An Evaluation of the Effect of Vitamin D Supplementation on Depressive Symptoms Among Chinese Early Adolescents

Effect of Vitamin D Supplementation on Depressive Symptoms in Chinese Early Adolescents

The goal of this randomized controlled clinical trial is to investigate the effects of vitamin D3 supplementation on depression in Chinese early adolescents with elevated depressive symptoms and vitamin D deficiency. The main question it aims to answer whether vitamin D3 supplementation can reduce depressive symptoms.

Participants in the intervention group will receive vitamin D3 capsules and mental health education. The control group will receive vitamin D3 placebo and mental health education.

Researchers will compare the change in depressive symptoms from baseline to post-intervention at 12 weeks between the intervention and control groups.

Investigators will conduct a randomized controlled trial to examine whether vitamin D3 supplementation can improve depressive symptoms. Participants will be recruited from two middle schools. Participants will be randomly assigned into a supplementation or placebo group. Supplementation arm will receive oral dose 2000 IU vitamin D3 per day for 6 weeks and followed by 800 IU per day for 6 weeks; placebo arm will receive placebo every day for 12 weeks. Both of these two groups will receive additional mental health education. For the first 6 weeks, vitamin D or placebo will be administrated every two weeks. For the next 6 weeks, vitamin D or placebo will be administrated every three weeks. The primary outcome of this study is to compare the change of depressive symptoms between supplementation or placebo group from pre- to post-intervention at 12 weeks.

Inclusion Criteria:

1. 7th-9th students whose caregivers signed informed consents;
2. students with serum 25(OH)D concentrations below 20 ng/mL;
3. students with self-reported depressive symptoms (BDI-II score of 14 or higher)

Exclusion Criteria:

1. students who are currently receiving or have used anti-psychotic treatments or interventions (including drugs and non-drugs) in the past 3 months;
2. students who have serious health conditions (e.g., organic or functional brain diseases, major psychiatric disorders, cardiovascular diseases, serious infectious diseases, chronic gastrointestinal diseases, and hepatic or renal diseases);
3. students who are currently taking or have taken vitamin D supplements in the past 3 months;
4. students with self-reported serious suicidal ideation, suicidal plans and attempts in the past 3 months;
5. students with intellectual disability;
6. students who are allergic to vitamin D or soybean oil components.