Maternal tobacco smoking, obesity, and low socioeconomic status during early pregnancy in the etiology of esophageal atresia.

BACKGROUND: The etiology of the congenital malformation esophageal atresia (EA) is essentially unknown. We hypothesized that maternal tobacco smoking, obesity, and low socioeconomic status (SES) during early pregnancy might increase the risk of the fetus developing EA.
METHODS: A nationwide, population-based, case-control study was nested in a cohort of children born in Sweden in 1982 to 2004. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using logistic regression. Matching, stratification, and multivariable regression were used to control for confounding.
RESULTS: Among 2,305,858 newborn children constituting the study cohort, 722 cases of EA and 3610 controls were included. For women smoking 10 cigarettes or more daily, the adjusted OR was 0.88 (95% CI, 0.62-1.25) compared to nonsmokers. For obese women (body mass index, >30), OR was 0.99 (95% CI, 0.64-1.55) compared to lean women (body mass index, <20). Women with more than 12 years of formal education, representing SES, had an OR of 0.94 (95% CI, 0.69-1.29) compared to those with less than 10 years of education. The lack of association remained in stratified analyses of isolated EA and EA accompanied by associated malformations.
CONCLUSION: This study provides evidence refuting the hypotheses of an increased risk of EA among children of women who smoke, are obese, or have a low SES during early pregnancy.