Kidney dysfunction and fatal cardiovascular disease--an association independent of atherosclerotic events: results from the Health, Aging, and Body Composition (Health ABC) study.

BACKGROUND: Impaired kidney function has been associated with increased risk for death, myocardial infarction, stroke, and heart failure in high-risk populations. We evaluated whether impaired kidney function predicted risk of fatal cardiovascular disease independent of prevalent and incident cardiovascular events. METHODS: The Health, Aging, and Body Composition study is a cohort of well-functioning, elderly participants aged 70 to 79 years at entry. We measured serum cystatin C and creatinine from baseline plasma samples of 3044 participants and followed them over 6 years, examining the associations among kidney function, cardiovascular death, and incident cardiovascular events. Cystatin C was categorized as low (< 0.84 mg/L), medium (0.84-1.18 mg/L), or high (> or = 1.19 mg/L); serum creatinine (cutoff value of > or = 1.3 in women and > or = 1.5 in men) and estimated glomerular filtration rate (eGFR; greater and less than 60 mL/min per 1.73 m2) were dichotomized. RESULTS: During follow-up, 242 cardiovascular deaths occurred, of which 69 were in participants without prior cardiovascular events; 294 incident cardiovascular events occurred including 135 myocardial infarctions and 163 strokes. Higher cystatin C concentrations were significantly associated with cardiovascular death (adjusted hazard ratio [HR] 1.70, 95% confidence interval [CI] 1.05-2.76 for the medium cystatin C group; and HR 2.24, 95% CI 1.30-3.86 for the high cystatin C group, relative to the low cystatin C group). The point estimate was of greater magnitude in the analysis that excluded prevalent cardiovascular disease (adjusted HR 2.68, 95% CI 0.94-7.70 for the medium cystatin C group; and HR 4.91, 95% CI, 1.55-15.54 for the high cystatin C group). Elevated creatinine levels (adjusted HR 1.54, 95% CI 1.02-2.33, and HR 2.28, 95% CI 1.10-4.73 among participants without a history of cardiovascular disease) were also associated with cardiovascular death. No significant association was found between low eGFR and cardiovascular death. In addition, cystatin C, low eGFR, or elevated creatinine levels were not associated with other cardiovascular events. CONCLUSION: Impaired kidney function is a strong predictor of cardiovascular death, particularly among participants without prior history of cardiovascular disease.

Prevalence and correlates of cardiovascular risk factors in South Asians: population-based data from two California surveys.

OBJECTIVE: Few population-based studies report cardiovascular disease (CVD) risk factor prevalence for South Asians in the United States. We examined CVD risk for South Asians in California. DESIGN/SETTING/PARTICIPANTS: We used data from two population-based surveys with South Asian participants in California, the California Health Interview Survey (CHIS) and the Cardiovascular Health among Asian Indian (CHAI) survey. The CHIS 2001 was conducted in English; 769 South Asians aged 25-83 years participated as one of many ethnic groups. The CHAI survey was population-based but focused on ethnicity-specific characteristics in 304 South Asians aged 25-80 years in English and Punjabi in 2001-2002. MAIN OUTCOME MEASURES: A CVD risk score included smoking, hypertension, hypercholesterolemia, diabetes, myocardial infarction, and angina. Separate logistic regression models examined the association of sociodemographics, lifestyle, medical risk, acculturation, and "any CVD risk." RESULTS: In CHAI, hypertension (20%), hypercholesterolemia (24%), and diabetes (10%) were high; smoking was low (12%). In CHIS, prevalence of these conditions was lower, except smoking (21%). Approximately 35% of participants in each survey had any CVD risk. Male sex, age, higher body mass index, education less than a bachelor's degree, and alcohol use were associated with CVD risk in both studies. The CHAI subjects interviewed in English had higher odds of any CVD risk than those interviewed in Punjabi (odds ratio 10.3, 95% confidence interval 2.9-36.7). CONCLUSIONS: Data from multiple sources add crucial information about heterogeneity of risk within ethnic populations. South Asians in the CHIS had higher rates of smoking, but lower CVD risk scores than participants in the CHAI study. In CHAI, English language use was associated with increased CVD risk score. Additional research should examine if acculturation increases CVD risk.