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

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    Chen Li
Updated on 12 April 2021


Around 7.2% of children around the world are suffering from ADHD. On account of current medical treatment, a high remission rate can be reached for ADHD. Nevertheless, patients have to face a number of side effects associated with the treatment. It was informed that patients of ADHD have a tendency to vitamin A and vitamin D deficiency. The aim of the study is to determine the effect of vitamin A and vitamin D supplementation as adjunctive therapy to methylphenidate on symptoms of ADHD. 504 subjects aged 6-12 years with a diagnosis of ADHD based on DSM-5 criteria are randomly assigned into three groups to receive vitamin A 6000 IU/day and vitamin D 2100 IU/day, or vitamin D 2100 IU/day or placebo adding to methylphenidate for 8 weeks. Symptoms severity is assessed by Vanderbilt Assessment Scales and Questionnaire - Children with Difficulties at weeks 0, 4, and 8. Serum levels of retinol and 25(OH)D are measured at baseline and after 8 weeks. All the other sociodemographic data are assessed. The study can give more references on the application of vitamin A and vitamin D in addition to methylphenidate to ADHD. Future research is needed to clarify mechanism of vitamin A and vitamin D on ADHD.


  1. 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.
  2. 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.
  3. 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%.
  4. 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.
  5. 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.
  6. 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.

Condition Attention deficit hyperactivity disorder, Attention Deficit/Hyperactivity Disorder (ADHD - Pediatric), Attention Deficit/Hyperactivity Disorder (ADHD - Adults), Family Medicine-ADHD Pediatrics, Attention Deficit/Hyperactivity Disorder (ADHD - Adults), Attention Deficit/Hyperactivity Disorder (ADHD - Pediatric), Family Medicine-ADHD Pediatrics, adhd
Treatment placebos, Vitamin D, vitamin AD
Clinical Study IdentifierNCT04284059
SponsorChen Li
Last Modified on12 April 2021


Yes No Not Sure

Inclusion Criteria

Diagnose of ADHD according to DSM-5
Aged 6-12 years
Intelligence quotient (IQ) 70
Receiving methylphenidate (trade name Concerta) 18-54 mg/day once a day (began with 18 mg/day for a week and titrated gradually to the optimum dose not more than 54 mg/day)

Exclusion Criteria

Inconsistent or changing dose of methylphenidate during the participation period
Use of anticonvulsant drugs or hydrocortisone
Suffering from other neurological disorders and mental diseases now or in the past, such as convulsions, anxiety and depression
Suffer from metabolic disorders such as cholestasis, liver dysfunction, pancreatic insufficiency, measles, diarrhea, respiratory illness, severe inflammation or malnutrition, etc
Use of vitamins and vitamin-containing products
The serum concentration of vitamin A >1.05 umol/L and/ or vitamin D >50 nmol/L
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