Therapeutic effect of combined vitamin D and DHA supplementation on preschool children with attention deficit hyperactivity disorder

Objective·To investigate the therapeutic effect of combined vitamin D and docosahexaenoic acid (DHA) supplementation on preschool children with attention deficit hyperactivity disorder (ADHD).Methods·From April 2021 to May 2021, a total of 1 412 children aged 4 to 6 years from eight kindergartens in Pudong New Area of Shanghai, including Tangqiao Street, Chuansha Town, and Heqing Town, were randomly selected by stratified cluster random sampling method. Attention and hyperactivity symptom assessment was performed using the Conner′s Scale, Diagnosis and Statistical Manual of Mental Disorders(fifth edition, DSM-Ⅴ), and Swanson, Nolan, and Pelham (version Ⅳ, SNAP-Ⅳ) Scale, and other neurodevelopmental disorders were excluded using the Wechsler Intelligence Scale. A total of 82 preschool children with ADHD were enrolled, and after fully informing them of the intervention measures, they were divided into an intervention group (n=64) and a control group (n=18) based on their parents′ choice. The control group received routine health education. In addition to routine health education, the intervention group received daily supplementation of Vitamin D (800 IU) and DHA (400 mg). Venous blood samples were collected from both groups at baseline, 3 months, and 12 months for the measurement of serum 25 hydroxy vitamin D [25 (OH) D] and DHA levels. ADHD symptoms were evaluated using Conner′s Scale, SNAP-Ⅳ Scale, and DSM-Ⅴ.Results·After 3 and 12 months of intervention in the intervention group, serum 25 (OH) D levels and DHA levels were significantly higher (P<0.05), the ADHD symptom scores, including impulsivity-hyperactivity and hyperactivity index scores in Conner′s Scale, the attention and hyperactivity/impulsivity scores in SNAP-Ⅳ Scale, and the attention and hyperactivity/impulsivity scores in DSM-Ⅴ, were significantly reduced compared with the scores before the intervention (P<0.05). There was no significant difference in serum 25 (OH) D and DHA levels, or ADHD symptom scores, at the 3- and 12-month follow-ups compared to baseline. After 3 months of nutritional intervention in the intervention group, the hyperactivity/impulsivity scores in SNAP-Ⅳ Scale and DSM-Ⅴ were significantly improved compared to the control group (P<0.05). After 12 months of intervention, conduct problems, impulsive-hyperactivity and hyperactivity index scores in Conner′s Scale, and hyperactivity/ impulsivity scores in SNAP-Ⅳ Scale and DSM-Ⅴ showed significant improvement compared to the control group (P<0.05).Conclusion·Combined supplementation with vitamin D and DHA significantly improves serum 25 (OH) D and DHA levels and alleviates ADHD symptoms in preschool children.