Vitamin A, retinol, and carotenoids and the risk of gastric cancer: a prospective cohort study.
Am J Clin Nutr. 2007 Feb;85(2):497-503. PMID: 17284749
BACKGROUND: Vitamin A may influence gastric carcinogenesis through its essential role in controlling cell proliferation and differentiation. However, epidemiologic studies of vitamin A, retinol (preformed vitamin A), and provitamin A carotenoids in relation to the risk of gastric cancer have documented inconsistent results. OBJECTIVE: The objective of the study was to examine the associations between intakes of vitamin A, retinol, and specific carotenoids and the risk of gastric cancer in a prospective population-based cohort study of Swedish adults. DESIGN: The study cohort consisted of 82 002 Swedish adults aged 45-83 y who had completed a food-frequency questionnaire in 1997. The participants were followed through June 2005. RESULTS: During a mean 7.2-y follow-up, 139 incident cases of gastric cancer were diagnosed. High intakes of vitamin A and retinol from foods only (dietary intake) and from foods and supplements combined (total intake) and of dietary alpha-carotene and beta-carotene were associated with a lower risk of gastric cancer. The multivariate relative risks for the highest versus lowest quartiles of intake were 0.53 (95% CI: 0.32, 0.89; P for trend = 0.02) for total vitamin A, 0.56 (95% CI: 0.33, 0.95; P for trend = 0.05) for total retinol, 0.50 (95% CI: 0.30, 0.83; P for trend = 0.03) for alpha-carotene, and 0.55 (95% CI: 0.32, 0.94; P for trend = 0.07) for beta-carotene. No significant associations were found for beta-cryptoxanthin, lutein and zeaxanthin, or lycopene intake. CONCLUSION: High intakes of vitamin A, retinol, and provitamin A carotenoids may reduce the risk of gastric cancer.