Microalbuminuria and concentrations of antioxidants among us adults.

BACKGROUND: Microalbuminuria may increase the risk for cardiovascular disease. Increased oxidative stress, which may be important in the pathophysiological process of cardiovascular disease, occurs frequently in people with microalbuminuria and could depress their antioxidant concentrations, which then could contribute to end-organ damage associated with microalbuminuria. METHODS: We examined associations between microalbuminuria and circulating concentrations of vitamins A, C, and E and carotenoids in 9,575 US adults aged 20 years or older who participated in the Third National Health and Nutrition Examination Survey (1988 to 1994). RESULTS: After adjustment for age, sex, race or ethnicity, education, smoking status, cotinine concentration, physical activity, alcohol use, fruit and vegetable intake, vitamin or mineral use during the past 24 hours, body mass index, systolic blood pressure, and total cholesterol, triglyceride, glucose, insulin, and C-reactive protein concentrations, concentrations of beta-cryptoxanthin (odds ratio for quartile of highest concentration compared with quartile of lowest concentration, 0.56; 95% confidence interval, 0.38 to 0.82), lutein/zeaxanthin (odds ratio, 0.59; 95% confidence interval, 0.37 to 0.94), lycopene (odds ratio, 0.64; 95% confidence interval, 0.46 to 0.89), and total carotenoids (odds ratio, 0.54; 95% confidence interval, 0.38 to 0.75) were associated inversely with microalbuminuria. Vitamin C, vitamin E, and selenium concentrations were not significantly associated with microalbuminuria. CONCLUSION: People with microalbuminuria may have reduced concentrations of selected antioxidants. Additional research is needed to examine the relationships between microalbuminuria and antioxidant status, mechanisms for depletion of antioxidants, and possible benefits from increased intake of antioxidants through dietary change or the use of supplements in people with microalbuminuria.