Sensitive periods for exposure to indoor air pollutants and psychosocial factors in association with symptoms of psychopathology at school-age in a South African birth cohort

Exposure to environmental toxicants and psychosocial stressors during gestation and early life are particularly harmful and may impact brain development. Specifically, exposure to indoor air pollutants (IAP) and psychosocial factors (PF) during these sensitive periods has been shown to predict childhood psychopathology. Here, we investigated sensitive periods for the individual and joint effects of IAP and PF on childhood psychopathology at 6.5 years. We analyzed data from the Drakenstein Child Health Study (N = 599). Exposure to IAP and PF was measured during the second trimester of pregnancy and 4 months postpartum. Childhood psychopathology was assessed at 6.5 years old using the Childhood Behavior Checklist (CBCL). We investigated individual effects of pre- and postnatal exposure to IAP and PF on CBCL scores using adjusted linear regression models, and joint effects of exposures using quantile g-computation and self-organizing maps (SOM). To identify possible sensitive periods, we used a structured life course modeling approach (SLCMA) as well as SOM. Prenatal exposure to IAP or PFs, and the total prenatal mixture assessed using quantile g-computation, were associated with increased psychopathology. SLCMA and SOM models also indicated that the prenatal period is a sensitive period for IAP exposure on childhood psychopathology. Depression and alcohol were associated in both the pre- and postnatal period. In conclusion, pregnancy may be a sensitive period for the effect of IAP on psychopathology. Exposure to maternal depression and alcohol in both periods was also associated with psychopathology. Determining sensitive periods of exposure is vital to ensure effective interventions to reduce psychopathology.