Antioxidants do not protect male smokers from heart disease
NEW YORK (Reuters Health) - The results of a 6-year post-trial follow-up of the Finnish alpha-tocopherol, beta-carotene cancer prevention (ATBC) study provide no evidence that either of these two antioxidants protect the heart of men who smoke.
They may actually be harmful, cardiologists report in the July issue of the European Heart Journal.
In the ABTC Study, 29,133 male smokers between 50 and 69 years old were randomized to 50 mg alpha-tocopherol, 20 mg beta-carotene, both antioxidants, or placebo daily for 5 to 8 years.
At the start of the post-trial follow up period, 23,144 men remained at risk for a first-ever major coronary event, whereas 1255 had had an MI and were at risk for a second event.
During the 6-year post-trial period, a total of 2059 first-ever major coronary events were recorded, 993 of which were non-fatal MIs and 1066 fatal CHD events.
According to the team, alpha-tocopherol supplementation had no significant impact during the post-trial period on first-ever major coronary events, similar to observations made during the trial period.
Beta-carotene supplementation, on the other hand, increased the post-trial risk for major coronary events and non-fatal MI by 14% and 16%, respectively.
The post-trial risk for fatal CHD events increased by 11% in beta-carotene users compared with nonusers, but this did not reach statistical significance.
"These findings of beta-carotene were unexpected," the team admits, "since no increased risk was observed during the trial period when the corresponding relative risks were 1% for [major coronary events], 0% for non-fatal MI, and 2% for fatal CHD." This may be a chance finding, they suggest.
These post-trial ATBC study data on the late effects of alpha-tocopherol and beta-carotene argue against their use in male smokers for the prevention of CHD.