Noncontraceptive estrogens and myocardial infarction in young women.
The effect of noncontraceptive estrogens on the risk of myocardial infarction (MI) in women aged 30 to 49 years was investigated in 477 women with first infarctions and in 1,832 hospital control subjects. There was little evidence of an effect: overall, the estimated relative risk of acute MI for women who had used noncontraceptive estrogens in the preceding month, after allowance for potential confounding factors, was 1.0 (95% confidence intervals, 0.6 to 1.7); the corresponding estimate for women who had discontinued use more than one month previously was 1.2 (0.8 to 1.8). There was also no apparent association in various subgroups, including women who smoked heavily and those who had no identified predisposition.