The association between use of oral contraceptives (OC) and death from myocardial infarction (MI) in young women was investigated in a collaborative case-control study conducted in the five largest metropolitan areas in the US. Potential cases were identified from computer tapes of the National Center for Health Statistics. Controls were selected from among women who died from, or were hospitalized for, acute conditions other than heart disease or from accidents, and were matched to cases on age, geographic area, and year of death. Information on cause of death, personal characteristics, OC use, and the presence of conditions predisposing to MI was obtained from interviews with relatives and abstracts of hospital, clinic and physician records. Odds ratios as approximations to relative risks for fatal MI in relation to OC use, and the associated 95% confidence limits, were calculated overall and for subgroups determined by demographic and health history characteristics. Odds ratios in the total study population were not significantly different from one. However, odds ratios significantly different from one were found when attention was restricted to white subjects without contraindications to OC use, andincluding only those cases whose deaths were attributed to MI with the greatest degree of certainty. Smoking was found to be a significant risk factor for fatal MI.
PIP: A collaborative case-control study was conducted in the 5 largest metropolitan areas in the United States in order to investigate the association between oral contraceptive (OC) use and death from myocardial infarction (MI) in young women. Potential cases were identified from computer tapes of the National Center for Health Statistics. The controls were selected from among women who died from, or were hospitalized for, acute conditions other than heart disease or from accidents; they were matched to cases on age, geographic area, and year of death. The population of study cases was defined to be all women, age 15-44, who died of an acute MI during the January 1974-June 1975 period. 163 cases were classified as either MI or sudden death (SD). Information regarding cause of death, personal characteristics, OC use, and the presence of conditions predisposing to MI was obtained from interviews with relatives and abstracts of hospital, clinic and physician records. Odds ratios as approximations to relative risks for fatal MI in relation to OC use, and the associated 95% confidence limits, were calculated overall and for subgroups determined by demographic and health history characteristics. Odds ratios in the total study population were not significantly different from 1, but odds ratios significantly different from 1 were found when attention was restricted to white subjects without contraindications to OC use, and including only those cases whose deaths were attributed to MI with the greatest risk of certainty. A signficant risk factor for fatal MI was smoking. The data suggest that use of OCs may increase the risk of death from MI.