Mercury and Autism Spectrum Disorder: Exploring the Link through Comprehensive Review and Meta-Analysis

Area of Science:

• Neuroscience
• Environmental Health
• Pediatrics

Background:

• Mercury (Hg) is a neurotoxicant with known adverse effects on the central nervous system.
• Autism spectrum disorder (ASD) is a complex neurodevelopmental condition.
• Understanding environmental factors, such as Hg exposure, is crucial for ASD research.

Purpose of the Study:

• To conduct a comprehensive meta-analysis of Hg levels in various biological matrices in children with ASD compared to neurotypical controls.
• To investigate potential disparities in Hg levels between gender- and age-matched ASD cases and controls across five clinical matrices: hair, whole blood, plasma, red blood cells (RBCs), and urine.

Main Methods:

• A systematic review and meta-analysis of 60 peer-reviewed case-control studies.
• Inclusion criteria focused on studies comparing Hg levels in hair, whole blood, plasma, RBCs, and urine between children with ASD and neurotypical controls.
• Studies involving children who received chelation therapy were excluded.

Main Results:

• No statistically significant differences in Hg levels were found in hair and urine between ASD cases and controls.
• Significantly higher Hg levels were observed in whole blood, plasma, and RBCs of children with ASD compared to controls.
• These findings suggest potential differences in Hg detoxification and excretion mechanisms in children with ASD.

Conclusions:

• Children with ASD may have reduced capacity to detoxify and excrete Hg, particularly indicated by higher levels in blood and RBCs.
• The findings underscore the potential detrimental role of Hg in ASD pathogenesis and highlight the importance of monitoring Hg levels in early childhood.
• There is a critical need for global initiatives to minimize Hg exposure due to its impact on neurodevelopmental health.