Effects of alpha-tocopherol and beta-carotene supplementation on gastric cancer incidence in male smokers (ATBC Study, Finland)

Abstract

Objectives: This study investigated the effects of alpha-tocopherol and beta-carotene supplementation on the incidence of gastric cancer.

Methods: A total of 29,133 male smokers, aged 50-69 years, participated in a placebo-controlled prevention trial, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study in southwestern Finland between 1985 and 1993. The men were randomly assigned to receive alpha-tocopherol (50 mg/day) or beta-carotene (20 mg/day) supplementation in a 2 x 2 factorial design. We identified 126 gastric cancer cases during the median follow-up of six years. Of these, 122 were adenocarcinomas: 75 of intestinal type, 30 of diffuse type, and 17 of mixed type.

Results: There was no significant effect for either supplementation on the overall incidence of gastric cancer: relative risk (RR) 1.21, 95% confidence interval (CI) 0.85-1.74 for alpha-tocopherol, and RR 1.26, 95% Cl 0.88-1.80 for beta-carotene. Subgroup analyses by histologic type suggested an increased risk for beta-carotene on intestinal type cancers, RR 1.59, 95% CI 0.99-2.56. There were no differences across anatomic locations (cardia/noncardia) in the effects of alpha-tocopherol or beta-carotene supplementation.

Conclusions: Our study found no overall preventive effect of long-term supplementation with alpha-tocopherol or beta-carotene on gastric cancer in middle-aged male smokers.