Iron deficiency and cognitive impairment in children with low blood lead levels

Sana Maidoumi; Charif Radouan Ouaziz; Mariam Ouisselsat; Amal El Maouaki; Mohamed Loukid; Nadra Lekouch; Alain Pineau; Ahmed Ahami; Azeddine Sedki

doi:10.1016/j.toxrep.2022.08.008

Iron deficiency and cognitive impairment in children with low blood lead levels

Toxicol Rep. 2022 Aug 23:9:1681-1690. doi: 10.1016/j.toxrep.2022.08.008. eCollection 2022.

Authors

Sana Maidoumi¹, Charif Radouan Ouaziz¹, Mariam Ouisselsat¹, Amal El Maouaki¹, Mohamed Loukid², Nadra Lekouch¹, Alain Pineau³, Ahmed Ahami⁴, Azeddine Sedki¹

Affiliations

¹ Laboratory of Water, Biodiversity and Climate Change, Department of Biology, Faculty of Sciences - Semlalia, Cadi Ayyad University, Bd: Moulay Abdellah BP, 2390-40001 Marrakech, Morocco.
² Laboratory of Pharmacology, Neurobiology, Anthropobiology, Environment, and Behabiour, Department of Biology, Faculty of Sciences - Semlalia, Cadi Ayyad University, Bd: Moulay Abdellah BP, 2390-40001 Marrakech, Morocco.
³ Mineral Element Dosing Centre, UFR of Pharmaceutical and Biological Sciences, University of Nantes, 9, rue Bias, 44035 - 44000, Nantes Cedex 1, France.
⁴ Laboratory of Biology and Health, Unit of Neurosciences and Nutrition, Department of Biology, Faculty of Sciences, Ibn Tofail University, Bd: 133, Kenitra, Morocco.

Abstract

Background: The relationship between iron deficiency (ID) and children's neurocognitive functions has attracted the interest of the scientific community, particularly among those living at the lead-contaminated sites. Thus, the current paper aims at evaluating the association between ID and neurocognitive performance of school children living in a mining area (CMA) in comparison with a control group (CG).

Methods: he study involves 90 school children aged from 6 to 10 years old. A survey was conducted to obtain information on the socio-economic and demographic status of the children. The students underwent cognitive test battery including the Bell Dam Test (BDT) and the Digit Span test (DST). Iron status (IS) was determined by serum iron, ferritin, transferrin, and blood count (CBC). Blood lead levels (BLLs) were measured by the Graphite Furnace Atomic Absorption Spectrophotometer (SAA-FG).

Results: An ID was observed in 23.3 % of CMA, but it is not statistically different from the CG 21.7 % (p = 0.774). CMA group exhibited elevated BLLs (3.5 ± 1.21 µg/dL) when compared to the CG (2.31 ± 0.95 µg/dL), p = 0.006. Children's performance on the visual attention test (VA) was impaired in both groups. Working memory (WM) abilities were normal. In bivariate analysis, no difference was demonstrated in mean BLLs between the students who adopt the disorganized scanning strategy compared to the others whose method is organized for both CMA (t = - 0.508, p = 0.616) and CG (t = - 0.014, p = 0.989). Multivariate models did not reveal any association between IS and cognitive scores of children in the two groups (p > 005). Nevertheless, daily milk consumption was positively associated to VA skills among CMA. A negative influence of BLLs above the threshold value of 5 µg/dL was determined on children's WM skills.

Conclusion: Our results suggest that low-level lead exposure did not influence children's visual attention scores but may adversely affect WM abilities if it reaches the threshold value of 5 µg/dL regardless of their IS.

Keywords: BDT, bell dam test; BLLs, blood lead levels; BMI, body mass index; Blood lead level; CBC, blood count; CG, control group; CMA, children in a mining area; Children; Cognitive impairment; DST, digit span test; ID, Iron deficiency; IS, iron status; Iron deficiency; SAA-FG, graphite furnace atomic absorption spectrophotometer; VA, visual attention; WM, working memory.