Abstract / Summary
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder. Evidence linking peripheral iron stores and zinc status to ADHD is heterogeneous, and Iraqi paediatric data are limited. An ambispective case-control study was conducted in Al-Najaf City, Iraq, from January 2025 to April 2026. Sixty-six treatment-naive children aged 5–14 years with psychiatrist-confirmed DSM-5 ADHD were compared with 110 clinically assessed controls. Parent and teacher Vanderbilt scales were available for all children with ADHD. Morning fasting serum ferritin and zinc were measured before treatment. Age- and sex-adjusted associations were examined using biomarker-specific Firth logistic regression. Median ferritin level was lower in children with ADHD than controls (7.71 [IQR 7.34–15.22] vs. 30.52 [23.38–37.66] µg/L; P < 0.001), as was the median zinc level (49.93 [49.52–65.69] vs. 86.06 [74.79–97.34] µg/dL; P < 0.001). Ferritin < 15 µg/L occurred in 62.1% of children with ADHD and 0% of controls; using the zinc-kit reference interval, zinc < 70 µg/dL occurred in 100.0% and 14.5%, respectively (both P < 0.001). Ferritin and zinc were strongly correlated within the ADHD group (Spearman ρ = 0.861; P < 0.001). Higher concentrations of each biomarker were associated with lower odds of ADHD status after adjustment for age and sex. Children with ADHD in this Iraqi sample had lower serum ferritin and zinc concentrations than clinically assessed controls. These findings show association, not causation or therapeutic benefit; subgroup findings remain exploratory.