Vitamin E supplementation may transiently increase tuberculosis risk in males who smoke heavily and have high dietary vitamin C intake.
Vitamin E and beta-carotene affect the immune function and might influence the predisposition of man to infections. To examine whether vitamin E or beta-carotene supplementation affects tuberculosis risk, we analysed data of the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC)Study, a randomised controlled trial which examined the effects of vitamin E (50 mg/d) and beta-carotene (20 mg/d) on lung cancer. The trial was conducted in the general community in Finland in 1985-93; the intervention lasted for 6.1 years (median). The ATBC Study cohort consists of 29,023 males aged 50-69 years, smoking at baseline, with no tuberculosis diagnosis prior to randomisation. Vitamin E supplementation had no overall effect on the incidence of tuberculosis (risk ratio (RR) = 1.18; 95% CI 0.87, 1.59) nor had beta-carotene (RR = 1.07; 95% CI 0.80, 1.45). Nevertheless, dietary vitamin C intake significantly modified the vitamin E effect. Among participants who obtained 90 mg/d or more of vitamin Cin foods (n 13,502), vitamin E supplementation increased tuberculosis risk by 72 (95% CI 4, 185)%. This effect was restricted to participants who smoked heavily. Finally, in participants not supplemented with vitamin E, dietary vitamin C had a negative association with tuberculosis risk so that the adjusted risk was 60 (95% CI 16, 81)% lower in the highest intake quartile compared with the lowest. Our finding that vitamin E seemed to transiently increase the risk of tuberculosis in those who smoked heavily and had high dietary vitamin C intake should increase caution towards vitamin E supplementation for improving the immune system.
Hemilä
Harri
H
Department of Public Health, University of Helsinki, Mannerheimintie 172, POB 41, Helsinki FIN-00014, Finland. harri.hemila@helsinki.fi
Kaprio
Jaakko
J
D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage; D001205:Ascorbic Acid / Q000008:administration & dosage*; D004032:Diet; D019587:Dietary Supplements; D005500:Follow-Up Studies; D005638:Fruit; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods; D012907:Smoking / Q000009:adverse effects*; D014376:Tuberculosis / Q000209:etiology*; D014675:Vegetables; D014810:Vitamin E / Q000008:administration & dosage* / Q000627:therapeutic use; D014815:Vitamins / Q000008:administration & dosage* / Q000627:therapeutic use; D019207:beta Carotene / Q000008:administration & dosage
D000975:Antioxidants; D014815:Vitamins; D019207:beta Carotene; D014810:Vitamin E; D001205:Ascorbic Acid