Correlation Study of Serum Vitamin D with Attention Deficit Hyperactivity Disorder in Children in China

Abstract

Background: To investigate serum vitamin D levels in children with attention deficit hyperactivity disorder (ADHD) , and to evaluate the associations of serum vitamin D levels with symptom severity, clinical subtypes and comorbid tic disorder (TD) of ADHD. Methods: Serum vitamin D (VD) levels and trace element contents were measured in 264 children with ADHD and 234 healthy children undergoing physical examination. The associations of VD levels with symptom severity, clinical subtypes and comorbid TD were analyzed. All statistical analyses were performed using SPSS 27.0 software. Results: 1. Serum VD level and contents of zinc, iron, calcium and magnesium among trace elements in the case group were all lower than those in the control group, and the differences were statistically significant (all P<0.05) . Serum VD level of ADHD children with onset in autumn and winter was lower than that of those with onset in spring and summer (P=0.008). 2. Serum VD levels in children with moderate and severe ADHD were significantly lower than those in the mild ADHD group and the control group (all P<0.01) . 3. Among all clinical subtypes, children with combined type (CT) ADHD had the lowest serum VD level, which was significantly lower than that of the control group (P<0.001) . 4. Serum VD level in the ADHD comorbid TD group was significantly lower than that in the pure ADHD group (P<0.001) . 5. Serum VD level in ADHD children was negatively correlated with symptom severity (r=-0.516; P<0.001) , clinical subtype (r=-0.431; P<0.01) , comorbid TD (r=-0.373; P<0.001) , inattention score on the SNAP-IV scale (r=-0.229; P=0.008) , oppositional defiant score (r=-0.189; P=0.03) and total SNAP-IV score (r=-0.218; P=0.012) , and was positively correlated with serum calcium level (r=0.502; P<0.001) . Conclusion: Children with ADHD have serum VD deficiency, as well as significantly reduced levels of zinc, iron, calcium and magnesium. Serum VD level is negatively correlated with symptom severity, clinical subtype, comorbid TD, inattention score, oppositional defiant score and total score on the SNAP-IV scale, and positively correlated with serum calcium level in children with ADHD.