The Beta Carotene and Retinol Efficacy Trial - CARET


Carotenoids and retinoids for prevention of CAD and lung cancer.


Carotenoids and retinoids may prevent cardiovascular disease and lung cancer.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 18,314
Mean Follow Up: 4 years
Mean Patient Age: 57
Female: 34

Patient Populations:

Exposure to asbestos on the job 15 years before randomization and either have had a chest x-ray film positive for asbestos-related lung disease or have worked in specified high-risk trades for 5 years. The asbestos pilot study had no requirements regarding smoking.

Subsequently, subjects were required to be current smokers or to have smoked within the previous 15 years.


Not given

Primary Endpoints:

Cancers and death

Drug/Procedures Used:

Beta carotene beadlets combined with retinyl palmitate in a single capsule (30mg of beta carotene per day and 25,000 IU of retinol).

Principal Findings:

A total of 388 new cases of lung cancer were diagnosed during the 73,135 person-years of follow-up (mean length of follow-up, 4.0 years).

The active-treatment group had a relative risk of lung cancer of 1.28 (95 percent confidence interval, 1.04 to 1.57; P=0.02), as compared with the placebo group. There were no statistically significant differences in the risks of other types of cancer.

In the active-treatment group, the relative risk of death from any cause was 1.17 (95 percent confidence interval, 1.03 to 1.33); of death from lung cancer, 1.46 (95 percent confidence interval, 1.07 to 2.00); and of death from cardiovascular disease, 1.26 (95 percent confidence interval, 0.99 to 1.61).

On the basis of these findings, the randomized trial was stopped 21 months earlier than planned; follow-up will continue for another 5 years.


After an average of four years of supplementation, the combination of beta carotene and vitamin A had no benefit and may have had an adverse effect on the incidence of lung cancer and on the risk of death from lung cancer, cardiovascular disease, and any cause in smokers and workers exposed to asbestos.


1. N Engl J Med 1996;334:1150-55. Design and baseline results.

Clinical Topics: Prevention, Smoking

Keywords: Carotenoids, beta Carotene, Retinoids, Vitamin A, Cardiovascular Diseases, Coronary Disease, Tobacco Use Disorder, X-Ray Film, Lung Neoplasms, Smoking

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