Are maternal occupation and residential proximity to industrial sources of pollution related?

We examined the relation between maternal occupation and residential proximity to industrial sources of pollution in two case-control study populations of birth defects.

Occupational and residential information were obtained from Texas live birth records and maternal interviews of Texas participants in the National Birth Defects Prevention Study. Residential proximity to industrial sources of air pollution was determined through geographic information systems.

With adjustment for maternal race/ethnicity and education, women in production occupations were twice as likely (95% confidence interval 1.3 to 3.0) to reside near these facilities than women in management/professional occupations and more likely to reside near such facilities than other occupational groups.

Occupation and residence appear related; therefore, both sources of potential exposures may need to be considered to understand the relative contribution of either source to risk of adverse pregnancy outcomes.