Sociodemographic and lifestyle characteristics of mothers, fathers and children.

aQuantitative data and categorical data were expressed as mean ± SD and n (%), respectively.bMann-Whitney U test was used to compare means; chi-square test was used to compare proportions and Fisher’s Exact Test was also used if not matched. A 2-tailed p value was chosen as the level of significance.cBody mass index(BMI) was calculated as weight divided by height (m) squared and it was divided into 4 categories: underweight ([28], [29].dThe periconceptional period was defined as 4 weeks prior to conception until the end of first trimester. The maternal use of folic acid in the periconceptional period was defined as the daily use of at least 400 ug folic acid during the complete periconceptional period. In consistent users were classified as non-users. We defined smoking, alcohol consumption, tea-drinking, coffee-drinking and medication use as any use during the periconceptional period.