Influence of selected lifestyle factors on risk of acute myocardial infarction in subjects with familial predisposition for the disease

Background. The joint effect of family history of acute myocardial infarction (AMI) and selected adult life risk factors on the risk of the disease is not clear. Methods. We used the combined data set from three Italian case-control studies including 1,737 cases of incident, nonfatal AMI and 2,317 hospital controls, aged less than 75 years. An adult lifestyle risk score (ALRS) was computed, including tobacco, body mass index, physical activity, and consumption of coffee, alcohol, fish, and vegetables. Results. Compared to the reference category (subjects with no family history of AMI and low ALRS), the risk of AMI was 4.97 (95% confidence intervals, CI: 4.00-6.18) in subjects without family history and high ALRS, 2.19 (95% CI: 1.65-2.90) in subjects with family history and low ALRS, and 11.90 (95% CI: 8.94-15.84) in subjects with family history and high ALRS. Conclusions. The risk of AMI in subjects with a familial predisposition to ischaemic heart disease might be substantially reduced by intervention on selected lifestyle risk factors for AMI. In absolute terms, any such intervention would be more effective than a comparable one on subjects without a familial predisposition.