Maternal factors and disparities associated with oral clefts

The epidemiology of oral clefts continually unfolds. Researchers have not reached consensus concerning the significance of maternal smoking, weight gain, diabetes, age, and education and the risk of oral clefts. The purpose of this study was to examine these factors associated with oral clefts in the US population.

The 2005 U.S. Natality Data File was utilized for this study. Bivariate analyses compared the characteristics of mothers of infants with and without oral clefts. Multivarlate analysis calculated adjusted odds ratios for various maternal characteristics overall and for each race/ethnic group.

Significant bivariate associations with oral clefts were found for maternal age, race/ethnicity, education, tobacco use, and pregnancy-associated hypertension. Multivariate models found maternal age (OR = 0.98), race/ethnicity (OR = 0.36) for non-Hispanic Blacks (OR = 0.79 for Hispanics), and tobacco use (OR = 1.66) significant after adjustment for covariates. Across all race/ethnic groups maternal age (OR = 0.98) and smoking (OR = 1.66) were significantly associated with increased risk for oral cleft (OC). Non-Hispanic Blacks and Hispanics were at lower risk for OC regardless of the presence or absence of pregnancy-associated hypertension.

Consistent with previous studies, maternal smoking was found to be associated with an increased risk of oral clefts. This association was significant for non-Hispanic Whites but not for non-Hispanic Blacks and Hispanics. A small inverse association was observed between maternal age, pregnancy-associated hypertension and the risk of oral clefts. This study confirms relationships found in previous studies but cannot establish causality. Further investigations of the risk factors for oral clefts would benefit from the study of gene-environment interactions.