Perinatal outcome among children of men exposed to lead and organic solvents in the printing industry.

The authors investigated the hypothesis that paternal occupational exposures at the time of conception may affect the risk of postconception events by linking records from Oslo, Norway, printers' unions and the Medical Birth Registry of Norway. The linkage yielded 6,251 infants born during the period 1967-1986. On the basis of job classification, fathers were categorized as to their exposure to lead and solvents. Odds ratios were estimated by simple and stratified analysis of tabular data and logistic regression analysis, with children whose fathers were not in lead- or solvent-exposed categories being used as the reference group. In addition, all Oslo births taking place during the same period served as an external reference for computation of standardized morbidity ratios. The adjusted odds ratio for early preterm birth (16-27 weeks) was 5.4 (95% confidence interval (CI) 1.7-17.4) for infants with paternal exposure to solvents and 8.6 (95% CI 2.7-27.3) for children whose fathers were in the lead plus solvents category. The adjusted odds ratio for all perinatal deaths was 2.4 (95% CI 1.2-4.9) for children with fathers in the lead-exposed group and 1.9 (95% CI 0.96-3.7) for children with fathers in the lead plus solvents group. An increased risk of cleft lip was demonstrated, with interaction between sex and paternal exposure to lead: The standardized morbidity ratio for boys in the two subgroups with lead exposure was 4.1 (95% CI 1.8-8.1). Paternal exposure had little impact on birth weight, intrauterine growth, or total number of birth defects. The main problems of the study were the potential for nondifferential misclassification of exposure and the fact that it was not possible to control for potentially confounding life-style factors.