Maternal and Paternal Occupations and Cleft Lip and Cleft Palate in Offspring

Abstract

Oral clefting is defined as a fissure in the midline of the palate so that the two sides fail to fuse during embryonic development; in some cases, the fissure may extend through both the hard and soft palates into the nasal cavity. Several studies have found an association between maternal and paternal occupations and risk of oral clefts in offspring. This study explored whether an association existed between maternal and paternal occupation and oral clefts in offspring among 563 births with oral clefts and 1386 births without any congenital malformations. The study population was Texas children born in 2000. The following maternal occupations: dental assistants, hairdresser, leather shoe repairer, nurse, retail sales worker, and surgical technologist; and the following paternal occupation: automobile mechanic, farmer, leather shoe repairer, and painter were studied for their possible association with oral clefts in offspring. These occupations were selected because previous studies have found an association between these occupations and oral clefts in offspring. Descriptive statistics (frequencies and crosstabs) and logistic regression were used to analyze the data in SPSS version 11.0. No associations were found in the following occupations: maternal hairdresser (odds ratio 1.5, 95% Cl 0.3, 6.2), maternal nurse (odds ratio 1.6, 95% Cl 0.8, 3.3), paternal automobile mechanic (odds ratio 0.8, 95% Cl 0.4, 1.6), and paternal painter (odds ratio 0.3, 95% Cl 0.1, 1.4). Elevated odds ratios were found in the following occupations: maternal dental assistant (odds ratio 2.1, 95% Cl 0.3, 15.2), paternal farmer (odds ratio 1.9, 95% Cl 0.4, 8.7) and maternal retail sales workers (odds ratio 2.0, 95% Cl 1.0, 4.1). For all of these occupations, the 95% confidence intervals for the odds ratios included 1.0 indicating no significant association between having those occupations and having a child with an oral cleft. Also, smoking was a statistically significant risk factor for oral clefts in offspring (odds ratio 2.5, 95% Cl 1.8, 3.7, p < 0.05). Several occupational groups of interest had no case or control parents so these could not be studied. Those occupations included: maternal leather shoe repairer, maternal surgical technologist and paternal leather shoe repairer. In conclusion, this study did not find any statistically significant associations between maternal and paternal occupations and oral clefts in offspring. However, maternal smoking was a significant risk factor for oral clefts in this population.