Adjuvant Effects of Vitamin A and Vitamin D Supplementation on Treatment of Children With ADHD

Procedures The patients showed deficiency or insufficiency in vitamin A (≤1.05 umol/ L) and vitamin D (≤50 nmol/L) are stratified by gender and randomly assigned in double-blind fashion in a 1:1:1 ratio to the vitamin AD supplementation group, vitamin D supplementation group or the placebo group. The participants will be given the related interventions. Placebo constituents by oily liquids without vitamin A and vitamin D. Placebo, vitamin AD and vitamin D are identical in the appearance to guarantee blind. These patients will be followed up at weeks 4 and 8 to evaluate the changes of ADHD symptoms after adding the adjunctive therapy to methylphenidate. And serum concentration of retinol and 25(OH)D are measured at weeks 8. Accordingly, the placebo group and vitamin D group will be prescribed with vitamin A and vitamin D supplementation on the grounds of retinol and 25 (OH)D concentration after the study.

Demographic questionnaire and clinical data The demographic questionnaire is completed by the child's primary caregiver, detailing child's name, gender, date of birth, height, weight, blood pressure, heart rate ; supplementation of vitamin A/D products or vitamin A/D-containing products. Clinical data will be ascertained from the medical records, including information about DSM-5 diagnosis, disease classification, current treatment, and comorbid conditions.

Sample size This study is a randomized double-blind controlled trial. Intervention groups are vitamin AD group and vitamin D group, control group is placebo group. The primary outcome index is changes in ADHD symptoms evaluated by Vanderbilt Assessment Scales and Questionnaire - Children with Difficulties (QCD) in the last 4 weeks or 8 weeks. The second outcome is the serum concentration of vitamin A and vitamin D. Conner's Parent Rating Scale (CPRS) was considered as the main outcome in the previous literature, the mean ± SD of ADHD index was 55.84 ± 10.2, 56.79 ± 9.6 for vitamin D + methylphenidate(n = 25), placebo + methylphenidate (n = 29) respectively. The investigators cautiously presume that the mean ± SD for vitamin AD + methylphenidate is 54 ± 9.88. Considering 0.05 of the alpha and 0.80 of power, a sample of 453 subjects divided among 3 groups are calculated by PASS 2020. And 504 subjects are enrolled in the study based on the dropout rate of 10%.

Statistical analysis All the data are analyzed using SPSS 19.0. The normality of variables are assessed by Kolmogorov Smirnov test. Comparison of parametric and nonparametric variables between groups are examined by F test and Kruskal-Wallis test, respectively. Paired t-test and Wilcoxon signed-rank test are used to investigate within-group differences. Confounding factors are adjusted by the analysis of covariance.

Bias control the investigators will describe both responders and non-responders on demographic questionnaire and clinical data in detail to assess the selection bias. And in order to decrease the dropout rate, the investigators will contact with the patient's parents about compliance to therapy by Wechat, E-mail, sometimes telephone contact is necessary.

Ethical matters and data protection The patients participated in the study will sign the informed consent (obtained from the guardian). And this study was approved by the local ethics committee . Patient's name will be abbreviated and the research data will be assigned a code then to provide to the researcher. The authorization from parents on the patient's health information remains valid until the study is completed. After that, researchers will delete private information from the study record.