Incidence of cancer and mortality following alpha-tocopherol and beta-carotene supplementation: a postintervention follow-up.
BACKGROUND
In the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, alpha-tocopherol supplementation decreased prostate cancer incidence, whereas beta-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 beta-carotene on cancer incidence and total and cause-specific mortality.


METHODS
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 25 563 men. In the ATBC Study, 29 133 male smokers aged 50 to 69 years received alpha-tocopherol (50 mg), beta-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.


METHODS
Site-specific cancer incidence and total and cause-specific mortality and calendar time-specific risk for lung cancer incidence and total mortality.


RESULTS
Overall posttrial relative risk (RR) for lung cancer incidence (n = 1037) was 1.06 (95% confidence interval [CI], 0.94-1.20) among recipients of beta-carotene compared with nonrecipients. For prostate cancer incidence (n = 672), the RR was 0.88 (95% CI, 0.76-1.03) for participants receiving alpha-tocopherol compared with nonrecipients. 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% CI, 0.96-1.05) for alpha-tocopherol recipients vs nonrecipients and 1.07 (95% CI, 1.02-1.12) for beta-carotene recipients vs nonrecipients. Regarding duration of intervention effects and potential late effects, the excess risk for beta-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 alpha-tocopherol and beta-carotene disappeared during postintervention follow-up. The preventive effects of alpha-tocopherol on prostate cancer require confirmation in other trials. Smokers should avoid beta-carotene supplementation.
Virtamo
Jarmo
J
National Public Health Institute, Helsinki, Finland.
Pietinen
Pirjo
P
Huttunen
Jussi K
JK
Korhonen
Pasi
P
Malila
Nea
N
Virtanen
Mikko J
MJ
Albanes
Demetrius
D
Taylor
Phil R
PR
Albert
Paul
P
D000368:Aged; D000975:Antioxidants / Q000627:therapeutic use*; D002423:Cause of Death; D019587:Dietary Supplements; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D011471:Prostatic Neoplasms / Q000453:epidemiology; D012306:Risk; D012907:Smoking / Q000009:adverse effects*; D024502:alpha-Tocopherol / Q000627:therapeutic use*; D019207:beta Carotene / Q000627:therapeutic use*
D000975:Antioxidants; D019207:beta Carotene; D024502:alpha-Tocopherol