Risk factors for neural tube defects: a study at university-affiliated hospitals in Tehran

Neural tube defects have a complex and imperfectly understood etiology involving both genetic and environmental factors. In this case-control study, we tried to determine the association of known risk factors for neural tube defects in patients referred to university-affiliated hospitals with neurosurgical services in the city of Tehran. Risk factors were assessed in-person through interviews with infants' mothers. We found 192 neural tube defect cases. One hundred and ninety-three apparently normal babies were randomly selected from the same hospitals to serve as control cases. Maternal age of less than 18 years (P = 0.02), female sex of the child (P = 0.01), birth in spring and summer seasons (P = 0.001), history of not using folic acid (P = 0.001), less than 5 prenatal visits (P = 0.001), and poverty (P = 0.02) were the most important risk factors for neural tube defects. Logistic regression analysis of these risk factors confirmed these correlations. A negative history of consuming folic acid had the most significant statistical correlation with these malformations. Poor quality diets were an important environmental risk factor in this study.