Incidence of myocardial infarction in women. A cohort study of risk factors and modifiers of effect

Study objective-To assess whether the increased incidence of myocardial inf arction and death associated with smoking, hypertension, hyperlipidaemia an d diabetes varies significantly between groups defined in terms of occupati on, education and marital status. Setting-Malmo, Sweden. Participants-9351 women, aged 28-55, with a mean follow up of 10.7 years. Main results-Smoking, hypertension (greater than or equal to 160/95 mm Hg o r treatment), hyper- lipidaemia (cholesterol greater than or equal to 6.5 m mol/l or triglycerides greater than or equal to 2.3 mmol/l), diabetes, low The occupation and education levels were significantly more common among wo men who experienced a fatal or nonfatal myocardial infarction during the fo llow up (n=104) than in other women (n=9247). Exposure to smoking, hyperten sion and hyperlipidaemia showed substantial differences between groups defi ned in terms of education, occupation and marital status. The association b etween low occupation and myocardial infarction remained statistically sign ificant after adjustments for several potential confounders (RR=2.6, 95%CI 1.1, 6.0). Single women had similarly higher adjusted mortality rates than married women (RR=1.4, 95%CI 1.1, 1.8). When other major risk factors were taken into account, the relative risk for mortality and myocardial infarcti on associated with smoking was 2.6 (95%CI 2.0, 3.4) and 7.8 (95%CI 4.4 13.9 ), respectively Conclusion-In this urban female population, short education and low occupat ion level were both associated with an increased prevalence of smoking, hyp ertension, hyperlipidaemia and diabetes. Low occupation level increases the rate of cardiac events caused by exposure to these four risk factors.