CASE-CONTROL STUDY OF PASSIVE SMOKING AT HOME AND RISK OF ACUTE MYOCARDIAL-INFARCTION

Objectives. We sought to study the relation between passive smoking at home and the risk of acute myocardial infarction (AMI). Background. P revious epidemiologic studies have linked environmental tobacco smoke to an increased risk of coronary heart disease, but the evidence to su pport this view is not strong enough. To study this issue further, we analyzed the data from a case-control study conducted in Argentina bet ween 1991 and 1994.Methods. Case patients included 336 never-smokers w ith AMI. Control patients were 446 never-smokers admitted to the same network of hospitals with a wide spectrum of acute disorders unrelated to smoking or to known or suspected risk factors for AMI. Data on the smoking habits of the participants' close relatives (spouse and child ren) were collected by trained interviewers using a structured questio nnaire. Results. Compared with subjects whose relatives had never smok ed, the multivariate odds ratios for passive smokers, according to the smoking status of their relatives, were 1.68 (95% confidence interval [Ca 1.20 to 2.37) for one or more relatives who smoked; 1.59 (95% CI 0.85 to 2.96) for a spouse who smoked; 1.24 (95% CI 0.61 to 2.52) for a spouse who smoked 1 to 20 cigarettes/day; 4.03 (95% CI 0.99 to 16.32 ) for a spouse who smoked >20 cigarettes/day; and 1.80 (95% CI 1.20 to 2.68) for one or more children who smoked. There was a significant in teraction between passive smoking and hypercholesterolemia (greater th an or equal to 240 mg/dl), hypertension,; diabetes and family history of MI. Conclusions. In never-smokers, passive smoking at home appeared to be associated with the risk of AMI, and similar to 14% of cases in men and 18% of cases in women in this Argentinian cohort are attribut able to passive smoking. (C) 1998 by the American College of Cardiolog y.