Congenital heart defects and parental occupational exposure to chemicals.

Background: Congenital heart defects (CHDs) are the most common major malformations in newborns. In this study we examined the associations between the occurrence of CHDs in children and periconceptional occupational parental exposures to chemicals.

Methods: In an age-matched case-control study with standardized data collection at c. 15 months after birth, 424 mothers and 421 fathers of a child with CHD and 480 mothers and 477 fathers of a non-malformed child, filled out questionnaires on periconceptional general and job characteristics. A job exposure matrix, which links the information on job title and a description of work tasks to an expert judgement on exposure to chemicals in the workplace, was used.

Results: The overall prevalence of occupational exposure to chemicals was 5.0 in cases and 6.2% in controls for mothers [odds ratio (OR) adjusted = 0.92; 95% confidence interval (CI): 0.26-3.25], while 22.3 and 15.9% for fathers, respectively (OR adjusted = 1.23; 95% CI: 0.39-3.91). No association of maternal occupational exposure to chemicals with risk of CHDs was found. Paternal exposure to phthalates was associated with a higher incidence of CHDs in general (OR adjusted = 2.08; 95% CI: 1.27-3.40). Paternal exposure to phthalates was associated with perimembranous ventricular septal defect (OR adjusted = 2.84; 95% CI: 1.37-5.92), to polychlorinated compounds with atrioventricular septal defect (OR adjusted = 4.22; 95% CI: 1.23-14.42) and to alkylphenolic compounds with coarctation of the aorta (OR adjusted = 3.85; 95% CI: 1.17-12.67).

Conclusions: Periconceptional paternal (but not maternal) occupational exposure to certain chemicals is associated with an increased risk of CHDs in children. The results, however, must be interpreted cautiously as exposure probabilities are a crude measure of exposure.