Gender heterogeneity in the association between lifestyles and non-fatal acute myocardial infarction.

OBJECTIVE To evaluate the modification effect of sex in the association between lifestyles and acute myocardial infarction (AMI). DESIGN Population-based case-control study. Trained interviewers collected information using a standard structured questionnaire. Associations were estimated using unconditional logistic regression. The effect modification by sex was evaluated in the regression models, testing interaction terms between lifestyles and sex. SETTING Porto, Portugal. SUBJECTS Portuguese Caucasian adults, aged > or =18 years. Cases were patients consecutively admitted with an incident AMI during 1999-2003 (n 918) and controls were a representative sample of non-institutionalized inhabitants of Porto with no evidence of previous clinical or silent infarction (n 2316). RESULTS Cigarette smoking was positively associated with AMI in both men and women (smokers >15 cigarettes/d v. never smokers: OR = 9.11, 95% CI 4.83, 17.20 for women; OR = 3.92, 95% CI 2.75, 5.58 for men; interaction term P value = 0.001). A significant protective effect of moderate alcohol intake on AMI occurrence was found in women (0.1-15.0 g/d v. non-drinkers: OR = 0.48, 95% CI 0.31, 0.74), but not in men. Fruit and vegetable intake, vitamin and mineral supplement use and leisure-time physical activity practice were found to decrease AMI risk, with similar effects between sexes. CONCLUSIONS A strong positive association between smoking and AMI was found in women. Also, a protective effect of moderate alcohol intake was only found among females. Fruit and vegetable intake, vitamin and mineral supplement use and leisure-time physical activity practice were found to decrease AMI risk in both sexes.