title: The conjoint influence of home enriched environment and lead exposure on children's cognition and behaviour in a Mexican lead smelter community.
abstract: A range of studies has been conducted on the detrimental effects of lead in mining and smelting communities. The neurocognitive and behavioural health effects of lead on children are well known. This research characterized the conjoint influence of lead exposure and home enriched environment on neurocognitive function and behaviour for first-grade children living in a Mexican lead smelter community. Structural equation models were used for this analysis with latent outcome variables, Cognition and Behaviour, constructed based on a battery of assessments administered to the first-grade children, their parents, and teachers. Structural equation modelling was used to describe complex relationships of exposure and health outcomes in a manner that permitted partition of both direct and indirect effects of the factors being measured. Home Environment (a latent variable constructed from information on mother's education and support of school work and extracurricular activities), and child blood lead concentration each had a main significant effect on cognition and behaviour. However, there were no statistically significant moderation relationships between lead and Home Environment on these latent outcomes. Home Environment had a significant indirect mediation effect between lead and both Cognition and Behaviour (p-value<0.001). The mediation model had a good fit with Root Mean Square Error of Approximation <0.0001 and a Weighted Root Mean Square Residual of 0.895. These results were highly significant and suggest that Home Environment has a moderate mediation effect with respect to lead effects on Behaviour (β=0.305) and a lower mediation effect on Cognition (β=0.184). The extent of home enrichment in this study was most highly related to the mother's support of schoolwork and slightly less by the mother's support of extracurricular activities or mother's education. Further research may be able to develop approaches to support families to make changes within their home and child rearing practices, or advocate for different approaches to support their child's behaviour to reduce the impact of lead exposure on children's cognitive and behavioural outcomes.
authors.affiliation: Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States. moodie.sue@gmail.com
authors.forename: Sue
authors.initials: S
authors.lastname: Moodie
authors.forename: Nick
authors.initials: N
authors.lastname: Ialongo
authors.forename: Patricia
authors.initials: P
authors.lastname: López
authors.forename: Jorge
authors.initials: J
authors.lastname: Rosado
authors.forename: Gonzalo
authors.initials: G
authors.lastname: García-Vargas
authors.forename: Dolores
authors.initials: D
authors.lastname: Ronquillo
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kordas
mesh_terms: D001822:Body Burden; D016009:Chi-Square Distribution; D002648:Child; D002652:Child Behavior / Q000187:drug effects*; D002657:Child Development / Q000187:drug effects; D002668:Child Rearing; D002675:Child, Preschool; D003071:Cognition / Q000187:drug effects*; D003430:Cross-Sectional Studies; D004522:Educational Status; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000097:blood; D006801:Humans; D007854:Lead / Q000009:adverse effects* / Q000097:blood; D020264:Lead Poisoning, Nervous System, Childhood / Q000097:blood / Q000209:etiology* / Q000523:psychology; D016015:Logistic Models; D008669:Metallurgy; D008800:Mexico; D008906:Mining; D009034:Mother-Child Relations; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D012111:Residence Characteristics; D012944:Social Support
chemical_list: D004785:Environmental Pollutants; D007854:Lead