The epidemiology of idiopathic dilated cardiomyopathy in women: the Washington DC Dilated Cardiomyopathy Study.

We examined possible risk factors for idiopathic dilated cardiomyopathy in women by comparing newly diagnosed cases (N = 61) ascertained from five Washington DC area hospitals with neighborhood controls (N = 122) identified using a random digit dialing technique. We matched the cases and controls on 5-year age intervals and telephone exchange and analyzed the data using conditional logistic regression methods. We found that idiopathic dilated cardiomyopathy was associated with history of asthma, diabetes mellitus, hypertension, and black race. The association with hypertension was particularly strong among women who were less than 50 years of age [crude relative odds (RO) = 21.0, 95% confidence interval (CI) = 4.6-96.9]. We found a strong inverse association with history of oral contraceptive use (crude RO = 0.3, 95% CI = 0.1-0.7; adjusted RO = 0.1, 95% CI = 0.1-0.5, controlling for other identified risk factors). Only 13.2% (7 of 53) of the cases had a reported history of contraceptive use, as compared with 35.5% (43 of 121) of the controls. The possible protective effect from oral contraceptive use was not explained by race, educational attainment, asthma, diabetes mellitus, or hypertension, and was more pronounced among women who were less than 50 years of age.