Infants with single ventricle: a population-based epidemiological study.

BACKGROUND Single ventricle, a rare congenital cardiac defect, often occurs as part of a complex group of cardiovascular abnormalities. Little is known of its epidemiologic associations. METHODS Using data from the Baltimore-Washington Infant Study [BWIS], (1981-89), a population based case-control study of cardiovascular malformations, infants with single ventricle were evaluated with respect to infant and family characteristics and maternal and paternal exposures. The cases were analyzed according to presence/absence of abnormal cardio-visceral situs. Controls were 3,572 infants without heart defects randomly selected from the regional cohort of live births. Odds ratios and 95% confidence intervals were used as measures of association. RESULTS Single ventricle occurred in 1.25% of infants with congenital cardiovascular defects in the BWIS. Fifty-five infants had single ventricle. In 48 families (87.3%) the parents were interviewed. Thirty-three infants had normal situs and 15 had abnormal situs. Paternal alcohol consumption (OR = 2.0, 95% CI 1.1-3.9) and paternal cigarette smoking (OR = 2.4, 95% CI 1.1-5.1) were associated with all cases of single ventricle. These associations were even stronger in the subset of infants with abnormal situs. Maternal history of a previous induced abortion was also associated with infants born with abnormal situs (OR = 3.2, 95% CI 1.1-11.5). Paternal marijuana use was associated with cases of single ventricle in normal situs (OR = 2.2, 95% CI 1.0-5.2). CONCLUSIONS Potential risk factors included paternal smoking and alcohol consumption, highlighting the need for future studies to consider environmental factors in the pathogenesis of this cardiac defect.