Trivedi 2003.

Study characteristics
Methods	Participants and investigators blinded until study ended, when pharmacy revealed coding 2055 of 2686 completed
Participants	Community‐based study, UK 2686 (2037 men and 649 women) mean 75 years, from register of British doctors and register of a general practice Inclusion criteria: age 65 to 85 years, living in the community, from British doctors' study register and general practice register in Ipswich Disease exclusions: contraindications to vitamin D supplementation e.g. renal stones, sarcoidosis, malignancy Drug exclusions: already taking vitamin D supplements
Interventions	1. Vitamin D3 (cholecalciferol) 100,000 IU Randomised 1345, completed 1038 2. Placebo: 1 capsule 4‐monthly Randomised 1341, completed 1017 Duration of treatment 5 years
Outcomes	1. Non‐vertebral fractures at 5 years 2. Hip fractures at 5 years 3. Vertebral fractures at 5 years 4. Falls 5. Self‐reported health 6. In a subgroup, 238 had measurement of PTH, 25(OH)D and heel ultrasound at 4 years 7. Compliance with trial medication 8. Adverse effects: death, death from cardiovascular disease, death from cancer
Notes	Discrepancy between text and table 5 in subgroup study (235 and 238 respectively)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	States "randomised", no other information provided
Allocation concealment (selection bias)	Low risk	Study conducted by post, states "participants and investigators were blinded to the treatment until the study ended, when Ipswich Pharmacy revealed the coding"