Gender-specific effects of prenatal mixed exposure to multiple serum phthalates on neurodevelopment of children aged 2-3 years ： the Guangxi Birth Cohort Study

Abstract Phthalates have been shown to have adverse effects on neurodevelopment, which may be gender-specific. However, the association between prenatal mixed exposure to phthalates and children's neurodevelopment remain limited. We measured prenatal phthalate levels and children's neurodevelopment. Logistic regression was fitted to examine the association. Among boys, mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) has adverse effects on gross motor (OR: 7.39, 95% CI:1.42, 38.5). For gross motor in boys, joint effect was discovered between mono-2-ethylhexyl phthalate (MEHP) and MEHHP. Moreover, synergistic effects were found for MEHP with vanadium and cadmium, and antagonistic effects for MEHP with magnesium, calcium, titanium, iron, copper, selenium, rubidium and strontium. We did not find statistically significant relationships in girls. In the 1st trimester, adverse effects were identified between mono-2-ethyl-5-oxoyhexyl phthalate (MEOHP) and adaptation ( P = 0.024), and monomethyl phthalate (MMP) with social area ( P = 0.016). In the 2nd trimester, the risk of social development increased with MEHHP. In summary, we found boys may be more vulnerable to the neurotoxicity than girls in gross motor, and the 1st and 2nd trimester might be more sensitive in terms of phthalates on children. To some extent, supplementation of the appropriate metals in the 1st trimester may reduce or inhibit the absorption of phthalates by the foetus, especially in males, so as to prevent neurodevelopmental impairment.