[Impact of antioxidant vitamins and heavy metal levels at birth on neurodevelopment of children assessed at two years of age].

OBJECTIVE: Epidemiologic study on the perinatal interaction of antioxidant vitamins and heavy metals on offspring's intellectual development is extremely limited. The aim of this prospective cohort study was to investigate the status of maternal and cord blood antioxidant vitamins (Vitamin A, E and C) and heavy metals (lead, cadmium and mercury) at delivery and correlations between these antioxidant vitamins or metals and neurodevelopment of early childhood, and to explore the protective effect of antioxidant vitamins against the injure of heavy metals to intellectual development in children in Tongliang, Chongqing, China.

METHOD: A total of 150 pairs of mothers-neonates were recruited. Serum concentrations of vitamin(V) A, vitamin E, vitamin C, lead, cadmium and mercury in maternal and cord blood after delivery were determined and intellectual development was evaluated by Gesell Development Schedule (GDS) at two years of age.

RESULT: A total of 111 pairs of maternal-neonatal subjects with completed data were included into statistical analysis. After adjusting for potential confounders, cord blood mercury level was found negatively associated with all the development quotients (DQs) (β = -0.486, β = -0.716, β = -0.846, β = -0.935, β = -0.702, P < 0.05). Cord VE level was positively correlated with motor, adaptation, language and average DQ (β = 0.475, β = 0.458, β = 0.403, β = 0.395, P < 0.05). When antioxidant vitamins and heavy metals levels were all included into the multiple regression model, cord vitamin E level was statistically positively related with motor, adaptation and average DQs (β = 0.449, β = 0.412, β = 0.349, P < 0.05). While cord blood mercury level was negatively correlated with adaptation, language, social and average DQ (β = -0.397, β = -0.727, β = -0.935, β = -0.628, P < 0.05), the relationship between cord mercury level and motor DQ was not statistically significant (P = 0.0890). The motor, adaptation, language and average DQs in high cord VE group were higher than those in low VE group (t = 2.93, t = 2.06, t = 2.13, t = 2.27, P < 0.05). Social DQ in high cord lead group was significantly lower than that in low lead group (χ(2) = 5.56, P = 0.015). Cord VC level in high cadmium group was significantly lower than that in low cadmium group (χ(2) = 7.62, P = 0.006). VA placental transport ratio in high mercury group was significantly lower than those in low mercury group (χ(2) = 8.02, P = 0.005).

CONCLUSION: Our data suggested that there may be certain interaction between antioxidant vitamin A, E, C and heavy metals lead, cadmium, mercury. Antioxidant vitamins at delivery may have protective effect on the early neurodevelopment via interaction with the heavy metals.