Vitamin D supplementation for treatment of seasonal affective symptoms in healthcare professionals: a double-blind randomised placebo-controlled trial
Frandsen TB, Pareek M, Hansen JP, Nielsen CT
Published in BMC Research Notes
Methodology
Randomised, single-centre, double-blind, placebo-controlled trial (NCT01462058) in hospital healthcare professionals scoring 8 or more on question 2 of the Seasonal Pattern Assessment Questionnaire; 70 micrograms vitamin D daily or placebo for 3 months; primary outcome the self-reported SIGH-SAD.
Key Findings
Healthcare professionals with seasonal affective symptoms were randomised to 70 micrograms of vitamin D daily or placebo for 3 months; of 3345 invited and 50 screened, only 34 completed. There was no significant between-group difference in the primary depression measure (SIGH-SAD) at 12 weeks (p = 0.7, 95% CI -3.27 to 4.81). Well-being (WHO-5), weight, waist circumference, blood pressure, absenteeism and 25-hydroxyvitamin D also showed no significant differences. Symptoms improved significantly over time in both groups as winter turned to spring, consistent with natural seasonal recovery.
Conclusions
There were no significant between-group differences in the primary (SIGH-SAD) and secondary (WHO-5) as well as the exploratory outcome measures. Thus, the study failed to demonstrate an effect of vitamin D on SAD symptoms, but our findings may be limited by confounders.
Limitations
Only 34 of 50 screened participants completed, leaving the trial clearly underpowered; participants were not selected for low vitamin D status, so the question of whether supplementation helps deficient people remains open.
Supplements Studied
There were no significant between-group differences in the primary (SIGH-SAD) and secondary (WHO-5) as well as the exploratory outcome measures. Thus, the study failed to demonstrate an effect of vitamin D on SAD symptoms, but our findings may be limited by confounders.
Related Health Concerns
Study Details
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.