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

Background Evidence that dietary antioxidants may prevent atherosclero tic disease is growing. The relationship between the intake of dietary and supplemental vitamin C, alpha-tocopherol, and provitamin A carote noids and average carotid artery wall thickness was studied in 6318 fe male and 4989 male participants 45 to 64 years old in the Atherosclero sis Risk in Communities Study. Methods and Results Intake was assessed by use of a 66-item semiquantitative food-frequency questionnaire. Ca rotid 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, th ere was a significant inverse relationship between vitamin C intake an d average artery wall thickness adjusted for age, body mass index, fas ting serum glucose, systolic and diastolic blood pressures, HDL and LD L cholesterol, total caloric intake, cigarette use, race, and educatio n (test for linear trend across quintiles of intake, P=.019 for women and P=.035 for men). An inverse relationship was also seen between wal l thickness and alpha-tocopherol intake but was significant only in wo men (test for linear trend, P=.033 for women and P=.13 for men). There was a significant inverse association between carotene intake and wal l thickness in older men (test for linear trend, P=.015), but the asso ciation weakened after adjustment for potential confounders. No signif icant relationships were seen in participants <55 years old. Conclusio ns These data provide limited support for the hypothesis that dietary vitamin C and alpha-tocopherol may protect against atherosclerotic dis ease, especially in individuals >55 years old.