A case–control study of heavy metals and melatonin levels in autistic children from Mizoram, Northeast India

Purpose Autism spectrum disorder (ASD) is a neurodevelopmental condition influenced by genetic and environmental factors. This study aims to investigate heavy metal concentrations and melatonin levels in autistic children compared to neurotypical children in Mizoram, a tribal region of Northeast India with unique environmental exposures. Design/methodology/approach First-morning urine and timed (09:00–10:00 p.m.) saliva samples were collected from 38 autistic and 26 children (aged 3–13 years). Metal concentrations (iron, lead, aluminum, manganese, etc.) were quantified via microwave plasma-atomic emission spectroscopy and melatonin via enzyme-linked immunosorbent assay. Blinded analyses used Mann–Whitney U tests (metals) and independent t-tests (melatonin). Findings Autistic children had significantly higher urinary aluminum (1.80 µg/L, p = 0.041) and lower iron, lead and manganese (p < 0.05). Melatonin levels did not differ between autistic and neurotypical children (16.88 vs 22.18 ng/mL, p = 0.41). Research limitations/implications Small sample size and cross-sectional design limit the causal inferences of this study. Replication in larger cohorts is needed to ascertain the role of aluminum and the potential sources of environmental and dietary exposures and their temporal relationship with ASD features. Practical implications Results suggest monitoring aluminum exposure in autistic populations, particularly in regions with potential environmental contamination. To reduce aluminum exposure risks in autistic children, clinics could prioritize testing for those with sleep or gastrointestinal issues. Public awareness campaigns should promote safer cookware alternatives, like clay or stainless steel, and regulate processed food sources. In addition, addressing iron deficiency through fortified rice or supplements could help mitigate nutritional vulnerabilities. Social implications This research underscores the importance of environmental health policies in supporting the well-being of autistic individuals, especially in communities with elevated exposure risks. Originality/value To the best of the authors’ knowledge, this is the first study to document metal-level differences in autistic individuals from a unique ethnic Mizo tribal population providing actionable data for regional public health strategies.