@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 {1099, title = {Multiple loci associated with indices of renal function and chronic kidney disease.}, journal = {Nat Genet}, volume = {41}, year = {2009}, month = {2009 Jun}, pages = {712-7}, abstract = {

Chronic kidney disease (CKD) has a heritable component and is an important global public health problem because of its high prevalence and morbidity. We conducted genome-wide association studies (GWAS) to identify susceptibility loci for glomerular filtration rate, estimated by serum creatinine (eGFRcrea) and cystatin C (eGFRcys), and CKD (eGFRcrea < 60 ml/min/1.73 m(2)) in European-ancestry participants of four population-based cohorts (ARIC, CHS, FHS, RS; n = 19,877; 2,388 CKD cases), and tested for replication in 21,466 participants (1,932 CKD cases). We identified significant SNP associations (P < 5 {\texttimes} 10(-8)) with CKD at the UMOD locus, with eGFRcrea at UMOD, SHROOM3 and GATM-SPATA5L1, and with eGFRcys at CST and STC1. UMOD encodes the most common protein in human urine, Tamm-Horsfall protein, and rare mutations in UMOD cause mendelian forms of kidney disease. Our findings provide new insights into CKD pathogenesis and underscore the importance of common genetic variants influencing renal function and disease.

}, keywords = {Chromosome Mapping, Cohort Studies, Genetic Variation, Genome-Wide Association Study, Glomerular Filtration Rate, Humans, Kidney, Kidney Failure, Chronic, Meta-Analysis as Topic, Mucoproteins, Netherlands, Polymorphism, Single Nucleotide, Prevalence, Uromodulin}, issn = {1546-1718}, doi = {10.1038/ng.377}, author = {K{\"o}ttgen, Anna and Glazer, Nicole L and Dehghan, Abbas and Hwang, Shih-Jen and Katz, Ronit and Li, Man and Yang, Qiong and Gudnason, Vilmundur and Launer, Lenore J and Harris, Tamara B and Smith, Albert V and Arking, Dan E and Astor, Brad C and Boerwinkle, Eric and Ehret, Georg B and Ruczinski, Ingo and Scharpf, Robert B and Chen, Yii-Der Ida and de Boer, Ian H and Haritunians, Talin and Lumley, Thomas and Sarnak, Mark and Siscovick, David and Benjamin, Emelia J and Levy, Daniel and Upadhyay, Ashish and Aulchenko, Yurii S and Hofman, Albert and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and van Duijn, Cornelia M and Chasman, Daniel I and Par{\'e}, Guillaume and Ridker, Paul M and Kao, W H Linda and Witteman, Jacqueline C and Coresh, Josef and Shlipak, Michael G and Fox, Caroline 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 {1183, title = {New loci associated with kidney function and chronic kidney disease.}, journal = {Nat Genet}, volume = {42}, year = {2010}, month = {2010 May}, pages = {376-84}, abstract = {

Chronic kidney disease (CKD) is a significant public health problem, and recent genetic studies have identified common CKD susceptibility variants. The CKDGen consortium performed a meta-analysis of genome-wide association data in 67,093 individuals of European ancestry from 20 predominantly population-based studies in order to identify new susceptibility loci for reduced renal function as estimated by serum creatinine (eGFRcrea), serum cystatin c (eGFRcys) and CKD (eGFRcrea < 60 ml/min/1.73 m(2); n = 5,807 individuals with CKD (cases)). Follow-up of the 23 new genome-wide-significant loci (P < 5 x 10(-8)) in 22,982 replication samples identified 13 new loci affecting renal function and CKD (in or near LASS2, GCKR, ALMS1, TFDP2, DAB2, SLC34A1, VEGFA, PRKAG2, PIP5K1B, ATXN2, DACH1, UBE2Q2 and SLC7A9) and 7 loci suspected to affect creatinine production and secretion (CPS1, SLC22A2, TMEM60, WDR37, SLC6A13, WDR72 and BCAS3). These results further our understanding of the biologic mechanisms of kidney function by identifying loci that potentially influence nephrogenesis, podocyte function, angiogenesis, solute transport and metabolic functions of the kidney.

}, keywords = {Cohort Studies, Creatinine, Cystatin C, Diet, Europe, Genetic Markers, Genome-Wide Association Study, Glomerular Filtration Rate, Humans, Kidney, Kidney Failure, Chronic, Models, Genetic, Risk Factors}, issn = {1546-1718}, doi = {10.1038/ng.568}, author = {K{\"o}ttgen, Anna and Pattaro, Cristian and B{\"o}ger, Carsten A and Fuchsberger, Christian and Olden, Matthias and Glazer, Nicole L and Parsa, Afshin and Gao, Xiaoyi and Yang, Qiong and Smith, Albert V and O{\textquoteright}Connell, Jeffrey R and Li, Man and Schmidt, Helena and Tanaka, Toshiko and Isaacs, Aaron and Ketkar, Shamika and Hwang, Shih-Jen and Johnson, Andrew D and Dehghan, Abbas and Teumer, Alexander and Par{\'e}, Guillaume and Atkinson, Elizabeth J and Zeller, Tanja and Lohman, Kurt and Cornelis, Marilyn C and Probst-Hensch, Nicole M and Kronenberg, Florian and T{\"o}njes, Anke and Hayward, Caroline and Aspelund, Thor and Eiriksdottir, Gudny and Launer, Lenore J and Harris, Tamara B and Rampersaud, Evadnie and Mitchell, Braxton D and Arking, Dan E and Boerwinkle, Eric and Struchalin, Maksim and Cavalieri, Margherita and Singleton, Andrew and Giallauria, Francesco and Metter, Jeffrey and de Boer, Ian H and Haritunians, Talin and Lumley, Thomas and Siscovick, David and Psaty, Bruce M and Zillikens, M Carola and Oostra, Ben A and Feitosa, Mary and Province, Michael and de Andrade, Mariza and Turner, Stephen T and Schillert, Arne and Ziegler, Andreas and Wild, Philipp S and Schnabel, Renate B and Wilde, Sandra and Munzel, Thomas F and Leak, Tennille S and Illig, Thomas and Klopp, Norman and Meisinger, Christa and Wichmann, H-Erich and Koenig, Wolfgang and Zgaga, Lina and Zemunik, Tatijana and Kolcic, Ivana and Minelli, Cosetta and Hu, Frank B and Johansson, Asa and Igl, Wilmar and Zaboli, Ghazal and Wild, Sarah H and Wright, Alan F and Campbell, Harry and Ellinghaus, David and Schreiber, Stefan and Aulchenko, Yurii S and Felix, Janine F and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and Hofman, Albert and Imboden, Medea and Nitsch, Dorothea and Brandst{\"a}tter, Anita and Kollerits, Barbara and Kedenko, Lyudmyla and M{\"a}gi, Reedik and Stumvoll, Michael and Kovacs, Peter and Boban, Mladen and Campbell, Susan and Endlich, Karlhans and V{\"o}lzke, Henry and Kroemer, Heyo K and Nauck, Matthias and V{\"o}lker, Uwe and Polasek, Ozren and Vitart, Veronique and Badola, Sunita and Parker, Alexander N and Ridker, Paul M and Kardia, Sharon L R and Blankenberg, Stefan and Liu, Yongmei and Curhan, Gary C and Franke, Andre and Rochat, Thierry and Paulweber, Bernhard and Prokopenko, Inga and Wang, Wei and Gudnason, Vilmundur and Shuldiner, Alan R and Coresh, Josef and Schmidt, Reinhold and Ferrucci, Luigi and Shlipak, Michael G and van Duijn, Cornelia M and Borecki, Ingrid and Kr{\"a}mer, Bernhard K and Rudan, Igor and Gyllensten, Ulf and Wilson, James F and Witteman, Jacqueline C and Pramstaller, Peter P and Rettig, Rainer and Hastie, Nick and Chasman, Daniel I and Kao, W H and Heid, Iris M and Fox, Caroline 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 {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 {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 {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 {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 {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} }