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.