Résumé :
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[BDSP. Notice produite par INIST-CNRS lINgeR0x. Diffusion soumise à autorisation]. Context : In the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, alpha-tocopherol supplementation decreased prostate cancer incidence, whereas bêta-carotene increased the risk of lung cancer and total mortality. Postintervention follow-up provides information regarding duration of the intervention effects and may reveal potential late effects of these antioxidants. Objective : To analyze postintervention effects of alpha-tocopherol and bêta-carotene on cancer incidence and total and cause-specific mortality. Design, Setting, and Participants : Postintervention follow-up assessment of cancer incidence and cause-specific mortality (6 years [May 1,1993-April 30,1999]) and total mortality (8 years [May 1,1993-April 30,2001]) of 25563 men. In the ATBC Study, 29133 male smokers aged 50 to 69 years received alpha-tocopherol (50 mg), (3-carotene (20 mg), both agents, or placebo daily for 5 to 8 years. End point information was obtained from the Finnish Cancer Registry and the Register of Causes of Death. Cancer cases were confirmed through medical record review. Main Outcome Measures : Site-specific cancer incidence and total and cause-specific mortality and calendar time-specific risk for lung cancer incidence and total mortality. Results : Overall post trial relative risk (RR) for lung cancer incidence (n=1037) was 1.06 (95% confidence interval [Cl], 0.94-1.20) among recipients of bêta-carotene compared with non recipients. For prostate cancer incidence (n=672), the RR was 0.88 (95% Cl, 0.76-1.03) for participants receiving alpha-tocopherol compared with non recipients. No late preventive effects on other cancers were observed for either supplement. There were 7261 individuals who died by April 30,2001, during the posttrial follow-up period ; the RR was 1.01 (95% Cl, 0.96-1.05) for alpha-tocopherol recipients vs non recipients and 1.07 (95% Cl, 1.02-1.12) for (3-carotene recipients vs non recipients. Regarding duration of intervention effects and potential late effects, the excess risk for (3-carotene recipients was no longer evident 4 to 6 years after ending the intervention and was primarily due to cardiovascular diseases. Conclusions : The beneficial and adverse effects of supplemental a-tocopherol and (3-carotene disappeared during postintervention follow-up. The preventive effects of a-tocopherol on prostate cancer require confirmation in other trials. Smokers should avoid (3-carotene supplementation.
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