Impact of methylmercury and other heavy metals exposure on neurocognitive function in children of 7 years old: study protocol of the follow-up

Background. The extent to which prenatal low-level mercury (Hg) exposure through maternal fish intake and heavy metals exposure affect children neurodevelopment is controversial and may appear in long term. In 2007 a prospective cohort, the Northern Adriatic Cohort II (NAC-II), was established to investigate the association between prenatal Hg exposure from maternal fish consumption and child neurodevelopment. 900 pregnant women were enrolled. 632 and 470 children underwent neurodevelopmental evaluation, respectively, at 18 and 40 months of age. The NAC-II cohort is a part of the Mediterranean cohort in “Public health impact of long-term, low-level, mixed element exposure in susceptible population strata” project. Methods. This protocol describes the follow-up assessment of the effects of prenatal low level Hg and other heavy metals exposure on the developing nervous system of the children born within the NAC-II and reached the age of 7 years. Child diet components are estimated through a Diet Diary. Child hair and urine are collected for determination of Hg level. In addition, levels of other potentially neurotoxic metals, namely Manganese, Cadmium, Lead, Arsenic and Selenium are also measured in the same matrices. Discussion. This protocol extends to the first years of schooling age the evaluation of the neurotoxicant effect of Mercury and of the other heavy metals on children’s neurodevelopment, adjusting for the potential confounders such as the lifestyles and the social economic status of children’s families. Longitudinal analysis of neurodevelopment, assessed in different ages (18, 40 months and 7 years), are performed.