Send to

Choose Destination
Cancer Causes Control. 2000 Aug;11(7):617-26.

Effects of beta-carotene supplementation on cancer incidence by baseline characteristics in the Physicians' Health Study (United States).

Author information

Department of Medicine, Brigham and Women's Hospital, Boston, MA 02215, USA.



The Physicians' Health Study (PHS) was a randomized trial of beta-carotene (50 mg, alternate days) and aspirin in primary prevention of cancer and cardiovascular disease among 22,071 US male physicians. This report updates results for beta-carotene and examines effect modification by baseline characteristics.


Beta-carotene's effect on cancer over nearly 13 years was examined overall and within subgroups defined by baseline characteristics using proportional-hazards models.


2667 incident cancers were confirmed, with 1117 prostate, 267 colon, and 178 lung cancers. There were no significant differences with supplementation in total (relative risk (RR) = 1.0, 95% confidence interval (CI) = 0.9-1.0); prostate (RR = 1.0, 95% CI = 0.9-1.1); colon (RR = 0.9, 95% CI = 0.7-1.2); or lung (RR = 0.9, 95% CI = 0.7-1.2) cancer, and no differences over time. In subgroup analyses, total cancer was modestly reduced with supplementation among those aged 70+ years (RR = 0.8, 95% CI = 0.7-1.0), daily drinkers of alcohol (RR = 0.9, 95% CI = 0.8-1.0), and those in the highest BMI quartile (RR = 0.9, 95% CI = 0.7-1.0). Prostate cancer was reduced with supplementation among those in the highest BMI quartile (RR = 0.8, 95% CI = 0.6-1.0), and colon cancer was reduced among daily drinkers of alcohol (RR = 0.5, 95% CI = 0.3-0.8).


The PHS found no overall effect of beta-carotene on total cancer, or the three most common site-specific cancers. The possibility of risk reduction within specific subgroups remains.

[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center