| Antioxidants are presently receiving attention for their postulated role in protecting against lipid peroxidation and thereby inhibiting atherosclerosis and its clinical sequelae. To determine if low levels of serum antioxidants are associated with subsequent myocardial infarction, we used a nested case-control design. All study participants had donated 15 ml of blood in 1974 for a serum bank. Cases (n = 123) were persons from 35 through 65 years of age at the time of first diagnosis of myocardial infarction in the 1980's. Two controls, matched for sex and age, were selected for each case, one from hospital admissions and one from the community for a total of 123 persons in each control group. Sera were assayed for several antioxidants, including four carotenoids (beta-carotene, lycopene, lutein and zeaxanthin) and alpha-tocopherol.;Results of the study showed a trend of increasing risk for myocardial infarction with decreasing levels of beta-carotene (case: hospital control comparison, p value for trend = 0.02, case: community control comparison, p value for trend = 0.09). When persons having values of serum beta-carotene in the lowest quintile were compared with persons in the highest quintile, the risk of myocardial infarction increased about two-fold (case vs hospital control comparison: odds ratio = 2.47, 95% confidence interval (CI) = 1.15-5.33; in case vs community control comparison: odds ratio = 1.92, 95% CI = 0.82-4.48). When the association between beta-carotene and myocardial infarction was examined by smoking status, the risk for myocardial infarction associated with low levels of beta-carotene was limited to smokers. A weak protective association between high levels of alpha-tocopherol and myocardial infarction was suggested for persons with high levels of serum cholesterol. |
