Exposure to mercury at 4 years of life and associated factors in the INMA cohort in Valencia (Spain)

摘要

Background: Exposure to very high doses of mercury during vulnerable periods (such as the prenatal period or early childhood) is a risk factor for neurological development. In a previous study we observed elevated concentrations of prenatal mercury in 4 cohorts within the Spanish INMA project including the one in Valencia. In that study, mercury concentrations were associated with mother fish consumption during pregnancy. Aim: To determine hair mercury concentrations in children aged 4 years from the INMA-Valencia cohort and analyze their relation with sociodemographic factors and child's nutrition, specifically breastfeeding and fish consumption. Methods: The study population was 580 children from the INMA-Valencia cohort. Hair samples as well as child's diet frequency were collected during the visit at 4-years of age. The relationship of hair mercury concentrations in logarithm scale with fish intake at 4 years, breastfeeding, parental sociodemographic variables and cord blood mercury concentrations was analyzed using multivariate linear regression. Results:The geometric mean concentrations of mercury was 1.10 ppm (95% CI: 1.02 to 1.19), the 95th percentile was 5.13 and 5 children had concentrations above 10 ppm. Multivariate analysis showed a negative significant association (p ＜0.05) with parity and a positive one with cord blood mercury concentrations, the mother's age, and consumption of certain species offish: sword fish, white fish and canned tuna, in this order. Conclusions: The concentrations found are high in relation to the recommendations of the major regulatory agencies (WHO, EPA). Fish consumption of some species such as swordfish is the major source of exposure in our population.Children's determination of mercury in hairin the whole INMA cohort will expand the knowledge on mercury exposure among Spanish children and will allow us broadly study the associated factors and its possible role in child neurodevelopment.