Valentina Crisafi

This is an exploratory case–control study assessed levels of metals and essential trace elements in hair samples from children with Autism Spectrum Disorder (ASD) and neurotypical controls, exploring potential differences according to sex. A total of 154 children (61 children with ASD and 93 controls) aged 4–18 years were enrolled at the same clinical site in Eastern Sicily. Demographic, perinatal, dietary, and exposure information was collected through structured parental questionnaires. Hair samples were analyzed using inductively coupled plasma mass spectrometry. Children with ASD showed distinct elemental patterns. Females with ASD had higher median nickel (0.25 vs.0.20 µg/g), lead (1.11 vs.0.55 µg/g), chromium (0.87 vs.0.49 µg/g), and aluminum (10.27 vs. 6.97 µg/g) compared with female controls; similar but smaller differences appeared in males. Mercury levels were consistently lower in children with ASD for both sexes (females: 0.25 vs.0.60 µg/g; males: 0.30 vs.0.58 µg/g). Essential trace elements were markedly elevated in children with ASD: zinc reached 132 µg/g in ASD females vs. 83 µg/g in controls, and 129 vs. 65 µg/g in males; selenium and copper were also higher across sexes. Maternal and child characteristics differed between groups. Mothers of children with ASD reported more infections (30.9% vs. 9.6%) and therapies during pregnancy (43.9% vs.22.6%), while children with ASD showed more gastric disorders (40.4%vs.9.4%), specific diets (21.1% vs.3.5%), and vitamin use (26.3% vs.3.5%). Findings suggest sex-related differences in hair metals and trace elements profiles among children with ASD. The low mercury levels observed in children with ASD showld be interpreted with caution, given that factors such as dietary habits, supplement intake, or differences in metal metabolism were not directly assessed in this study.