Maternal occupational physical activity and risk for orofacial clefts.

OBJECTIVES: To perform a case-control study of maternal occupational physical activity and risk for orofacial clefts in Texas during 1999-2009.

METHODS: We used logistic regression to assess 14 measures of physical activity estimated from a job exposure matrix, using the maternal occupation reported on the birth certificate, among 887 children with cleft lip with or without cleft palate (CLP), 436 children with cleft palate only (CP), and 1932 controls.

RESULTS: After adjusting for several potential confounders, seven measures of physical activity (as a categorical and/or continuous variable) were significantly associated with CLP, CP, or both. Positive associations were seen for keeping balance, kneeling, standing, and walking/running (odds ratio 95% confidence interval range 1.0-1.9 for fourth versus first quartile). A significant positive trend was also seen for bending/twisting. Negative associations were seen for repetitive motion and sitting.

CONCLUSIONS: Maternal occupational physical activity may be related to the etiology of orofacial clefts.