Idiopathic dilated cardiomyopathy and atopic disease: epidemiologic evidence for an association with asthma.

Because of recent evidence from in vitro studies suggesting that immediate hypersensitivity or other autoimmune mechanisms may play a role in the initiation or progression of idiopathic dilated cardiomyopathy (DCM), an epidemiologic study was carried out to examine possible associations with atopic diseases and other immunologic disorders. Newly diagnosed cases were ascertained from four Baltimore hospitals and were interviewed along with neighborhood controls identified using a random digit dialing technique. The cases and controls (N = 190) were matched on sex and 5-year age intervals and were compared in the analysis using matched and unmatched estimates of the relative odds and conditional logistic regression methods. A statistically significant, independent association was observed between idiopathic DCM and a history of asthma (p less than 0.05). The association was most pronounced among individuals who were less than 55 years of age (relative odds = 20.3, p less than 0.05), with 31.1% (14 of 45) of the patients who were under the age of 55 having a reported history of asthma. These findings support the theory that hypersensitivity mechanisms may be important in the development of idiopathic DCM. A treatment effect associated with asthma is an alternative possibility.