This study attempted to learn the association between maternal betaine-homocysteine methyltransferase (BHMT) gene polymorphisms, maternal dietary habits, and their interactions with the risk of ventricular septal defects (VSD) in offspring. A total of 426 mothers of VSD children and 740 control mothers were included in the study. Logistic regression was used to evaluate the level of associations and interaction effects. Our study suggested that mothers reporting excessive intake of smoked foods (aOR = 2.44, 95%CI: 1.89-3.13), barbecued foods (aOR = 1.86, 95%CI: 1.39-2.48), fried foods (aOR = 1.93, 95%CI: 1.51-2.46), and pickled vegetables (aOR = 2.50, 95%CI: 1.92-3.25) were at a significantly higher risk of VSD in offspring, instead, mothers reporting regular intake of fresh fruits (aOR = 0.47, 95%CI: 0.36-0.62), fish and shrimp (aOR = 0.35, 95%CI: 0.28-0.44), fresh eggs, (aOR = 0.56, 95%CI: 0.45-0.71), beans (aOR = 0.68, 95%CI: 0.56-0.83), and milk products (aOR = 0.67, 95%CI: 0.56-0.80) were at a lower risk of VSD in offspring. In addition, maternal BHMT gene polymorphisms at rs1316753 (CG vs. CC: aOR = 2.01, 95%CI: 1.43-2.83) and rs1915706 (CT vs. TT: (aOR = 1.81, 95%CI: 1.33-2.46) were significantly associated with increased risk of VSD in offspring. Furthermore, a significant interaction between BHMT polymorphisms and maternal bean intake was identified in the study. In conclusion, Maternal BHMT polymorphisms at rs1316753 and rs1915706, dietary habits as well as their interaction were observed to be significantly associated with the risk of VSD in offspring.
Keywords: BHMT gene plolymorphisms; dietary habits; interaction effects; ventricular septal defects.