Associations between maternal occupational history and autism spectrum disorder diagnosis in offspring in Denmark.

OBJECTIVES

We investigated associations between maternal occupations and a diagnosis of autism spectrum disorder (ASD) in offspring.

METHODS

We obtained data for 1702 ASD cases born between 1973 and 2012 from the Danish National Patient Registry and matched each case to up to 100 population based controls based on sex and birth year (n=110 234). Mothers' employment histories were obtained from the Danish Pension Fund Registry. Conditional logistic regression models were used to test associations between occupations held ever, 1 year before conception, during pregnancy and during infancy, adjusting for the mother's age and history of neuropsychiatric disorders, parity and residential location.

RESULTS

There were increased odds of having a child with ASD for mothers who were employed before conception up to infancy in ground transportation (adjusted OR (aOR) 1.24, 95% CI 1.08 to 1.42; q=0.036), public administration (aOR 1.20, 95% CI 1.07 to 1.35; q=0.018) and military/defence occupations (aOR 1.59, 95% CI 1.39 to 1.82; q<0.001). Associations for judicial occupations and military/defence service were also apparent 1 year before conception and during pregnancy. We observed sex differences, with significant associations in male children for employment in ground transportation and defence occupations.

CONCLUSIONS

Associations between certain maternal employment categories with high toxicant or psychosocial stress exposure suggest future studies should focus on examining specific toxicant exposures common in those occupations and neurodevelopment in offspring. This is of particular concern for associations seen for occupations held several years before conception.