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

ADHD Clinical Trial

Official title:

Adjuvant Effects of Vitamin A and Vitamin D Supplementation on Treatment of Children With ADHD:A Randomized, Double Blind, Placebo-controlled, Multicentric Trial.

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT04284059
• Other study ID #: CHENLI
• Status: Recruiting
• Phase: Phase 4
• Start date: February 25, 2021
• Est. completion date: August 30, 2022

Study information

• Verified date: April 2021
• Source: Children's Hospital of Chongqing Medical University
• Contact: Li Chen, doctor
• Phone: 136 7762 0103
• Email: chenli2012[@]126.com
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Description:

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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 504
• Est. completion date: August 30, 2022
• Est. primary completion date: May 30, 2022
• Accepts healthy volunteers: No
• Gender: All
• Age group: 6 Years to 12 Years

Eligibility

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

• IQ=70

• The serum concentration of vitamin A >1.05 umol/L and/ or vitamin D >50 nmol/L

Related Conditions & MeSH terms

• ADHD

Intervention

Drug:
• Placebos
Placebo, vitamin AD and vitamin D are identical in the appearance to guarantee blind. The patients need to administrate 3 capsules once a day for 8 weeks.

Dietary Supplement:
• vitamin AD
A vitamin AD capsule contains vitamin A 2000 IU and vitamin D 700 IU. The patients need to administrate 3 capsules once a day for 8 weeks.
• vitamin D
A vitamin D capsule contains vitamin D 400 IU. The patients need to asministrate 6 capsules/time, once a day for 2 weeks, then change to 5 capsules/time, once a day for 6 weeks.

Locations

Country	Name	City	State
China	the First Hospital of Jilin University	Chang chun	Jilin
China	Growth, Development and Mental health of Children and Adolescence Center	Chongqing	Chongqing
China	Qilu Hospital of Shandong University	Jinan	Shandonng

Sponsors (1)

Lead Sponsor	Collaborator
Chen Li

Country where clinical trial is conducted

China, 

References & Publications (22)

Biederman J, Faraone SV. Attention-deficit hyperactivity disorder. Lancet. 2005 Jul 16-22;366(9481):237-48. Review. Erratum in: Lancet. 2006 Jan 21;367(9506):210. — View Citation

Dehbokri N, Noorazar G, Ghaffari A, Mehdizadeh G, Sarbakhsh P, Ghaffary S. Effect of vitamin D treatment in children with attention-deficit hyperactivity disorder. World J Pediatr. 2019 Feb;15(1):78-84. doi: 10.1007/s12519-018-0209-8. Epub 2018 Nov 19. — View Citation

Duric NS, Assmus J, Gundersen D, Duric Golos A, Elgen IB. Multimodal treatment in children and adolescents with attention-deficit/hyperactivity disorder: a 6-month follow-up. Nord J Psychiatry. 2017 Jul;71(5):386-394. doi: 10.1080/08039488.2017.1305446. Epub 2017 Mar 27. — View Citation

Elshorbagy HH, Barseem NF, Abdelghani WE, Suliman HAI, Al-Shokary AH, Abdulsamea SE, Elsadek AE, Abdel Maksoud YH, Nour El Din DMAE. Impact of Vitamin D Supplementation on Attention-Deficit Hyperactivity Disorder in Children. Ann Pharmacother. 2018 Jul;52(7):623-631. doi: 10.1177/1060028018759471. Epub 2018 Feb 18. — View Citation

Evans E, Piccio L, Cross AH. Use of Vitamins and Dietary Supplements by Patients With Multiple Sclerosis: A Review. JAMA Neurol. 2018 Aug 1;75(8):1013-1021. doi: 10.1001/jamaneurol.2018.0611. Review. Erratum in: JAMA Neurol. 2018 Aug 1;75(8):1028. — View Citation

Faraone SV. The pharmacology of amphetamine and methylphenidate: Relevance to the neurobiology of attention-deficit/hyperactivity disorder and other psychiatric comorbidities. Neurosci Biobehav Rev. 2018 Apr;87:255-270. doi: 10.1016/j.neubiorev.2018.02.001. Epub 2018 Feb 8. Review. — View Citation

Fasihpour B, Moayeri H, Shariat M, Keihanidoust Z, Effatpanah M, Khedmat L. Vitamin D deficiency in school-age Iranian children with attention-deficit/hyperactivity disorder (ADHD) symptoms: A critical comparison with healthy controls. Child Neuropsychol. 2020 May;26(4):460-474. doi: 10.1080/09297049.2019.1665638. Epub 2019 Sep 13. — View Citation

Fragoso YD, Stoney PN, McCaffery PJ. The evidence for a beneficial role of vitamin A in multiple sclerosis. CNS Drugs. 2014 Apr;28(4):291-9. doi: 10.1007/s40263-014-0148-4. Review. — View Citation

Gallo EF, Posner J. Moving towards causality in attention-deficit hyperactivity disorder: overview of neural and genetic mechanisms. Lancet Psychiatry. 2016 Jun;3(6):555-67. doi: 10.1016/S2215-0366(16)00096-1. Epub 2016 May 13. Review. — View Citation

Hinshaw SP. Attention Deficit Hyperactivity Disorder (ADHD): Controversy, Developmental Mechanisms, and Multiple Levels of Analysis. Annu Rev Clin Psychol. 2018 May 7;14:291-316. doi: 10.1146/annurev-clinpsy-050817-084917. Epub 2017 Dec 8. Review. — View Citation

Lopes FM, da Motta LL, De Bastiani MA, Pfaffenseller B, Aguiar BW, de Souza LF, Zanatta G, Vargas DM, Schönhofen P, Londero GF, de Medeiros LM, Freire VN, Dafre AL, Castro MA, Parsons RB, Klamt F. RA Differentiation Enhances Dopaminergic Features, Changes Redox Parameters, and Increases Dopamine Transporter Dependency in 6-Hydroxydopamine-Induced Neurotoxicity in SH-SY5Y Cells. Neurotox Res. 2017 May;31(4):545-559. doi: 10.1007/s12640-016-9699-0. Epub 2017 Feb 2. — View Citation

McCaffery P, Dräger UC. High levels of a retinoic acid-generating dehydrogenase in the meso-telencephalic dopamine system. Proc Natl Acad Sci U S A. 1994 Aug 2;91(16):7772-6. — View Citation

Mohammadpour N, Jazayeri S, Tehrani-Doost M, Djalali M, Hosseini M, Effatpanah M, Davari-Ashtiani R, Karami E. Effect of vitamin D supplementation as adjunctive therapy to methylphenidate on ADHD symptoms: A randomized, double blind, placebo-controlled trial. Nutr Neurosci. 2018 Apr;21(3):202-209. doi: 10.1080/1028415X.2016.1262097. Epub 2016 Dec 7. — View Citation

Moretti R, Morelli ME, Caruso P. Vitamin D in Neurological Diseases: A Rationale for a Pathogenic Impact. Int J Mol Sci. 2018 Jul 31;19(8). pii: E2245. doi: 10.3390/ijms19082245. Review. — View Citation

Ono K, Yamada M. Vitamin A and Alzheimer's disease. Geriatr Gerontol Int. 2012 Apr;12(2):180-8. doi: 10.1111/j.1447-0594.2011.00786.x. Epub 2011 Dec 23. Review. — View Citation

Palacios C, Gonzalez L. Is vitamin D deficiency a major global public health problem? J Steroid Biochem Mol Biol. 2014 Oct;144 Pt A:138-45. doi: 10.1016/j.jsbmb.2013.11.003. Epub 2013 Nov 12. Review. — View Citation

Pertile RA, Cui X, Eyles DW. Vitamin D signaling and the differentiation of developing dopamine systems. Neuroscience. 2016 Oct 1;333:193-203. doi: 10.1016/j.neuroscience.2016.07.020. Epub 2016 Jul 20. — View Citation

Pertile RAN, Cui X, Hammond L, Eyles DW. Vitamin D regulation of GDNF/Ret signaling in dopaminergic neurons. FASEB J. 2018 Feb;32(2):819-828. doi: 10.1096/fj.201700713R. Epub 2018 Jan 4. — View Citation

Russell VA. Overview of animal models of attention deficit hyperactivity disorder (ADHD). Curr Protoc Neurosci. 2011 Jan;Chapter 9:Unit9.35. doi: 10.1002/0471142301.ns0935s54. Review. — View Citation

Seyedi M, Gholami F, Samadi M, Djalali M, Effatpanah M, Yekaninejad MS, Hashemi R, Abdolahi M, Chamari M, Honarvar NM. The Effect of Vitamin D3 Supplementation on Serum BDNF, Dopamine, and Serotonin in Children with Attention-Deficit/Hyperactivity Disorder. CNS Neurol Disord Drug Targets. 2019;18(6):496-501. doi: 10.2174/1871527318666190703103709. — View Citation

Song P, Wang J, Wei W, Chang X, Wang M, An L. The Prevalence of Vitamin A Deficiency in Chinese Children: A Systematic Review and Bayesian Meta-Analysis. Nutrients. 2017 Nov 25;9(12). pii: E1285. doi: 10.3390/nu9121285. Review. — View Citation

Wolraich ML, Hagan JF Jr, Allan C, Chan E, Davison D, Earls M, Evans SW, Flinn SK, Froehlich T, Frost J, Holbrook JR, Lehmann CU, Lessin HR, Okechukwu K, Pierce KL, Winner JD, Zurhellen W; SUBCOMMITTEE ON CHILDREN AND ADOLESCENTS WITH ATTENTION-DEFICIT/HYPERACTIVE DISORDER. Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents. Pediatrics. 2019 Oct;144(4). pii: e20192528. doi: 10.1542/peds.2019-2528. Erratum in: Pediatrics. 2020 Mar;145(3):. — View Citation

* Note: There are 22 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	The changes in ADHD clinical symptoms-Predominantly Inattentive subtype estimated by Chinese version of Vanderbilt parent assessment scale	The Vanderbilt parent assessment scale is designed to measure the severity of ADHD symptoms for children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 49-56 are performance measures. The symptom measures in the scale, scored 0 to 3. A positive response in symptom assessment part is a 2 or 3 (often, very often). The performance measures in the scale, scored 1 to 5, with 4 and 5 being somewhat of a problem/problematic.; The scoring standard for Predominantly Inattentive subtype: Must score a 2 or 3 on 6 out of 9 items on questions 1-9 AND Score a 4 or 5 on any of the Performance questions 49-56. The higher scores mean a worse outcome.	at baseline
Primary	The changes in ADHD clinical symptoms-Predominantly Inattentive subtype estimated by Chinese version of Vanderbilt teacher assessment scale	The Vanderbilt teacher assessment scale is designed to measure the severity of ADHD symptoms for children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 36-43 are performance measures. The symptom measures in the scale, scored 0 to 3. A positive response in symptom assessment part is a 2 or 3 (often, very often). The performance measures in the scale, scored 1 to 5, with 4 and 5 being somewhat of a problem/problematic.; The scoring standard for Predominantly Inattentive subtype: Must score a 2 or 3 on 6 out of 9 items on questions 1-9 AND Score a 4 or 5 on any of the Performance questions 36-43. The higher scores mean a worse outcome.	at baseline
Primary	The changes in ADHD clinical symptoms-Predominantly Hyperactive/Impulsive subtype estimated by Chinese version of Vanderbilt parent assessment scale	The Vanderbilt parent assessment scale is designed to measure the severity of ADHD symptoms for children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 49-56 are performance measures. The symptom measures in the scale, scored 0 to 3. A positive response in symptom assessment part is a 2 or 3 (often, very often). The performance measures in the scale, scored 1 to 5, with 4 and 5 being somewhat of a problem/problematic.; The scoring standard for Predominantly Hyperactive/Impulsive subtype: Must score a 2 or 3 on 6 out of 9 items on questions 10-18 AND Score a 4 or 5 on any of the Performance questions 49-56. The higher scores mean a worse outcome.	at baseline
Primary	The changes in ADHD clinical symptoms-Predominantly Hyperactive/Impulsive subtype estimated by Chinese version of Vanderbilt teacher assessment scale	The Vanderbilt teacher assessment scale is designed to measure the severity of ADHD symptoms for children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 36-43 are performance measures. The symptom measures in the scale, scored 0 to 3. A positive response in symptom assessment part is a 2 or 3 (often, very often). The performance measures in the scale, scored 1 to 5, with 4 and 5 being somewhat of a problem/problematic.; The scoring standard for Predominantly Hyperactive/Impulsive subtype: Must score a 2 or 3 on 6 out of 9 items on questions 10-18 AND Score a 4 or 5 on any of the Performance questions 36-43. The higher scores mean a worse outcome.	at baseline
Primary	The changes in ADHD clinical symptoms-ADHD Combined Inattention/Hyperactivity estimated by Chinese version of Vanderbilt parent assessment scale	The Vanderbilt parent assessment scale is designed to measure the severity of ADHD symptoms for children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 49-56 are performance measures. The symptom measures in the scale, scored 0 to 3. A positive response in symptom assessment part is a 2 or 3 (often, very often). The performance measures in the scale, scored 1 to 5, with 4 and 5 being somewhat of a problem/problematic.; The scoring standard for ADHD Combined Inattention/Hyperactivity: Must score a 2 or 3 on 6 out of 9 items not only on questions 1-9 but also on questions 10-18. AND Score a 4 or 5 on any of the Performance questions 49-56. The higher scores mean a worse outcome.	at baseline
Primary	The changes in ADHD clinical symptoms-ADHD Combined Inattention/Hyperactivity estimated by Chinese version of Vanderbilt teacher assessment scale	The Vanderbilt teacher assessment scale is designed to measure the severity of ADHD symptoms for children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 36-43 are performance measures. The symptom measures in the scale, scored 0 to 3. A positive response in symptom assessment part is a 2 or 3 (often, very often). The performance measures in the scale, scored 1 to 5, with 4 and 5 being somewhat of a problem/problematic.; The scoring standard for ADHD Combined Inattention/Hyperactivity: Must score a 2 or 3 on 6 out of 9 items not only on questions 1-9 but also on questions 10-18. AND Score a 4 or 5 on any of the Performance questions 36-43. The higher scores mean a worse outcome.	at baseline
Primary	The changes in ADHD clinical symptoms-Predominantly Inattentive subtype estimated by Chinese version of Vanderbilt parent follow-up assessment	The Vanderbilt parent follow-up assessment is designed to track treatment effect over time for ADHD children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 19-26 are performance measures. The symptom measures in the scale, scored 0 to 3 (Never, Occasionally, Often, Very Often). The performance measures in the scale, scored 1 to 5 (Excellent, Above Average, Average, Somewhat of a Problem, Performance Problematic).; The scoring standard for Predominantly Inattentive subtype: 1) Calculate Total Symptom Score for questions 1-18. 2) Calculate Average Performance Score for questions 19-26. The higher scores mean a worse outcome.	at weeks 4 and 8
Primary	The changes in ADHD clinical symptoms-Predominantly Inattentive subtype estimated by Chinese version of Vanderbilt teacher follow-up assessment	The Vanderbilt teacher follow-up assessment is designed to track treatment effect over time for ADHD children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 19-26 are performance measures. The symptom measures in the scale, scored 0 to 3 (Never, Occasionally, Often, Very Often). The performance measures in the scale, scored 1 to 5 (Excellent, Above Average, Average, Somewhat of a Problem, Performance Problematic).; The scoring standard for Predominantly Inattentive subtype: 1) Calculate Total Symptom Score for questions 1-18. 2) Calculate Average Performance Score for questions 19-26. The higher scores mean a worse outcome.	at weeks 4 and 8
Primary	The changes in ADHD clinical symptoms-Predominantly Hyperactive/Impulsive subtype estimated by Chinese version of Vanderbilt parent follow-up assessment	The Vanderbilt parent follow-up assessment is designed to track treatment effect over time for ADHD children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 19-26 are performance measures. The symptom measures in the scale, scored 0 to 3 (Never, Occasionally, Often, Very Often). The performance measures in the scale, scored 1 to 5 (Excellent, Above Average, Average, Somewhat of a Problem, Performance Problematic).; The scoring standard for Predominantly Hyperactive/Impulsive subtype: 1) Calculate Total Symptom Score for questions 1-18. 2) Calculate Average Performance Score for questions 19-26. The higher scores mean a worse outcome.	at weeks 4 and 8
Primary	The changes in ADHD clinical symptoms-Predominantly Hyperactive/Impulsive subtype estimated by Chinese version of Vanderbilt teacher follow-up assessment	The Vanderbilt teacher follow-up assessment is designed to track treatment effect over time for ADHD children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 19-26 are performance measures. The symptom measures in the scale, scored 0 to 3 (Never, Occasionally, Often, Very Often). The performance measures in the scale, scored 1 to 5 (Excellent, Above Average, Average, Somewhat of a Problem, Performance Problematic).; The scoring standard for Predominantly Hyperactive/Impulsive subtype: 1) Calculate Total Symptom Score for questions 1-18. 2) Calculate Average Performance Score for questions 19-26. The higher scores mean a worse outcome.	at weeks 4 and 8
Primary	The changes in ADHD clinical symptoms-ADHD Combined Inattention/Hyperactivity estimated by Chinese version of Vanderbilt parent follow-up assessment	The Vanderbilt parent follow-up assessment is designed to track treatment effect over time for ADHD children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 19-26 are performance measures. The symptom measures in the scale, scored 0 to 3 (Never, Occasionally, Often, Very Often). The performance measures in the scale, scored 1 to 5 (Excellent, Above Average, Average, Somewhat of a Problem, Performance Problematic).; The scoring standard for ADHD Combined Inattention/Hyperactivity: 1) Calculate Total Symptom Score for questions 1-18. 2) Calculate Average Performance Score for questions 19-26. The higher scores mean a worse outcome.	at weeks 4 and 8
Primary	The changes in ADHD clinical symptoms-ADHD Combined Inattention/Hyperactivity estimated by Chinese version of Vanderbilt teacher follow-up assessment	The Vanderbilt teacher follow-up assessment is designed to track treatment effect over time for ADHD children aged 6 to 12. It has 2 components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms relevant to inattentive (items 1-9) and hyperactive (items 10-18) ADHD. The items 19-26 are performance measures. The symptom measures in the scale, scored 0 to 3 (Never, Occasionally, Often, Very Often). The performance measures in the scale, scored 1 to 5 (Excellent, Above Average, Average, Somewhat of a Problem, Performance Problematic).; The scoring standard for ADHD Combined Inattention/Hyperactivity: 1) Calculate Total Symptom Score for questions 1-18. 2) Calculate Average Performance Score for questions 19-26. The higher scores mean a worse outcome.	at weeks 4 and 8
Primary	The changes in ADHD clinical symptoms	The Questionnaire - Children with Difficulties (QCD) measures the daily-life problems in children aged 6-18 years during the special time of the day, including in the morning, during school, after school, in the evening, and overall difficulties over the entire day and night. It has been proved the Chinese version of QCD has good validity and reliability. Filled in by the parents, the scale consists of 20 questions with regard to ADHD-related difficulties. Each question is scored on a four-point scale: 0 = completely disagree, 1 = somewhat (partially) agree, 2 = mostly agree, and 3 = completely agree. Score of 30 - 35 is considered as cut-off value for functional impairment and score of less than 30 is considered as functional impairment (Full marks: 57). The lower scores indicate lower life functioning and more difficulty in children's daily activities.	at baseline, weeks 4 and 8
Secondary	Serum concentration of vitamin A.	Vitamin A state is measured by the serum concentration of retinol through high performance liquid chromatography (HPLC) from 2 milliliter of venous blood. The vitamin A status is categorized based on serum retinol: <0.35 µmol/L is considered very deficient, 0.35-0.7 µmol/L deficient, 0.7-1.05 µmol/L marginal, 1.05-2.56 µmol/L adequate, and >2.56 µmol/L toxic. Too low or too high concentrations are harmful	at baseline and weeks 8
Secondary	Serum concentration of vitamin D.	Vitamin D state is measured by the serum concentration of 25OHD through high performance liquid chromatography (HPLC) from 2 milliliter of venous blood. The values of serum vitamin D level are classified into 4 categories: <30 nmol/L is regarded as deficiency, 30-50 nmol/L insufficiency, 50-250 nmol/L normal, and >250 nmol/L toxic . Too low or too high concentrations are harmful?	at baseline and weeks 8