@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 {6239, title = {Fibroblast growth factor 23, the ankle-brachial index, and incident peripheral artery disease in the Cardiovascular Health Study.}, journal = {Atherosclerosis}, volume = {233}, year = {2014}, month = {2014 Mar}, pages = {91-6}, abstract = {

BACKGROUND: Fibroblast growth factor 23 (FGF23) has emerged as a novel risk factor for mortality and cardiovascular events. Its association with the ankle-brachial index (ABI) and clinical peripheral artery disease (PAD) is less known.

METHODS: Using data (N = 3143) from the Cardiovascular Health Study (CHS), a cohort of community dwelling adults >65 years of age, we analyzed the cross-sectional association of FGF23 with ABI and its association with incident clinical PAD events during 9.8 years of follow up using multinomial logistic regression and Cox proportional hazards models respectively.

RESULTS: The prevalence of cardiovascular disease (CVD) and traditional risk factors like diabetes, coronary artery disease, and heart failure increased across higher quartiles of FGF23. Compared to those with ABI of 1.1-1.4, FGF23 per doubling at baseline was associated with prevalent PAD (ABI < 0.9) although this association was attenuated after adjusting for CVD risk factors, and kidney function (OR 0.91, 95\% CI 0.76-1.08). FGF23 was not associated with high ABI (>1.4) (OR 1.06, 95\% CI 0.75-1.51). Higher FGF23 was associated with incidence of PAD events in unadjusted, demographic adjusted, and CVD risk factor adjusted models (HR 2.26, 95\% CI 1.28-3.98; highest versus lowest quartile). The addition of estimated glomerular filtration and urine albumin to creatinine ratio to the model however, attenuated these findings (HR 1.46, 95\% CI, 0.79-2.70).

CONCLUSIONS: In community dwelling older adults, FGF23 was not associated with baseline low or high ABI or incident PAD events after adjusting for confounding variables. These results suggest that FGF23 may primarily be associated with adverse cardiovascular outcomes through non atherosclerotic mechanisms.

}, keywords = {Aged, Ankle Brachial Index, Cardiovascular Diseases, Cross-Sectional Studies, Fibroblast Growth Factors, Humans, Incidence, Peripheral Arterial Disease, Risk Factors}, issn = {1879-1484}, doi = {10.1016/j.atherosclerosis.2013.12.015}, author = {Garimella, Pranav S and Ix, Joachim H and Katz, Ronit and Chonchol, Michel B and Kestenbaum, Bryan R and de Boer, Ian H and Siscovick, David S and Shastri, Shani and Hiramoto, Jade S and Shlipak, Michael G and Sarnak, Mark J} }