Janssen 2010.

Study characteristics
Methods	Double‐blind 6‐month randomised controlled trial Outcome assessors blinded 59 of 70 completed
Participants	Outpatient clinic of the Department of Geriatric Medicine at the University Medical Centre, Utrecht, The Netherlands 70 women, mean age 81 years Inclusion criteria: women, > 65 years of age, able to walk and follow simple instructions, serum 25(OH)D concentration between 20 nmol/L and 50 nmol/L Exclusion criteria: treatment with vitamin D or steroids in the previous 6 months, history of hypercalcemia or renal stones, liver cirrhosis, serum creatinine > 200 μmol/L, malabsorptive bowel syndrome, primary hyperparathyroidism, uncontrolled thyroid disease, anticonvulsant drug therapy, and/or presence of any other condition that would probably interfere with the patient’s compliance (i.e. surgery planned)
Interventions	1. Vitamin D3 400 IU/d and 500 mg calcium/day 2. Placebo and calcium 500 mg/day Duration of treatment 6 months 28 out of 36, and 31 out of 34 completed
Outcomes	Measured at 6 months 1. Number of persons sustaining new non‐vertebral fracture 2. Number of persons sustaining new hip fracture 3. Number of persons dying 4. Number of persons with gastrointestinal adverse events
Notes	Hennie Janssen provided details of allocation of patient with hip fracture 15 January 2013, details of allocation for patients with gastrointestinal symptoms and patient who died 9 February 2013
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	States "randomly assigned"; no other information provided
Allocation concealment (selection bias)	Low risk	States "Trial medication was provided by an independent hospital pharmacist who also performed the randomization. . . No person involved, i.e. subjects, investigators, or physicians who treated the subjects, had access to the randomization procedure."