Gender difference in the effects of lead exposure at different time windows on neurobehavioral development in 5-year-old children

Although the association between lead exposure and children's neurodevelopment has been studied, gender differences remain to be investigated. We examined the effects of lead exposure on the neurobehavioral development of 5-year-old children to identify the vulnerable time window of exposure and potential gender difference. A total of 1751 pregnant women and children participated in the prospective birth cohort study, Mothers and Children's Environmental Health study, since 2006. Lead levels were measured in the maternal blood in early and late pregnancies, in cord blood at birth, and in 2-, 3-, and 5-year-old children's blood. The behavior of 575 children aged 5years were assessed using the Korean Child Behavior Checklist. The association between the blood lead level at each time window and behavior was examined using a generalized linear model adjusted for potential confounders and covariates. Lead levels at late pregnancy were significantly associated with increased risk of behavioral problems in males. Lead levels in 2- and 5-year-old children's blood significantly increased behavioral risks in females: for a 1-μg/dL increase in blood lead levels, the score for total behavioral problems increased by 3.00 (95% confidence interval [CI]: 0.56–5.45) during the late pregnancy in males, whereas it increased by 3.82 (95% CI: 1.25–6.39) at 2years and by 5.72 (95% CI: 0.44–10.99) at 5years in females with a stronger effect in attention and sleep problems. Effects of lead toxicity on children's neurobehavioral development showed gender differences. Males were more susceptible to prenatal exposure, while females were more susceptible to postnatal exposure with stronger effects in attention and sleep problems. [Display omitted] •Appreciation on gender differences is useful for understanding the mechanism underlying neurodevelopmental toxicity.•Behavioral problems in 5-years’ children were examined in association with blood lead levels from prenatal to 5years.•Behavioral problems significantly increased by increase of lead exposure at prenatal in male while at postnatal in female.•Females with postnatal lead exposure showed a stronger association in attention and sleep problems than males.