Prenatal chemical exposures, childhood adversity, resilience and risk of depression

Depression is the leading cause of mental-health related morbidity worldwide and approximately 19.4 million US adults and 3.8 million US adolescents are affected annually. Emerging evidence suggests that prenatal exposure to legacy (polybrominated diphenyl ethers, PBDEs) and replacement (organophosphate esters, OPEs) flame retardant chemicals increase the risk of maternal postpartum depression and symptoms of depression in young children. Despite widespread evidence of their neurotoxic effects and endocrine disrupting potential, there are limited studies investigating impacts of PBDEs/OPEs on mental health outcomes, and there have been no studies that have investigated effects of PBDE/OPE mixtures on depression. We hypothesize that higher prenatal exposure to OPEs and PBDEs is associated with altered maternal depression trajectories in the first eight postpartum years and with greater symptoms of depression in childhood (age 6-8). We also hypothesize that childhood adversities, resilience and familism may be important modifying factors for PBDE/OPE exposure effects on maternal depression trajectories and childhood depressive symptoms. We propose to investigate the following specific aims in 500 mother-child pairs participating in the MADRES cohort in Los Angeles. Aim 1 will investigate individual and joint effects of prenatal exposure to PBDEs and OPEs with maternal depression trajectories from pregnancy through eight years postpartum. Aim 2 will investigate individual and joint effects of prenatal exposure to PBDEs and OPEs and early childhood OPEs with parent- and child-reported depressive symptoms at ages 6-8 and will examine whether these relationships differ by child sex and maternal depression. Aim 3 will examine the modifying roles of maternal and child exposure to adversities, maternal resilience and maternal-reported familism on the associations between OPE/PBDEs and maternal depression trajectories and child depressive symptoms at ages 6-8. As exposures to environmental chemicals and mental health outcomes disproportionately impact pregnant women, it is an urgent priority to understand the contribution of modifiable risk factors to develop effective public health intervention and prevention strategies.