Trivedi 2003.
| Study characteristics | ||
| Methods | RCT. Stratified by age and sex | |
| Participants | Setting: Suffolk, United Kingdom N = 2686 Sample: recruited from British doctors study register and 1 GP patient register (24% women) Age (years): mean 75 (SD 5), range 65 to 85 Inclusion criteria: aged 65 to 85 years Exclusion criteria: already taking vitamin D supplements; conditions with contraindications for vitamin D supplementation, e.g. renal stones, sarcoidosis, or malignancy | |
| Interventions | 1. Oral vitamin D3 supplementation (100,000 IU cholecalciferol) 1 capsule every 4 months for 5 years 2. Control: matching placebo 1 capsule every 4 months for 5 years | |
| Outcomes | 1. Number of people falling
2. Number sustaining a fracture 3. Adverse events Other outcomes reported but not included in this review |
|
| Duration of the study | 5 years | |
| Notes | Although fracture and major illness data collected every 4 months after capsules sent out, falls data not collected until end of study. Falls not mentioned in statistical analysis section of methods. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "randomised after stratification by age and sex" Comment: probably done since earlier reports from the same investigators clearly describe use of random sequences. |
| Allocation concealment (selection bias) | Low risk | Quote: "Ipswich pharmacy revealed the coding" at the end of the study. So assume randomised centrally. |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Placebo‐controlled randomised trial |
| Blinding of outcome assessment (detection bias) Falls and fallers | Low risk | Falls reported by participants who were blind to their group allocation (placebo‐controlled trial) |
| Blinding of outcome assessment (detection bias) Fractures | Unclear risk | Fractures reported by participants who were blind to their group allocation (placebo‐controlled trial). Confirmation of fracture outcomes appears to have occurred only in participants who died, and the fracture was recorded on the death certificate. |
| Incomplete outcome data (attrition bias) Fallers | Low risk | SeeAppendix 3 for method of assessment |
| Risk of bias in recall of falls | High risk | Retrospecive recall over 12‐month period at the end of 5 years |