Infant cognitive home environment as a moderator for the association of prenatal lead on child language

Exposure to lead during early life, including in pregnancy, is toxic to neurodevelopment. Though public health initiatives have resulted in an overall reduction in lead exposure levels, lead remains a significant environmental hazard, requiring innovative efforts to mitigate the burden of early life lead. This study explored whether positive postnatal social experiences in the forms of positive caregiving and a rich cognitive home environment moderate the associations of prenatal lead on child neurodevelopmental outcomes including language skills, effortful control, and executive function skills. We leverage an analytic sample (N = 107) drawn from a prospective cohort of mother-infant dyads. Prenatal lead was measured from maternal urine, positive caregiving from observational methods, and cognitive home environment from a validated questionnaire. Results reveal a negative association of prenatal lead on child language when the cognitive home environment in infancy was poor (β=-0.32, p = 0.04) but not when the cognitive home environment in infancy was rich (β=0.20, p = 0.16). This buffering effect was not observed for the child outcomes of effortful control or executive function skills. Our results encourage future research into the provision of a rich cognitive home environment as a means of mitigating the detrimental effects of prenatal lead exposure on early child language skills.