Family history as a risk factor for early onset myocardial infarction in young women

Background: The relation between a family history of heart attack and the o ccurrence of early myocardial infarction (MI) has not been studied extensiv ely in women. In addition, whether recognized and newly-identified coronary heart disease (CHD) risk factors account for the familial aggregation of t hese events remains unknown. We therefore examined these questions in a pop ulation-based case-control study among female 18- to 44-year-old residents of western Washington State. Methods and Results: The patients consisted of 107 women with first acute MI, and the control subjects comprised 526 wome n similar in age identified from the community and without a history of rec ognized clinical coronary heart disease or stroke. Trained interviewers use d a structured questionnaire to elicit a detailed history of heart attack i n first-degree relatives. Information about other known MI risk factors was collected and biochemical measurements performed, and common polymorphisms in various candidate genes were determined. The rate of MI among first-deg ree relatives of MI cases was twice as high as among first-degree relatives of controls (relative risk, 1.96; 95% confidence interval (CI), 1.46-2.48) ; this association was present for each familial relationship. Sibling hist ory of MI but not parental history was associated with MI, after controllin g for established CHD risk factors. In a subsample of subjects with blood m easurements, further adjustment for lipids, lipoproteins and specific genet ic risk factors slightly reduced the association with sibling MI history (f rom odds ratio (OR), 5.17; 95% CI, 1.93-13.85 to OR. 3.97; 95% CI, 0.92-17. 17). Conclusion: Family history of MI is positively associated with the ris k of early MI in women. While the association with parental history of MI i s mediated through the clustering of other common risk factors, the associa tion of sibling history of MI with early-onset MI in young women is only pa rtially explained by the clustering of established and newly-identified ris k factors. (C) 2001 Elsevier Science Ireland Ltd, All rights reserved.