Effect of vitamin D supplement on depression scores in people with low levels of serum 25-hydroxyvitamin D: nested case–control study and randomised clinical trial
Marie Kjærgaard, Knut Waterloo, Catharina E. A. Wang, Bjørg Almås, Yngve Figenschau, Moira S. Hutchinson, Johan Svartberg, Rolf Jorde
  • Declaration of interest




To compare depressive symptoms in participants with low and high serum 25-hydroxyvitamin D (25(OH)D) levels and to examine whether supplementation with vitamin D3 would improve symptoms in those with low serum 25(OH)D levels.


Participants with low 25(OH)D levels were randomised to either placebo or 40 000 IU vitamin D3 per week for 6 months. Individuals with high serum 25(OH)D levels were used as nested controls. Depressive symptoms were evaluated with the Beck Depression Inventory, Hospital Anxiety and Depression Scale, Seasonal Pattern Assessment Scale and Montgomery–Åsberg Depression Rating Scale. The study was registered at ClinicalTrials.gov (NCT00960232).


Participants with low 25(OH)D levels (n = 230) at baseline were more depressed (P<0.05) than participants with high 25(OH)D levels (n = 114). In the intervention study no significant effect of high-dose vitamin D was found on depressive symptom scores when compared with placebo.


Low levels of serum 25(OH)D are associated with depressive symptoms, but no effect was found with vitamin D supplementation.