FROM:
J Cardiovasc Risk 1996 (Aug); 3(4): 368–371
Gaziano JM
Department of Medicine,
Brigham and Women's Hospital,
Boston, MA
02215–1204, USA
The hypothesis that antioxidant vitamins might reduce
cardiovascular disease risk is based on a large body of basic and
human epidemiologic research. Basic research provides a plausible
mechanism by which antioxidants might reduce the risk of
atherosclerosis. A large number of descriptive, case–control and
cohort studies provide data suggesting that consumption of
antioxidant vitamins is associated with reduced risks of
cardiovascular disease. These data raise the question of a role
of antioxidants, such as vitamins C and E, and beta–carotene, in
the primary prevention of cardiovascular disease, but do not
provide a definitive answer. Randomized trial data will be
essential in establishing whether or not there is a causal effect
of antioxidants in reducing the risk of cardiovascular disease.
For many hypotheses randomized trials are neither necessary nor
desirable; however, when searching for small to moderate effects,
large–scale randomized trials of adequate dose and duration, in
which investigators allocate subjects at random to either active
treatment or placebo will provide valuable information about
whether there is a causal relationship, and provide reliable
estimates of effect size. Results from several large–scale
randomized trials of antioxidants are summarized in this paper.
At present, there is not sufficient data available to define
clearly the role of antioxidants in primary or secondary
prevention of cardiovascular disease. Additional trial data
should be forthcoming in the near future which will aid in
individual clinical decision–making and in the establishment of
guidelines for the general public.