Environmental factors and risk of idiopathic dilated cardiomyopathy: A multi-hospital case-control study in Japan

Abstract

Background: Detailed epidemiological investigations on the relationship of environmental factors, especially occupational and microbiological factors, to the development of idiopathic dilated cardiomyopathy (IDC) are scarce. Methods and Results: A multi-hospital case-control study was conducted in 38 hospitals throughout Japan in order to survey IDC cases and age, sex-matched outpatient controls at each hospital. Crude and adjusted odds ratios (ORs) by various environmental factors were calculated in 135 pairs of cases and controls. Univariate analyses revealed significantly increased ORs for lower education, passive smoking in the workplace, cold and/or hot workplace, symptoms of fatigue and history of bacterial infection; in contrast, decreased ORs were associated with a history of rubella and gastroduodenal diseases. Based on multivariate adjusted analyses, lower education (OR 1.96, 95% confidence interval (CI) 1.13-3.40), cold or hot workplace (OR 1.84, 95% CI 1.08-3.12) and history of measles (OR 1.78, 95% CI 1.01-3.08) exhibited a significant positive relationship with IDC risk. History of rubella (OR 0.17, 95% CI 0.06-0.52) and gastroduodenal diseases (OR 0.14, 95% CI 0.07-0.29) were inversely related to the risk. Conclusions: Some occupational and microbiological factors appear to relate independently to the development of IDC and further investigation is required to establish their respective mechanisms.