Parental employment at time of conception and risk of cancer in offspring.

Studies on the possible association between exposures of parents at the time off conception and cancer in their offspring have provided no clear answer. In this large, population-based, record-linkage study, 1747 childhood cancer cases were identified in the Danish Cancer Registry and matched with 8630 population controls. Specific information on the employment held by each parent at the time of conception and during early pregnancy was obtained through record linkages. The most recent job titles of the parents were also supplied. Significantly increased risks for renal cancer (mainly Wilms' tumour) and for osteogenic and soft tissue sarcomas were observed in children in association with mothers' employment in medical and dental care, based on 15 observations and odds ratios (OR) of 2.5-4.0. The risk for cancers at all sites was significantly elevated in children of female nurses (OR = 1.4; n = 75) and of male and female physicians, dentists, dental assistants, veterinarians and pharmacists combined (OR = 1.4; n = 53). Handling of drugs, exposure to anaesthetics and infections during pregnancy are suggested to be potential risk factors. Significantly increased risks were also observed for children of fathers employed in the manufacture of iron and metal structures (OR = 2.2; n = 16), in machine repair workshops (OR = 2.8; n = 6), as machinists (OR = 1.6; n = 47) and as smiths (OR = 1.5; n = 28). The suggestion in earlier studies that exposures to hydrocarbons and lead are risk factors for childhood cancer could not be supported by our analysis. Overall, few associations were observed; it was therefore concluded that parental occupation is not likely to be a major risk factor for childhood cancer.