# Socio-Emotional, Behavior and Cognitive Disorders Associated with Exposure to Trace Metals: A Cross-Sectional Pilot Study in School-Age Children in Haut-Katanga Province

## TL;DR

This study explores how exposure to trace metals in children in Haut-Katanga Province is linked to cognitive and behavioral issues, finding higher problems in rural areas and associations with metal exposure.

## Contribution

This is the first cross-sectional study in Haut-Katanga Province examining trace metal exposure and its impact on children's socio-emotional and cognitive development.

## Key findings

- Rural children showed higher behavioral difficulties compared to urban children.
- Urban children performed better in cognitive tasks like facial affect recognition and inhibitory control.
- Elevated trace metal levels in urban areas correlated with behavioral and cognitive issues.

## Abstract

Introduction: Trace metals can negatively impact biological functions and brain development. Cognitive and neurobehavioral disorders in children are poorly documented in Haut-Katanga Province, an area with significant and multiple exposures to trace metals that can lead to the exacerbation of cognitive and behavioral disorders. Objective: This study aimed to characterize the behavior of schoolchildren linked to their cognitive performance in urban and rural environments. Methods: A cross-sectional pilot study was conducted on 52 schoolchildren aged 6 to 11 (22 from rural areas presumed less exposed to metals and 30 from Lubumbashi, DRC). This study employed NEPSY-II tests, the Strengths and Difficulties Questionnaire (SDQ-Tutor), ENA 2020 software and trace metal spectrometry assays. Statistical tests were carried out with SPSS-20 and Stata-18. Results: Our findings revealed a correlation between children’s malnutrition and low mother’s education. The “total difficulties score” was more prevalent in rural areas (73%) compared to urban settings (37%) p < 0.05), in contrast to the “negative impact of difficulties” (59% versus 57%, p > 0.05). Urban children demonstrated superior cognitive performance, particularly in “facial affect recognition” (8 versus 4, p = 0.013) and “inhibitory control” (6.5 versus 3, p = 0.032). As-U(urine), Cd-B(blood), Hg-B, Mo-U, Ni-U, Pb-U, Pb-B and Sb-U were elevated compared to references. In general, urban areas had higher metal levels than rural areas. Blood and urine metals showed a complex and significant relationship with behavioral difficulties or cognitive performance. Conclusions: The observed behavioral issues, cognitive performance deficits and their association with nutritional deficiencies and trace metal exposure suggest a multifactorial neurodevelopmental origin. These findings highlight the need for further research in the region.