FREQUENCY OF FAMILY HISTORY OF ACUTE MYOCARDIAL-INFARCTION IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

The relation between family history of acute myocardial infarction (AM I) and the risk of AMI was analyzed using data of a case-control study conducted in Argentina between 1992 and 1994. Case patients were 1,06 0 subjects with AMI admitted to 35 coronary care units, and controls w ere 1,071 subjects admitted to the same network of hospitals where cas es had been identified, for a wide spectrum of acute conditions unrela ted to known or likely risk factors for AMI: 31% of cases versus 15% o f controls reported greater than or equal to 1 first-degree relative w ith history of AMI. Compared with subjects without family history of A MI, the odds ratio (OR) of AMI, after allowance for age, sex, choleste rolemia, smoking, diabetes, hypertension, body mass index, education, social class, and physical exercise, was 2.18 (95% confidence interval [CI] 1.74 to 2.74) for those with family history of AMI. The OR was 2 .04 (95% CI 1.60 to 2.60) for subjects with 1 relative, and 3.18 (95% CI 1.86 to 5.44) for those reporting greater than or equal to 2 relati ves with AMI, in women the OR for any family history of AMI was 2.83, and in men 2.01. The association was of similar magnitude if the mothe r (OR 1.98), the father (OR 2.13), or a sibling (OR 2.48) had had an A MI. The association with family history was stronger at a younger age because the OR for subjects reporting greater than or equal to 2 more relatives with a history of AMI was 4.42 for subjects aged <55 years, and 3.00 for those aged greater than or equal to 55 years. The associa tion between AMI and family history of AMI was consistent across separ ate strata of education, social class, smoking, and serum cholesterol, bur was less strong in subjects with history of diabetes and hyperten sion. When the interaction of known risk factors with family history o f AMI was analyzed, hypercholesterolemia, hypertension, and smoking ha d approximately multiplicative effects on the relative risk. The OR wa s 4.50 for subjects with family history and cholesterol greater than o r equal to 240 ml/dl, 4.52 for those with hypertension, and 5.77 for c urrent smokers with family history of AMI. Thus, this study confirms t hat a family history of AMI is a strong and independent risk factor fo r AMI. In this population from Argentina, family history accounted for 14% of all cases of AMI in men and 26% in women. (C) 1997 by Excerpta Medica, Inc.