Habilidades intelectuais e suas interfaces neurocognitivas em crianças e adolescentes expostos ao mercúrio

Abstract

Introduction: Mercury (Hg) is an element categorized within the group of so-called "heavy metals" being a grayish compound and liquid at room temperature. Exposure to Hg (E-Hg) occurs as a result of anthropogenic action by the development of activities that lead to the exploitation of natural resources which end up generating a burden on the environment that subsequently reaches the human being as a result of their interaction. Objective: to investigate the association between intellectual performance and neurocognitive interfaces and their relationship with mercury exposure. Methods: The participating subjects were 62 Colombian children and adolescents between 6 and 14 years of age from the departments of Antioquia and Chocó, divided into two study groups and matched under the same sociodemographic conditions (N=31 case and N=31 control). The instruments used for data collection were: 1) the Wechsler Intelligence Scale for Children (WISC V), 2) biological samples were taken as reference for measuring the level of exposure to Hg through biomarkers in blood (BS), hair (BC) and urine (BU). Results: From the comparison analyses between groups, statistically significant differences (p<0.05) were found in most of the intellectual measurements studied (with the exception of the WISC Span of W-SD drawings), as well as, a large effect size (d) and a broad statistical power (1- β) in nine of the fifteen differences found (>0.80); these differences were even greater in the range between 9 and 11 years. Regarding bivariate correlation analysis, significant negative associations were found in thirteen of the sixteen total measurements that related the levels of Hg in hair (HgC) and/or Hg in blood (HgS) and with variables such as age and frequency of fish consumption. In multiple linear regression analyses, decreases in intellectual/neurocognitive ability scores were found as a function of increased E Hg levels in hair and blood, once sociodemographic covariates were adjusted. Conclusions: The results found confirm the probabilistic hypothesis that E-Hg in children and adolescents has an interference effect associated with the manifestation of inferior performance in the studied abilities.