Spina bifida and parental occupation: results from three malformation monitoring programs in Europe.

As the evidence for an association between spina bifida and parental agricultural occupations is inconclusive, we evaluated this association and the potential associations between spina bifida and other parental occupations. Three register-based case-referent studies were conducted in Sweden, Spain, and Hungary. From the registries of congenital malformations in each country, 482, 478, and 1119 cases with spina bifida were identified, respectively. Identified as referents were 964, 434, and 1489 children without abnormalities. Information on parental occupation was available in the registries from questionnaires or interviews conducted among the parents. Occupations with a potential for physical or chemical exposure were compared to non-exposed occupations. Increased odds ratios (ORs) were observed for women in agricultural occupations in Sweden (OR: 1.8, 95% CI: 0.8-4.2) and in Spain (OR: 2.2, 95% CI: 0.8-5.9), but not in Hungary (OR: 1.1, 95% CI: 0.7-1.7). Several other parental occupations were analysed, but the associations with spina bifida were inconsistent. Concluding, the results are not totally consistent but point to an increased risk of spina bifida among women in agricultural occupations.