% were women, and 21\% had chronic kidney disease (glomerular filtration rate <60 ml/min). Mean 25(OH)D was 25.2 {\textpm} 10.2 ng/ml, and median PTH was 51 pg/ml (range 39 to 65). After adjustment, 25(OH)D was not associated with any of the biochemical, conduction, or echocardiographic outcomes. Serum PTH levels >=65 pg/ml were associated with greater N-terminal pro-B-type natriuretic peptide, cardiac troponin T, and left ventricular mass in patients with chronic kidney disease. The regression coefficients were: 120 pg/ml (95\% confidence interval 36.1 to 204), 5.2 pg/ml (95\% confidence interval 3.0 to 7.4), and 17 g (95\% confidence interval 6.2 to 27.8) (p <0.001). In subjects with normal kidney function, PTH was not associated with the outcomes. In conclusion, in older adults with chronic kidney disease, PTH excess is associated with higher N-terminal pro-B-type natriuretic peptide, cardiac troponin T, and left ventricular mass. These findings suggest a role for PTH in cardiovascular health and the prevention of cardiac diseases.

}, keywords = {Adult, Aged, Biomarkers, Cardiovascular Diseases, Echocardiography, Electrocardiography, Female, Follow-Up Studies, Heart Ventricles, Humans, Incidence, Male, Mass Spectrometry, Middle Aged, Parathyroid Hormone, Prospective Studies, United States, Vitamin D}, issn = {1879-1913}, doi = {10.1016/j.amjcard.2012.10.021}, author = {van Ballegooijen, Adriana J and Visser, Marjolein and Kestenbaum, Bryan and Siscovick, David S and de Boer, Ian H and Gottdiener, John S and deFilippi, Christopher R and Brouwer, Ingeborg A} } @article {6340, title = {Estimated GFR and circulating 24,25-dihydroxyvitamin D3 concentration: a participant-level analysis of 5 cohort studies and clinical trials.}, journal = {Am J Kidney Dis}, volume = {64}, year = {2014}, month = {2014 Aug}, pages = {187-97}, abstract = {

BACKGROUND: Decreased glomerular filtration rate (GFR) leads to reduced production of 1,25-dihydroxyvitamin D3 from 25-hydroxyvitamin D3 (25[OH]D3). Effects of low GFR on vitamin D catabolism are less well understood. We tested associations of estimated GFR (eGFR) with the circulating concentration of 24,25-dihydroxyvitamin D3 (24,25[OH]2D3), the most abundant product of 25(OH)D3 catabolism, across populations with a wide range of GFRs.

STUDY DESIGN: Cross-sectional study.

SETTING \& PARTICIPANTS: 9,596 participants in 5 cohort studies and clinical trials: the Diabetes Control and Complications Trial (N=1,193), Multi-Ethnic Study of Atherosclerosis (N=6,470), Cardiovascular Health Study (N=932), Seattle Kidney Study (N=289), and Hemodialysis Study (N=712).

PREDICTOR: eGFR.

OUTCOME: Circulating 24,25(OH)2D3 concentration.

MEASUREMENTS: GFR was estimated from serum creatinine using the Chronic Kidney Disease Epidemiology Collaboration equation. Vitamin D metabolites were measured by mass spectrometry.

RESULTS: Circulating 24,25(OH)2D3 concentration was correlated with circulating 25(OH)D3 concentration (Pearson r range, 0.64-0.88). This correlation was weaker with lower eGFRs. Moreover, the increment in 24,25(OH)2D3 concentration associated with higher 25(OH)D3 concentration (slope) was lower with lower eGFRs: 2.06 (95\% CI, 2.01-2.10), 1.77 (95\% CI, 1.74-1.81), 1.55 (95\% CI, 1.48-1.62), 1.17 (95\% CI, 1.05-1.29), 0.92 (95\% CI, 0.74-1.10), 0.61 (95\% CI, 0.22-1.00), and 0.37 (95\% CI, 0.35-0.39) ng/mL of 24,25(OH)2D3 per 10 ng/mL of 25(OH)D3 for eGFRs>=90, 60-89, 45-59, 30-44, 15-29, and <15 mL/min/1.73 m2 and end-stage renal disease treated with hemodialysis, respectively. As a result, at a 25(OH)D3 concentration of 20 ng/mL, mean 24,25(OH)2D3 concentrations were 2.92 (95\% CI, 2.87-2.96), 2.68 (95\% CI, 2.64-2.72), 2.35 (95\% CI, 2.26-2.45), 1.92 (95\% CI, 1.74-2.10), 1.69 (95\% CI, 1.43-1.95), 1.14 (95\% CI, 0.62-1.66), and 1.04 (95\% CI,1.02-1.07) ng/mL for each category, respectively. This interaction was independent of other relevant clinical characteristics. Race, diabetes, urine albumin excretion, and circulating parathyroid hormone and fibroblast growth factor 23 concentrations more modestly modified the association of 24,25(OH)2D3 with 25(OH)D3.

LIMITATIONS: Lack of direct pharmacokinetic measurements of vitamin D catabolism.

CONCLUSIONS: Lower eGFR is associated strongly with reduced vitamin D catabolism, as measured by circulating 24,25(OH)2D3 concentration.

}, keywords = {24,25-Dihydroxyvitamin D 3, Adult, Aged, Aged, 80 and over, Biomarkers, Cohort Studies, Cross-Sectional Studies, Diabetes Mellitus, Female, Glomerular Filtration Rate, Humans, Kidney Failure, Chronic, Male, Middle Aged, Observational Studies as Topic, Randomized Controlled Trials as Topic, Young Adult}, issn = {1523-6838}, doi = {10.1053/j.ajkd.2014.02.015}, author = {de Boer, Ian H and Sachs, Michael C and Chonchol, Michel and Himmelfarb, Jonathan and Hoofnagle, Andrew N and Ix, Joachim H and Kremsdorf, Robin A and Lin, Yvonne S and Mehrotra, Rajnish and Robinson-Cohen, Cassianne and Siscovick, David S and Steffes, Michael W and Thummel, Kenneth E and Tracy, Russell P and Wang, Zhican and Kestenbaum, Bryan} } @article {6399, title = {Fibroblast growth factor-23 and incident atrial fibrillation: the Multi-Ethnic Study of Atherosclerosis (MESA) and the Cardiovascular Health Study (CHS).}, journal = {Circulation}, volume = {130}, year = {2014}, month = {2014 Jul 22}, pages = {298-307}, abstract = {

BACKGROUND: Fibroblast growth factor-23 (FGF-23) is a hormone that promotes urinary phosphate excretion and regulates vitamin D metabolism. Circulating FGF-23 concentrations increase markedly in chronic kidney disease and are associated with increased risk of clinical cardiovascular events. FGF-23 may promote atrial fibrillation (AF) by inducing left ventricular hypertrophy and diastolic and left atrial dysfunction.

METHODS AND RESULTS: We tested the associations of circulating FGF-23 concentration with incident AF among 6398 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) and 1350 participants in the Cardiovascular Health Study (CHS), all free of clinical cardiovascular disease at baseline. Over a median of 7.7 and 8.0 years of follow-up, we observed 291 and 229 incident AF events in MESA and CHS, respectively. In multivariable Cox proportional hazards models, each 2-fold-higher FGF-23 concentration was associated with a 41\% higher risk of incident AF in MESA (hazard ratio, 1.41; 95\% confidence interval, 1.13-1.76; P=0.003) and a 30\% higher risk of incident AF in CHS (hazard ratio, 1.30; 95\% confidence interval, 1.05-1.61; P=0.016) after adjustment for potential confounding characteristics, including kidney disease. Serum phosphate concentration was significantly associated with incident AF in MESA (hazard ratio, 1.15 per 0.5 mg/dL; 95\% confidence interval, 1.02-1.31; P=0.023) but not CHS. In MESA, an association of low estimated glomerular filtration rate with incident AF was partially attenuated by adjustment for FGF-23.

CONCLUSION: Higher circulating FGF-23 concentration is associated with incident AF and may, in part, explain the link between chronic kidney disease and AF.

}, keywords = {Aged, Aged, 80 and over, Atrial Fibrillation, Comorbidity, Ethnic Groups, Female, Fibroblast Growth Factor 3, Follow-Up Studies, Glomerular Filtration Rate, Heart Failure, Humans, Hypertrophy, Left Ventricular, Male, Middle Aged, Phosphates, Proportional Hazards Models, Renal Insufficiency, Chronic, Risk Factors, United States, Ventricular Dysfunction, Left, Ventricular Remodeling, Vitamin D}, issn = {1524-4539}, doi = {10.1161/CIRCULATIONAHA.113.005499}, author = {Mathew, Jehu S and Sachs, Michael C and Katz, Ronit and Patton, Kristen K and Heckbert, Susan R and Hoofnagle, Andrew N and Alonso, Alvaro and Chonchol, Michel and Deo, Rajat and Ix, Joachim H and Siscovick, David S and Kestenbaum, Bryan and de Boer, Ian H} } @article {6308, title = {Fibroblast growth factor-23 and the long-term risk of hospital-associated AKI among community-dwelling older individuals.}, journal = {Clin J Am Soc Nephrol}, volume = {9}, year = {2014}, month = {2014 Feb}, pages = {239-46}, abstract = {

BACKGROUND AND OBJECTIVES: AKI occurs frequently in older persons. Elevated circulating fibroblast growth factor-23 (FGF-23), a known marker of impaired mineral metabolism, may also reflect tubular dysfunction and risk of AKI. This study evaluated FGF-23 as well as traditional markers of kidney disease, namely urine albumin-to-creatinine ratio (UACR) and creatinine-cystatin C estimated GFR (eGFRCrCyC), as risk factors for AKI in elderly individuals.

DESIGN, SETTING, PARTICIPANTS, \& MEASUREMENTS: Plasma FGF-23, UACR, and eGFRCrCyC were measured in 3241 community-dwelling elderly individuals in the Cardiovascular Health Study. Hospitalization for AKI was defined by International Classification of Diseases, Ninth Revision, Clinical Modification codes. Associations of each biomarker with AKI were evaluated using Cox proportional hazards models adjusted for demographics, cardiovascular risk factors, and biomarkers of kidney function.

RESULTS: The mean participant age was 78 years; 60\% of participants were women and 16\% were African American. The median (interquartile range) values of biomarkers were as follows: FGF-23, 70 RU/ml (53, 99); UACR, 8.88 mg/g (4.71, 20.47); and eGFRCrCyC, 71 ml/min per 1.73 m(2) (59, 83). Hospitalized AKI occurred in 119 participants over 10.0 years of median follow-up. In fully adjusted analyses, compared with the lowest quartiles, the highest quartiles of FGF-23 (>=100 RU/ml) and UACR (>=20.9 mg/g) were associated with AKI (FGF-23: hazard ratio [HR], 1.99; 95\% confidence interval [95\% CI], 1.04 to 3.80; and UACR: HR, 3.35; 95\% CI, 1.83 to 6.13). Compared with the highest quartile, the lowest quartile of eGFRCrCyC (<57 ml/min per 1.73 m(2)) was associated with AKI with an HR of 2.15 (95\% CI, 1.21 to 3.82).

CONCLUSIONS: FGF-23 adjusted for albuminuria, cardiovascular disease risk factors, and baseline eGFR is independently associated with a higher risk of AKI hospitalizations in community-dwelling elderly individuals. Further studies to understand the nature of this association are warranted.

}, keywords = {Acute Kidney Injury, Age Factors, Aged, Aged, 80 and over, Albuminuria, Biomarkers, Creatinine, Cystatin C, Female, Fibroblast Growth Factors, Glomerular Filtration Rate, Hospitalization, Humans, Independent Living, Kidney, Longitudinal Studies, Male, Prognosis, Proportional Hazards Models, Prospective Studies, Risk Factors, Time Factors}, issn = {1555-905X}, doi = {10.2215/CJN.05830513}, author = {Brown, Jeremiah R and Katz, Ronit and Ix, Joachim H and de Boer, Ian H and Siscovick, David S and Grams, Morgan E and Shlipak, Michael and Sarnak, Mark J} } @article {6659, title = {Development and validation of a model to predict 5-year risk of death without ESRD among older adults with CKD.}, journal = {Clin J Am Soc Nephrol}, volume = {10}, year = {2015}, month = {2015 Mar 6}, pages = {363-71}, abstract = {

BACKGROUND AND OBJECTIVES: CKD is associated with mortality. Accurate prediction tools for mortality may guide clinical decision-making, particularly among elderly persons with CKD.

DESIGN, SETTING, PARTICIPANTS, \& MEASUREMENTS: A prediction equation was developed for 5-year risk of mortality among participants with CKD in the Cardiovascular Health Study. Sixteen candidate predictor variables were explored, which included demographics, physical examination measures, comorbidity, medication use, and kidney function measures (eGFR calculated from serum creatinine and the CKD Epidemiology Collaboration equation and the urine albumin-to-creatinine ratio). Models were developed using Cox regression and evaluated using c statistics. A final parsimonious model was externally validated in an independent cohort of community-living elders with CKD in the Health, Aging, and Body Composition Study.

RESULTS: The development cohort included 828 participants who had a mean age of 80 ({\textpm}5.6) years and an eGFR of 47 ({\textpm}11) ml/min per 1.73 m(2), and median albumin-to-creatinine ratio of 13 (interquartile range 6-51) mg/g. The validation cohort included 789 participants who had a mean age of 74 ({\textpm}2.8) years and an eGFR of 50 ({\textpm}9) ml/min per 1.73 m(2), and median albumin-to-creatinine ratio of 13 (interquartile range 6-42) mg/g. The final model for 5-year mortality risk included age, sex, race, eGFR, urine albumin-to-creatinine ratio, smoking, diabetes mellitus, and history of heart failure and stroke (c statistic=0.72; 95\% confidence interval, 0.68 to 0.74). When a point-based system was assigned for each of nine variables in the equation, the estimated risk of death within 5 years ranged from 3.8\% among participants with the lowest scores to 83.6\% among participants with nine points. The model performed fair in external validation (c statistic=0.69; 95\% confidence interval, 0.64 to 0.74).

CONCLUSIONS: A simple prediction tool using nine readily available clinical variables can assist in predicting 5-year mortality risk in elderly patients with CKD, which may be useful in counseling patients and guiding clinical decision making.

}, keywords = {Age Factors, Aged, Aged, 80 and over, Albuminuria, Continental Population Groups, Creatinine, Diabetes Mellitus, Female, Glomerular Filtration Rate, Heart Failure, Humans, Male, Proportional Hazards Models, Regression Analysis, Renal Insufficiency, Chronic, Risk Factors, Sex Factors, Smoking, Stroke}, issn = {1555-905X}, doi = {10.2215/CJN.04650514}, author = {Bansal, Nisha and Katz, Ronit and de Boer, Ian H and Peralta, Carmen A and Fried, Linda F and Siscovick, David S and Rifkin, Dena E and Hirsch, Calvin and Cummings, Steven R and Harris, Tamara B and Kritchevsky, Stephen B and Sarnak, Mark J and Shlipak, Michael G and Ix, Joachim H} } @article {6662, title = {Fibroblast growth factor 23 and sudden versus non-sudden cardiac death: the Cardiovascular Health Study.}, journal = {Am J Kidney Dis}, volume = {66}, year = {2015}, month = {2015 Jul}, pages = {40-6}, abstract = {

BACKGROUND: Elevated fibroblast growth factor 23 (FGF-23) concentrations are associated with greater risk of cardiovascular events and mortality, especially among people with chronic kidney disease (CKD). Because individuals with CKD are at an increased risk of sudden cardiac death (SCD), we sought to understand whether FGF-23 level is a stronger risk factor for SCD versus non-SCD.

STUDY DESIGN: Cohort study.

SETTING \& PARTICIPANTS: 3,244 participants 65 years or older in the community-based Cardiovascular Health Study.

PREDICTOR: Plasma FGF-23 concentrations.

OUTCOMES: We assessed SCD and non-SCD in these analyses. SCD was adjudicated rigorously and was defined as a sudden pulseless condition of cardiac origin in a previously stable person occurring out of hospital or in the emergency department.

MEASUREMENTS: We estimated associations of baseline FGF-23 concentrations with SCD and non-SCD using Cox proportional hazards models after adjustment for demographics, cardiovascular risk factors, comorbid conditions, and kidney function. We also tested whether associations differed by CKD status.

RESULTS: During a median follow-up of 8.1 years, there were 118 adjudicated SCD and 570 non-SCD events. After multivariable adjustment for demographics, cardiovascular risk factors, comorbid conditions, and parameters of kidney function, higher FGF-23 concentrations were an independent risk factor for non-SCD (HR [per doubling], 1.17; 95\% CI, 1.06-1.30). However, elevated FGF-23 concentrations were not associated independently with SCD (HR [per doubling], 1.07; 95\% CI, 0.85-1.35). In stratified analysis by CKD status (36.5\% of cohort), doubling of FGF-23 concentrations was associated independently with non-SCD (adjusted HR, 1.26; 95\% CI, 1.10-1.45). A similar magnitude of association was observed between FGF-23 level and SCD in the CKD subgroup; however, it was not significant (HR, 1.20; 95\% CI, 0.89-1.62).

LIMITATIONS: Limited power to detect moderate-sized effects between FGF-23 level and SCD in both the primary and stratified analyses.

CONCLUSIONS: In this population-based study, FGF-23 level elevations were associated independently with non-SCD. Among individuals with CKD, the associations between FGF-23 level and SCD and non-SCD were similar.

}, keywords = {Aged, Aged, 80 and over, Biomarkers, Comorbidity, Death, Sudden, Cardiac, Electrocardiography, Female, Fibroblast Growth Factors, Follow-Up Studies, Heart Arrest, Heart Diseases, Humans, Kaplan-Meier Estimate, Male, Prospective Studies, Renal Insufficiency, Chronic, Risk Factors, Sympathetic Nervous System, United States}, issn = {1523-6838}, doi = {10.1053/j.ajkd.2014.10.025}, author = {Deo, Rajat and Katz, Ronit and de Boer, Ian H and Sotoodehnia, Nona and Kestenbaum, Bryan and Mukamal, Kenneth J and Chonchol, Michel and Sarnak, Mark J and Siscovick, David and Shlipak, Michael G and Ix, Joachim H} } @article {6400, title = {Potassium and glucose measures in older adults: the Cardiovascular Health Study.}, journal = {J Gerontol A Biol Sci Med Sci}, volume = {70}, year = {2015}, month = {2015 Feb}, pages = {255-61}, abstract = {

BACKGROUND: We sought to determine the impacts of serum and dietary potassium measures on glucose metabolism and diabetes risk in older adults.

METHODS: Among participants of the Cardiovascular Health Study, a community-based cohort of older American adults, we examined a) cross-sectional associations between potassium and measures of insulin sensitivity and secretion estimated from oral glucose tolerance tests and b) longitudinal associations of serum and dietary potassium with diabetes risk.

RESULTS: Among 4,754 participants aged >=65 years at baseline, there were 445 cases of incident diabetes during a median follow-up of 12 years. In multivariate models, baseline serum and dietary potassium were both associated with lower insulin sensitivity and greater insulin secretion. Compared with those with a serum potassium >=4.5 mEq/L, participants with a serum potassium <4.0mEq/L had an adjusted mean difference in Matsuda insulin sensitivity index of -0.18 (-0.39, 0.02). Compared with those in the highest quartile, participants in the lowest quartile of dietary potassium intake had a corresponding adjusted mean difference in Matsuda insulin sensitivity index of -0.61 (-0.94, -0.29). In multivariate models, neither serum nor dietary potassium intake was associated with long-term diabetes risk.

CONCLUSIONS: Although we did not identify serum and dietary potassium as risk factors for incident diabetes in older adults, results from cross-sectional analyses suggest that both may be associated with increased insulin resistance. This relationship with insulin resistance needs to be confirmed, and its importance on diabetes risk, cardiovascular risk, and conditions specific to older adults should be determined as well.

}, keywords = {Aged, Blood Glucose, Cohort Studies, Cross-Sectional Studies, Diabetes Mellitus, Female, Humans, Insulin, Insulin Resistance, Longitudinal Studies, Male, Multivariate Analysis, Potassium, Potassium, Dietary, Risk Factors, United States}, issn = {1758-535X}, doi = {10.1093/gerona/glu071}, author = {Chatterjee, Ranee and Biggs, Mary L and de Boer, Ian H and Brancati, Frederick L and Svetkey, Laura P and Barzilay, Joshua and Djouss{\'e}, Luc and Ix, Joachim H and Kizer, Jorge R and Siscovick, David S and Mozaffarian, Dariush and Edelman, David and Mukamal, Kenneth J} } @article {6997, title = {Associations of insulin resistance, inflammation and liver synthetic function with very low-density lipoprotein: The Cardiovascular Health Study.}, journal = {Metabolism}, volume = {65}, year = {2016}, month = {2016 Mar}, pages = {92-9}, abstract = {

INTRODUCTION: Production of very low-density lipoprotein (VLDL) is increased in states of metabolic syndrome, leading to hypertriglyceridemia. However, metabolic syndrome is often associated with non-alcoholic fatty liver disease, which leads to liver fibrosis and inflammation that may decrease VLDL production. In this study, we aim to determine the interactive impact on VLDL profiles from insulin resistance, impairment in liver synthetic function and inflammation.

METHODS: We examined cross-sectional associations of insulin sensitivity, inflammation, and liver synthetic function with VLDL particle (VLDL-P) concentration and size among 1,850 older adults in the Cardiovascular Health Study.

RESULTS: Indices for high insulin sensitivity and low liver synthetic function were associated with lower concentrations of VLDL-P. In addition, insulin resistance preferentially increased concentration of large VLDL and was associated with mean VLDL size. Indices for inflammation however demonstrated a nonlinear relationship with both VLDL-P concentration and VLDL size. When mutually adjusted, one standard deviation (SD) increment in Matsuda index and C-reactive protein (CRP) were associated with 4.9 nmol/L (-8.2 to -1.5, p=0.005) and 6.3 nmol/L (-11.0 to -1.6, p=0.009) lower VLDL-P concentration respectively. In contrast, one-SD increment in factor VII, a marker for liver synthetic function, was associated with 16.9 nmol/L (12.6-21.2, p<0.001) higher VLDL-P concentration. Furthermore, a one-SD increment in the Matsuda index was associated with 1.1 nm (-2.0 to -0.3, p=0.006) smaller mean VLDL size, whereas CRP and factor VII were not associated with VLDL size.

CONCLUSION: Insulin sensitivity, inflammation and markers for liver synthetic function differentially impact VLDL-P concentration and VLDL size. These results underscore the complex effects of insulin resistance and its complications on VLDL production.

}, keywords = {Aged, Aged, 80 and over, C-Reactive Protein, Cross-Sectional Studies, Factor VII, Female, Humans, Inflammation, Insulin Resistance, Lipoproteins, VLDL, Liver, Liver Function Tests, Male, Risk Factors, Socioeconomic Factors}, issn = {1532-8600}, doi = {10.1016/j.metabol.2015.10.017}, author = {Jiang, Z Gordon and de Boer, Ian H and Mackey, Rachel H and Jensen, Majken K and Lai, Michelle and Robson, Simon C and Tracy, Russell and Kuller, Lewis H and Mukamal, Kenneth J} } @article {6990, title = {Fibroblast Growth Factor-23 and Frailty in Elderly Community-Dwelling Individuals: The Cardiovascular Health Study.}, journal = {J Am Geriatr Soc}, volume = {64}, year = {2016}, month = {2016 Feb}, pages = {270-6}, abstract = {

OBJECTIVES: To evaluate whether fibroblast growth factor 23 (FGF-23) is related to frailty and to characterize the nature of their joint association with mortality.

DESIGN: Cross-sectional analysis for frailty and longitudinal cohort analysis for mortality.

SETTING: Cardiovascular Health Study.

PARTICIPANTS: Community-dwelling individuals (N = 2,977; mean age 77.9 {\textpm} 4.7, 40\% male, 83\% white).

MEASUREMENTS: The predictor was serum FGF-23 concentration (C-terminal enzyme-linked immunosorbent assay), and the outcomes were frailty status (determined according to frailty phenotype criteria of weight loss, weakness, exhaustion, slowness, and low physical activity) and mortality. Multinomial logistic regression was used to assess the cross-sectional association between FGF-23 and frailty and prefrailty, adjusting for demographic characteristics, cardiovascular disease and risk factors, and kidney markers. Proportional hazards Cox proportional hazards regression was used to assess the association between FGF-23, frailty, and all-cause mortality.

RESULTS: Mean estimated glomerular filtration rate (eGFR) was 64 {\textpm} 17 mL/min per 1.73 m(2) . Median FGF-23 was 70.3 RU/mL (interquartile range 53.4-99.2); 52\% were prefrail, and 13\% were frail. After multivariate adjustment, each doubling in FGF-23 concentration was associated with 38\% (95\% confidence interval (CI) = 17-62\%) higher odds of frailty than of nonfrailty and 16\% (95\% CI = 3-30\%) higher odds of prefrailty. FGF-23 (hazard ratio (HR) = 1.16, 95\% CI = 1.10-1.23) and frailty (HR = 1.82, 95\% CI = 1.57-2.12) were independently associated with mortality, but neither association was meaningfully attenuated when adjusted for the other.

CONCLUSION: In a large cohort of older adults, higher FGF-23 was independently associated with prevalent frailty and prefrailty. FGF-23 and frailty were independent and additive risk factors for mortality. FGF-23 may be a marker for functional outcomes.

}, keywords = {Aged, Anthropometry, Biomarkers, Cardiovascular Diseases, Cross-Sectional Studies, Enzyme-Linked Immunosorbent Assay, Female, Fibroblast Growth Factors, Frail Elderly, Glomerular Filtration Rate, Humans, Independent Living, Longitudinal Studies, Male, Phenotype, Risk Factors, Surveys and Questionnaires}, issn = {1532-5415}, doi = {10.1111/jgs.13951}, author = {Beben, Tomasz and Ix, Joachim H and Shlipak, Michael G and Sarnak, Mark J and Fried, Linda F and Hoofnagle, Andrew N and Chonchol, Michel and Kestenbaum, Bryan R and de Boer, Ian H and Rifkin, Dena E} } @article {8095, title = {Galectin-3 and Soluble ST2 and Kidney Function Decline in Older Adults: The Cardiovascular Health Study (CHS).}, journal = {Am J Kidney Dis}, volume = {67}, year = {2016}, month = {2016 06}, pages = {994-6}, keywords = {Aged, Cohort Studies, Creatinine, Cystatin C, Female, Galectin 3, Glomerular Filtration Rate, Humans, Interleukin-1 Receptor-Like 1 Protein, Logistic Models, Longitudinal Studies, Male, Prognosis, Renal Insufficiency, Chronic}, issn = {1523-6838}, doi = {10.1053/j.ajkd.2015.12.022}, author = {Bansal, Nisha and Katz, Ronit and Seliger, Stephen and DeFilippi, Christopher and Sarnak, Mark J and Delaney, Joseph A and Christenson, Robert and de Boer, Ian H and Kestenbaum, Bryan and Robinson-Cohen, Cassianne and Ix, Joachim H and Shlipak, Michael G} } @article {7601, title = {Fibroblast Growth Factor 23, Mineral Metabolism, and Adiposity in Normal Kidney Function.}, journal = {J Clin Endocrinol Metab}, volume = {102}, year = {2017}, month = {2017 Apr 01}, pages = {1387-1395}, abstract = {

Context: Obesity is associated with poor bone mineralization and quality. Fibroblast growth factor 23 (FGF23) plays an important role in skeletal physiology.

Objective: To test hypothesis that greater adiposity results in higher FGF23 levels among individuals with normal estimated glomerular filtration rate (eGFR).

Design, Setting, Participants: Cross-sectional analyses among participants with eGFR >=60 mL/min/1.73m2. We assessed the association between crude [body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR); n = 5610] and refined (abdominal adipose tissue area by computed tomography; n = 1313) measures of adiposity and FGF23 using multivariable linear regression.

Main Outcome Measure: Serum FGF23.

Results: FGF23 was higher across BMI categories (BMI <25: 37.7; BMI 25 to 29.99: 38.7; BMI 30 to 39.99: 39.8; BMI >=40: 40.9 pg/mL, unadjusted P trend < 0.0001). The association between BMI and FGF23 was independent of known confounders of FGF23 (adjusted β = +7.2\% higher FGF23 per 10 kg/m2; P < 0.0001). Similar results were observed using WC and WHR. Abdominal adipose tissue area was also independently associated with higher FGF23 (P < 0.01). Notably, the positive associations between FGF23 and adiposity were observed despite the fact that eGFR did not decline and serum phosphate levels did not increase with adiposity.

Conclusion: In a large cohort with normal kidney function, adiposity was associated with higher FGF23 levels independent of known confounders, including eGFR and phosphate. Further studies are needed to evaluate the causes of higher FGF23 in settings of greater adiposity and the potential impact on skeletal health.

}, keywords = {Adiposity, Aged, Aged, 80 and over, Cross-Sectional Studies, Female, Fibroblast Growth Factors, Glomerular Filtration Rate, Humans, Kidney, Male, Middle Aged, Minerals, Renal Insufficiency, Chronic, Risk Factors}, issn = {1945-7197}, doi = {10.1210/jc.2016-3563}, author = {Zaheer, Sarah and de Boer, Ian H and Allison, Matthew and Brown, Jenifer M and Psaty, Bruce M and Robinson-Cohen, Cassianne and Michos, Erin D and Ix, Joachim H and Kestenbaum, Bryan and Siscovick, David and Vaidya, Anand} } @article {8539, title = {Metabolic Clusters and Outcomes in Older Adults: The Cardiovascular Health Study.}, journal = {J Am Geriatr Soc}, volume = {66}, year = {2018}, month = {2018 02}, pages = {289-296}, abstract = {

BACKGROUND/OBJECTIVES: Few studies have the requisite phenotypic information to define metabolic patterns that may inform our understanding of the pathophysiology and consequences of diabetes in older adults. We sought to characterize clusters of older adults on the basis of shared metabolic features.

DESIGN: Population-based prospective cohort study.

SETTING: Four U.S. Cardiovascular Health Study field centers.

PARTICIPANTS: Individuals aged 65 and older taking no glucose-lowering agents (N~=~2,231).

MEASUREMENTS: K-means cluster analysis of 11 metabolic parameters (fasting and postload serum glucose and plasma insulin, fasting C-peptide, body mass index, C-reactive protein (CRP), estimated glomerular filtration rate (eGFR), albuminuria, carboxymethyl lysine (an advanced glycation end-product), procollagen III N-terminal propeptide (a fibrotic marker)) and their associations with incident cardiovascular disease, diabetes, disability, and mortality over 8 to 14.5~years of follow-up and with measures of subclinical cardiovascular disease.

RESULTS: A 6-cluster solution provided robust differentiation into distinct, identifiable clusters. Cluster A (n~=~739) had the lowest glucose and insulin and highest eGFR and the lowest rates of all outcomes. Cluster B (n~=~419) had high glucose and insulin and intermediate rates of most outcomes. Cluster C (n~=~118) had the highest insulin. Cluster D (n~=~129) had the highest glucose with much lower insulin. Cluster E (n~=~314) had the lowest eGFR and highest albuminuria. Cluster F (n~=~512) had the highest CRP. Rates of CVD, mortality, and subclinical atherosclerosis were highest in clusters C, D, and E and were similar to rates in participants with treated diabetes. Incidence of disability was highest in Cluster C.

CONCLUSION: Clustering according to metabolic parameters identifies distinct phenotypes that are strongly associated with clinical and functional outcomes, even at advanced age.

}, keywords = {Aged, Aged, 80 and over, Blood Glucose, C-Reactive Protein, Cardiovascular Diseases, Diabetes Mellitus, Female, Glomerular Filtration Rate, Humans, Incidence, Insulin, Longitudinal Studies, Male, Prospective Studies, Risk Factors, United States}, issn = {1532-5415}, doi = {10.1111/jgs.15205}, author = {Mukamal, Kenneth J and Siscovick, David S and de Boer, Ian H and Ix, Joachim H and Kizer, Jorge R and Djouss{\'e}, Luc and Fitzpatrick, Annette L and Tracy, Russell P and Boyko, Edward J and Kahn, Steven E and Arnold, Alice M} }