Flicker 2005.

Methods	Randomised, double‐blind, placebo‐controlled trial using parallel group design (two intervention groups).
Participants	Country: Australia. Number of participants randomised: 625, older residents (mean age 83.4), 95% females, with serum 25‐hydroxyvitamin D levels between 25 and 90 nmol/L. Inclusion criteria: older people resident in hostels and nursing homes with serum 25‐hydroxyvitamin D levels between 25 and 90 nmol/L. Exclusion criteria: use of agents that could affect bone and mineral metabolism, such as warfarin, chronic heparin therapy, vitamin D therapy within the previous three months, glucocorticoids at an average daily dose of greater than 5 mg prednisolone (or equivalent) for more than one month within the preceding year, current use of bisphosphonates, and hormone replacement therapy, thyrotoxicosis within the previous three years, primary hyperparathyroidism treated within the previous three years, multiple myeloma, Paget’s disease of bone, history of malabsorption, intercurrent active malignancy, and other disorders affecting bone and mineral metabolism.
Interventions	Participants were randomly assigned to receive: Intervention group: vitamin D3 (10000 IU) weekly until November 1998 and thereafter vitamin D31000 IU daily plus calcium (600 mg) daily (n = 313); Control group: calcium (600 mg) (n = 312); for a two‐year period.
Outcomes	The primary outcomes were falls and fractures.
Stated aim of study	"To test whether administration of vitamin D could reduce the incidence of falls and fractures in nursing home residents."
Notes	"Supplements and placebos were purchased commercially, and the suppliers played no role in the trial design or in the collection, analysis, or interpretation of data."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Sequence generation was achieved using computer random number generation.
Allocation concealment (selection bias)	Low risk	Allocation was controlled by a central and independent randomisation unit so that intervention allocations could not have been foreseen in advance of, or during, enrolment. An individual who was not involved in contact with the participants or the residential care institutions performed randomisation.
Blinding (performance bias and detection bias) All outcomes	Low risk	The trial was described as blinded, the parties that were blinded, and the method of blinding was described, so that knowledge of allocation was adequately prevented during the trial. "Participants were randomised to receive sequentially numbered bottles containing vitamin D or placebo. Both interventions had matching placebo preparations given in identical fashion, and residents, institutional staff, and trial staff were blinded to treatment allocation."
Incomplete outcome data (attrition bias) All outcomes	Low risk	The numbers and reasons for dropouts and withdrawals in all intervention groups were described.
Selective reporting (reporting bias)	Low risk	Pre‐defined, or clinically relevant and reasonably expected outcomes are reported on.
Industry bias	Low risk	The trial is not funded by a manufacturer of vitamin D.
Other bias	Low risk	The trial appears to be free of other components that could put it at risk of bias.