α-Tocopherol (vitamin E) and β-carotene supplementation does not affect the risk for large abdominal aortic aneurysm in a controlled trial

Antioxidants may retard atherogenesis and limit inflammatory processes involved in aneurysm formation. We evaluated effects of α-tocopherol and β-carotene supplementation on incidence of large abdominal aortic aneurysm (AAA) in a randomised, double-blind, placebo-controlled trial. Subjects (n=29 133) were 50–69-years-old male smokers, participants in the Finnish α-Tocopherol, β-Carotene Cancer Prevention (ATBC) Study. They were randomised to receive either 50 mg/day of α-tocopherol, or 20 mg/day of β-carotene, or both, or placebo in a 2×2 design. Incidence of AAA was evaluated from mortality and hospital registers. During 5.8 years of follow-up, 181 men were diagnosed with either ruptured AAA (n=77) or nonruptured large AAA treated with aneurysmectomy (n=104). Relative risk (RR) for AAA was 0.83 (95% confidence interval [CI] 0.62–1.11) among men receiving α-tocopherol compared with those who did not, and 0.93 (95% CI 0.69–1.24) among men receiving β-carotene compared with those who did not. A modest though nonsignificant decrease in risk for nonruptured AAA was observed among α-tocopherol supplemented men (RR 0.71, 95% CI 0.48–1.04) compared with men not receiving α-tocopherol. For β-carotene, RR for nonruptured AAA was 0.86 (95% CI 0.59–1.27) compared with men not receiving β-carotene. Neither antioxidant affected risk for ruptured AAA. In conclusion, long-term supplementation with α-tocopherol or β-carotene had no preventive effect on large AAA among male smokers.