Serum ascorbic acid and cardiovascular disease prevalence in U.S. adults: the Third National Health and Nutrition Examination Survey (NHANES III).

PURPOSE: To examine the relation between serum ascorbic acid concentration, which reflects dietary and supplement intake, and the prevalence of cardiovascular disease. METHODS: We analyzed data from 7658 men and women enrolled in the Third National Health and Nutrition Examination Survey (NHANES III). We calculated odds ratios and 95% confidence intervals (CI) to estimate the relative prevalence of cardiovascular disease, defined as self-reported angina, myocardial infarction, or stroke. Because we detected an interaction between serum ascorbic acid concentration and alcohol intake, we performed analyses stratified by drinking status. RESULTS: Among participants who reported no alcohol consumption, serum ascorbic acid concentrations were not independently associated with cardiovascular disease prevalence. Among participants who consumed alcohol, serum ascorbic acid concentrations consistent with tissue saturation (1.0-3.0 mg/dl) were associated with a decreased prevalence of angina (multivariate odds ratio (OR): 0.48; 95% CI: 0.23% to 1.03; p for trend = 0.06), but were not significantly associated with myocardial infarction or stroke prevalence. CONCLUSIONS: These results suggest the possibility of a biologic interaction between ascorbic acid and alcohol and that higher intakes of ascorbic acid may be associated with a decreased risk of angina among drinkers.