Prenatal Low Levels Mercury Exposure on Infant Development: A Prospective Study in Zhoushan Islands, China

Abstract

ISEE-505 Objective: To explore the relationship between prenatal mercury exposure and infant neurodevelopmental outcomes in Zhoushan cohort. Material and Methods: Four hundred eight mother-infant pairs were enrolled in the cohort of Zhoushan Islands. Prenatal mercury exposure was determined by measuring cord blood mercury (CBHg, range 1.34–18.34 μg/L). On the basis of their CBHg, children were divided into 2 groups: 80 in low mercury group (LG, CBHgP80, 8.09 μg/L). Children were followed up at 3 (n = 149) and 12 (n = 123) months of age with evaluated BSID, hair mercury, and questionnaire. The association between CBHg and neurodevelopmental outcomes at 3 and 12 months of age was examined by multiple regression analysis with adjustment for confounding variables. Results: The average hair mercury levels were 1058.71 ± 69.58 (LG), 1903.06 ± 139.37 μg/kg (HG) of 3-month-infant and 906.05 ± 110.26 (LG), 1512.41 ± 93.85 μg/kg (HG) of 12-month-infant. The hair mercury of 12-month were lower than that of 3-month significantly in both group. MDI of 3-month-infant were 109.01 ± 4.16 of LG, 108.32 ± 4.23 of HG, PDI were 99.91 ± 3.28 of LG, and 98.71 ± 5.21 of HG. MDI of 12-month-infant were 110.60 ± 4.29 of LG, 109.56 ± 4.29 of HG; PDI were 104.06 ± 3.75, and 101.70 ± 3.59 of HG. There were no significant differences of MDI and PDI between the 2 groups in both ages. At 3 months, high risk factors for MDI were hair mercury of 3 months and head circumference; and those for PDI were hair mercury of 3 months and gender. At 12 months, the high risk factors for MDI scores were hemoglobin of 3 months, age when children stood up and those for PDI were age when children stood up, average times of fish dinners of mother and hemoglobin of 12 months. Conclusions: The hair mercury level was significantly related with CBHg. The mercury exposure level of 12-month-infant was lower than that of 3-month-infant. Prenatal low level mercury exposure of Zhoushan cohort had no significantly impacts on infants' development.