Sanders 2010.

Methods	Single‐centre, randomised, double‐blind, placebo‐controlled trial using parallel group design (2 intervention groups); The Vital D study
Participants	Number of participants randomised: 2258 community‐dwelling women, 70 years or older (mean age 76 years) considered to be at high risk of fracture. Inclusion criteria: community‐dwelling women at higher risk of hip fracture, defined by criteria such as maternal hip fracture, past fracture, or self‐reported faller. Exclusion criteria: unable to provide informed consent or information about falls or fractures; permanently resident at a high‐level care facility; had an albumin‐corrected calcium level higher than 2.65 mmol/L; or had a creatinine level higher than 150 μmol/L, or currently took vitamin D doses of 400 IU or more, calcitriol, or antifracture therapy.
Interventions	Participants were randomly assigned to receive: Intervention group: vitamin D₃ 500,000 IU yearly (n = 1131) Comparator group: matched placebo tablet of vitamin D yearly (n = 1127), for 3 ‐ 5 years (in autumn or winter), median 2.96 years. "Ten tablets were mailed to participants annually (March‐August, determined by recruitment date) with instructions to take all tablets on a single day. Study staff confirmed by telephone the ingestion of study medication within 2 weeks. Subsequent dosing occurred within 2 weeks of the anniversary of the first dose."
Outcomes	Outcomes reported in abstract of publication Primary outcomes: falls and fractures. Secondary outcomes: serum 25‐hydroxycholecalciferol and intact parathyroid hormone levels.
Stated aim of study	Quote from the publication: "To determine whether a single annual dose of 500 000 IU of cholecalciferol administered orally to older women in autumn or winter would improve adherence and reduce the risk of falls and fracture."
Notes	"Study staff confirmed by telephone the ingestion of study medication." "The study was supported by project grant No. 251682 from the National Health and Medical Research Council and by the Australian Government Department of Health and Ageing. Financial Disclosures: none reported"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote from the publication: "Allocation was performed by an independent statistician using computer generated randomization of numbers performed in blocks of 500." Comment: sequence generation was achieved using computer random number generation.
Allocation concealment (selection bias)	Low risk	Quote from the publication: "Allocation was performed by an independent statistician. Treatment allocation status was e‐mailed directly to the hospital clinical trials pharmacist responsible for dispensing study medication." Comment: the participant allocations could not have been foreseen in advance of, or during, enrolment. Allocation was controlled by a central and independent randomisation unit.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote from the publication: "The participants and study staff were blinded to intervention group." Comment: 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.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote from the publication: "The participants and study staff were blinded to intervention group." Comment: the assessment of outcomes was not likely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias)	Low risk	Quote from the publication: "Enrollment and outcomes are shown in Figure 1. There was no difference between the treatment groups in the proportion who withdrew nor in the reasons for withdrawal." Comment: the numbers and reasons for dropouts and withdrawals in all intervention groups were described.
Selective reporting (reporting bias)	Low risk	Comment: all clinically relevant and reasonably expected outcomes were reported.
For‐profit bias	High risk	Quote from the publication: "Study medication was supplied by PSM Healthcare, Auckland, New Zealand." Comment: the trial was sponsored by the industry.
Other bias	Low risk	Comment: the trial appears to be free of other components that could put it at risk of bias.