Effect of alpha-tocopherol and beta-carotene supplementation on macrovascular complications and total mortality from diabetes: Results of the ATBC Study

Abstract

Aim. To determine whether alpha-tocopherol or beta-carotene supplementation affects diabetic macrovascular complications and total mortality.

Methods. This study was carried out as part of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a double-blind, randomized trial with a 2×2 factorial design. A total of 29,133 middle-aged male smokers received either vitamin E 50 mg/day or beta-carotene 20 mg/day, or both, or placebo for a median of 6.1 years. At base-line, 1700 men had type 2 diabetes. Of these men, 662 were diagnosed with first-ever macrovascular complication, and 1142 died during the 19-year follow-up.

Results. Neither supplementation affected the risk of macrovascular complication or total mortality during the intervention period. For the alpha-tocopherol-supplemented versus no alpha-tocopherol-supplemented, and beta-carotene-supplemented versus no beta-carotene-supplemented we found relative risk (RR) 0.84 (95% confidence interval (CI) 0.65–1.10) and RR 1.15 (95% CI 0.89–1.50) for macrovascular complication, respectively, and RR 1.00 (95% CI 0.80–1.25) and RR 1.06 (95% CI 0.85–1.33) for total mortality, respectively. No essential changes were found in these effects when the follow-up was extended up to 19 years.

Conclusion. Alpha-tocopherol or beta-carotene supplementation has no protective effect on macrovascular outcomes or total mortality of diabetic male smokers.

Key words::

• Antioxidants
• cohort studies
• complications
• diabetes
• epidemiology
• mortality

Acknowledgements

This ATBC Study was supported by US Public Health Service contracts N01-CN-45165, N01- RC-45035, and N01-RC-37004 from the National Cancer Institute, National Institutes of Health, and the Department of Health and Human Services.

Declaration of interest: Nothing to declare.