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Effect of vitamin E and beta carotene on the incidence of angina pectoris. A randomized, double-blind, controlled
J M Rapola1, J Virtamo, J K Haukka
1National Public Health Institute, Helsinki, Finland.
Objective:
To examine the effect of supplementation with vitamin E (alpha tocopherol), beta carotene, or both on the incidence of angina pectoris in men without known previous coronary heart disease.
Design:
Randomized, double-blind, placebo-controlled trial.
Setting And Participants:
Participants in the Alpha Tocopherol, Beta Carotene Cancer Prevention Study (N=29133) were male smokers aged 50 through 69 years who were living in southern and western Finland. Of these men, 22269 were considered free of coronary heart disease at baseline and were followed up for the incidence of angina pectoris.
Intervention:
Participants were randomized to receive 50 mg/d of alpha tocopherol, 20 mg/d of beta carotene, both, or placebo in a 2x2 design.
Outcome Measures:
An incident case was defined as the first occurrence of typical angina pectoris identified in administering the annually repeated World Health Organization (Rose) Chest Pain Questionnaire.
Results:
During a median follow-up time of 4.7 years (96427 person-years), 1983 new cases of angina pectoris were detected. Comparing alpha tocopherol-supplemented subjects with non-alpha tocopherol-supplemented subjects showed a relative risk (RR) of angina pectoris incidence of 0.91 (95% confidence interval[CI], 0.83 to 0.99; P=.04). The RR for incidence of angina pectoris for the beta carotene- supplemented subjects compared with those not receiving beta carotene was 1.06 (95% CI, 0.97 to 1.16; P=.19). Compared with those receiving placebo, the RRs for incidence of angina pectoris were 0.97 (95% CI, 0.85 to 1.10) and 0.96 (95% CI, 0.85 to 1.09) in the alpha tocopherol and alpha tocopherol plus beta carotene groups, respectively, and 1.13 (95% CI, 1.00 to 1.27) in the beta carotene group (P=.06). Baseline dietary intakes and serum levels of alpha tocopherol and beta carotene did not predict incidence of angina pectoris.
Conclusions:
Supplementation with alpha tocopherol was associated with only a minor decrease in the incidence of angina pectoris. Beta carotene had no preventive effect and was associated with a slight increase of angina.