DIETARY ANTIOXIDANTS AND CAROTID-ARTERY WALL THICKNESS - THE ARIC STUDY

Background Evidence that dietary antioxidants may prevent atherosclerotic disease is growing. The relationship between the intake of dietary and supplemental vitamin C, alpha-tocopherol, and provitamin A carotenoids and average carotid artery wall thickness was studied in 6318 female and 4989 male participants 45 to 64 years old in the Atherosclerosis Risk in Communities Study. Methods and Results Intake was assessed by use of a 66-item semiquantitative food-frequency questionnaire. Carotid artery intima-media wall thickness was measured as an indicator of atherosclerosis at multiple sites with B-mode ultrasound. Among men and women >55 years old who had not recently begun a special diet, there was a significant inverse relationship between vitamin C intake and average artery wall thickness adjusted for age, body mass index, fasting serum glucose, systolic and diastolic blood pressures, HDL and LDL cholesterol, total caloric intake, cigarette use, race, and education (test for linear trend across quintiles of intake, P=.019 for women and P=.035 for men). An inverse relationship was also seen between wall thickness and alpha-tocopherol intake but was significant only in women (test for linear trend, P=.033 for women and P=.13 for men). There was a significant inverse association between carotene intake and wall thickness in older men (test for linear trend, P=.015), but the association weakened after adjustment for potential confounders. No significant relationships were seen in participants <55 years old. Conclusions These data provide limited support for the hypothesis that dietary vitamin C and alpha-tocopherol may protect against atherosclerotic disease, especially in individuals >55 years old.