Wepner 2014.

Methods	Randomised, double‐blind, placebo‐controlled study. Duration: 25 weeks of treatment, follow‐up examination at week 49
Participants	Participants (N = 42) with fibromyalgia and serum calcifediol levels < 32 ng/L; 30 completers (90% women): mean (± SD) age 48.4 ± 5.3 years, range 35‐55 years
Interventions	Cholecalciferol (in triglyceride solution) 1200 or 2400 IU daily, depending on vitamin D level Placebo: triglyceride solution
Outcomes	Visual analogue pain scale, Short Form (36) Health Survey (SF‐36), Fibromyalgia Impact Questionnaire, all‐cause withdrawals, and baseline and end‐of‐trial 25‐hydroxyvitamin D levels
Notes	Oxford Quality Score: R2, D2, W1 = 5/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random number generator
Allocation concealment (selection bias)	Low risk	Random allocation done by statistician who was not involved in testing or treatment
Blinding (performance bias and detection bias) All outcomes	Low risk	Cholecalciferol in triglyceride solution as active, triglyceride solution alone as placebo. Mock dose changes in placebo group
Incomplete outcome data (attrition bias) All outcomes	High risk	12/42 participants dropped out, completer analysis
Size	High risk	< 50 participants in each treatment arm