Milk is a good source of fats, minerals, and vitamins. The present prebirth cohort study examined the association between maternal dairy product intake during pregnancy and the risk of childhood behavioral problems in 5-year-old Japanese children. Study subjects were 1199 mother–child pairs. Dietary intake was assessed using a diet history questionnaire. Emotional problems, conduct problems, hyperactivity problems, peer problems, and low prosocial behavior were assessed using the parent-reported version of the Strengths and Difficulties Questionnaire. Adjustments were made for a priori selected non-dietary confounders and potentially related dietary factors. A significant inverse exposure–response association was observed between maternal total dairy intake during pregnancy and the risk of childhood emotional problems (adjusted odds ratio [OR] between extreme quartiles, 0.62; 95% confidence interval [CI]: 0.36–1.03, p for trend, 0.04). The greater maternal consumption of cow’s milk, but not yogurt or cheese, during pregnancy was independently related to a reduced risk of emotional problems in children (adjusted OR between extreme quartiles, 0.41; 95% CI: 0.23–0.70, p for trend, 0.003). Higher maternal consumption levels of total dairy products, especially cow’s milk, during pregnancy may be associated with a decreased risk of emotional problems in 5-year-old children.

In recent years, more attention has been paid to behavioral problems in children. However, for the most part, risk factors for these problems have yet to be determined. The current prebirth cohort study investigated the relationship between maternal calcium consumption during pregnancy and behavioral problems in five-year-old Japanese children. Subjects were 1199 mother-child pairs. Dietary intake was assessed using a diet history questionnaire. Emotional problems, conduct problems, hyperactivity problems, and peer problems were assessed using the Strengths and Difficulties Questionnaire. Logistic regression analysis was conducted to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for four behavioral problems under study according to the quartile of calcium intake, with the lowest quartile as the reference. Adjustment was made for maternal age, gestation at baseline, region of residence at baseline, number of children at baseline, maternal and paternal education, household income, maternal depressive symptoms during pregnancy, maternal alcohol intake during pregnancy, maternal smoking during pregnancy, child's age, child's birth weight, postnatal secondhand smoke exposure at home during the first year of life, and breastfeeding duration. Higher maternal calcium intake during pregnancy was independently associated with a decreased risk of childhood emotional and hyperactivity problems; the adjusted ORs between extreme quartiles (95% CIs, P for trend) were 0.46 (0.27–0.79, 0.01) and 0.60 (0.37–0.97, 0.046). No such inverse associations were observed for childhood conduct problems or peer problems. Maternal calcium intake during pregnancy may decrease the risk of childhood emotional and hyperactivity problems.