Associated prenatal factors of behavioral and emotional problems in 5 year-old children: The Hokkaido Study

Abstract

Introduction: Prenatal environment is considered to contribute childhood development and behavior. The aim of this study was to evaluate prenatal environmental factors including chemical exposures and socio-economic status which were associated with increased risk of child behavioral and emotional difficulties. Methods: 3813 Japanese version of parent report Strength and Difficulty Questionnaire (SDQ) were distributed to the subpopulation of prospective birth cohort study as a follow-up study at 5 year of age between Oct. 2014 and Dec, 2015. Total difficulties score (TDS) and scores of five subscales were examined. Maternal smoking, drinking and BMI, parental age, education, family income were obtained from baseline questionnaire. Birth weight, infant sex and gestational age were obtained from birth record. Maternal BPA and phthalates levels were measured to assess prenatal exposure to environmental chemicals. Results: The response rate was 67.1%. 2553 valid response were included into the analysis. The mean TDS was 8.73 ± 5.06 and boys showed significantly higher TDS compared to girls (P < 0.001). 20.4% (N=284) of children were above cut-off (TDS ≧ 13). Factors that increased the risk of having overall behavioral and emotional difficulties were; lower parental education levels, younger parental age, lower family income, higher maternal BMI, maternal smoking, being a boy and first child. Especially family income was strong contributing factor of each subscale except prosocial behavior. Maternal drinking, birth weight and gestational age were not associated. Maternal BPA level was significantly higher among children above TDS cut-off value (P = 0.012). Phthalate levels were no significantly different. Conclusion: This study found significant contributing factors of increased risk of child behavioral and emotional difficulties. Prenatal BPA exposure may be associated with behavioral and emotional problems in 5 year-old children.