Maternal risk factors in the development of and risk of orofacial clefts in the Philippines

BACKGROUND: Orofacial clefts are among the most common birth defects in the world, but their etiology have not been extensively studied in non-Caucasian populations. While prior studies agree that the etiology of cleft lip +/- cleft palate is multifactorial in terms of genetics and exposures, consistent maternal risk factors have not been documented.

METHODS: As part of an epidemiologic-genetic study between Operation Smile, University of Southern California and Children’s Hospital Los Angeles, maternal and paternal history and exposures during pregnancy were collected in 2012 using interviewer-administrated questionnaires. Cases were children under age three during an Operation Smile mission in the Philippines and controls were non-cleft newborns at a local hospital. Both groups were matched for socio-economic status and education level. Univariate and multivariate logistic regression were used to compare cases and controls.

RESULTS:

49 cases and 97 controls were obtained. Industrial chemical exposure and rural residence showed in increased risk of orofacial clefting, with odds ratios of 1.6 (95% CI 0.41-6.5 p=0.04) and 3.4 (95% CI 1.6-7.3, p=0.001), respectively. Adjustments were made for maternal/paternal age, tobacco exposure and public water consumption.

CONCLUSIONS:

These findings suggest that living in rural areas and chemical exposures may contribute to the etiology of orofacial clefts. With additional studies on parental exposures in the Philippines and other southeast Asian countries, preventive measures may be implemented to reduce the incidence of orofacial clefts in this population.