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Postnatal exposure to mercury and neuropsychological development among preschooler children


The objective of this study was to describe the postnatal exposure to Hg and to evaluate its association with neuropsychological development among preschool children. The study population are 4–5 years old children (n = 1252) participant in the Spanish INMA Project. Total Hg was measured in cord blood and in hair samples taken at 4 years of age (2008–2012). Neuropsychological development was assessed using the McCarthy Scales of Children’s Abilities (MSCA). Information on covariates and possible confounders was obtained by questionnaires during pregnancy and childhood. Generalized additive and linear regression models were built in order to assess the relationship between MSCA scores and Hg exposure. We also evaluated the magnitude of the possible bias generated from measurement error in seafood intake estimate from questionnaire and Hg determination. The geometric mean of hair Hg was 0.98 µg/g [95% confidence interval (CI) 0.94, 1.03]. In the regression analysis, the association between Hg and the MSCA scores was positive for all the scales and statistically significant for the verbal (β = 0.89; 95%CI 0.38, 1.39), memory (β = 0.42; 95%CI 0.09, 0.76) and general cognitive scales (β = 1.35; 95%CI 0.45, 2.25). However, these associations were clearly attenuated when we adjusted by the children’s fish intake variables or when took into account theoretical scenarios of low precision in fish intake and Hg measurements. Hg levels in this Spanish population were high in comparison with other European countries; however, we did not observe adverse effects on child neuropsychological development associated with this postnatal exposure to Hg.

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The authors would particularly like to thank all the participants for their generous collaboration. A full roster of the INMA Project Investigators can be found at


This study was funded by grants from European Union (FP7-ENV-2011 cod 282957 and HEALTH.2010.2.4.5-1), Spain: Instituto Carlos III (Red INMA G03/176; CB06/02/0041; FIS-FEDER: PI03/1615, PI04/1509, PI04/1436, PI04/1112, PI04/1931, PI05/1079, PI05/1052, PI06/0867, PI06/1213, PI07/0314, PI081151, PI09/00090, PI09/02647, PI11/01007, PI11/02591, PI11/02038, PI12/00610, PI13/02187, PI13/1944, PI13/2032, PI14/00108, PI14/00891, PI14/01687, PI16/00261, PI16/1288, PI17/00663, and PI19/1338; Miguel Servet-FSE: MS11/0178, MS15/0025, MSII16/0051, MSII19/00015; Miguel Servet-FEDER: CP11/0178 and CP15/0025, co-funded by European Regional Development Fund ‘A way to make Europe’), CIBERESP, Generalitat de Catalunya (CIRIT 1999SGR 00241 and AGAUR 2009 SGR 501), Fundació La marató de TV3 (090430), EU Commission (261357), Generalitat Valenciana, FISABIO (UGP 15-230, UGP-15-244, and UGP-15-249), Department of Health of the Basque Government (2005111093, 2009111069, 2013111089 and 2015111065), the Provincial Government of Gipuzkoa (DFG06/002, DFG08/001 and DFG15/221), annual agreements with the municipalities of the study area (Zumarraga, Urretxu, Legazpi, Azkoitia y Azpeitia y Beasain), and Alicia Koplowitz Foundation 2017. ISGlobal is a member of the CERCA Programme, Generalitat de Catalunya.

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Correspondence to Sabrina Llop.

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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (Hospital La Fe in Valencia, the Institut Municipal d’Assistència Sanitaria in Barcelona, Comité Ético de Investigación Clínica del Hospital Donostia, and Comité Ético de Investigación Clínica del Área Sanitaria de Gipuzkoa) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

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Llop, S., Murcia, M., Amorós, R. et al. Postnatal exposure to mercury and neuropsychological development among preschooler children. Eur J Epidemiol 35, 259–271 (2020).

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  • Methylmercury
  • Cognitive
  • Development
  • Postnatal
  • Fish