Lappe 2007.

Methods	Randomised, double‐blind, placebo‐controlled trial using parallel group design (three intervention groups).
Participants	Country: United States. Number of participants randomised: 1179 healthy postmenopausal white women, 55 years of age and older (mean 66.7). Inclusion criteria: age > 55 years, at least four years past last menses; in generally good health, living independently in the community, and weighing less than 300 pounds. Exclusion criteria: a medical diagnosis of any chronic kidney disease, Paget's or other metabolic bone disease, and history of cancer except for superficial basal or squamous cell carcinoma of the skin and other malignancies treated curatively more than 10 years prior to entry into the trial.
Interventions	Participants were randomly assigned to receive: Intervention group 1: vitamin D3 (1000 IU) plus calcium (1400 to 1500 mg) daily (n = 446); Intervention group 2: vitamin D3 placebo plus calcium (1400 to 1500 mg) daily (n = 445); Intervention group 3 (Control group): placebo, consisting of both vitamin D3 placebo and a brand‐specific calcium placebo daily (n = 288); for a four‐year period.
Outcomes	The primary outcome was fracture incidence, and the principal secondary outcome was cancer occurrence.
Stated aim of study	"To determine the efficacy of calcium alone and calcium plus vitamin D in reducing incident cancer risk of all types."
Notes	"Compliance with trial medication was assessed at six months intervals by bottle weight. Mean adherence (defined as taking 80% of assigned doses) was 85.7% for the vitamin D component of the combined regimen and 74.4% for the calcium component." The calcium supplements were provided by Mission Pharmacal (San Antonio, TX) and GlaxoSmithKline (Parsippany, NJ). The vitamin D3 was obtained from Tishcon Corporation (Westbury, NY). Additional information on mortality was received through personal communication with Professor Joan M Lappe (21.11.2007).
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.
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.
Incomplete outcome data (attrition bias) All outcomes	High risk	The numbers and reasons for dropouts and withdrawals in all intervention groups were not described.
Selective reporting (reporting bias)	Low risk	Pre‐defined, or clinically relevant and reasonably expected outcomes are reported on.
Industry bias	Unclear risk	The calcium supplements were provided by Mission Pharmacal (San Antonio, TX) and GlaxoSmithKline (Parsippany, NJ). The vitamin D3 was obtained from Tishcon Corporation (Westbury, NY).
Other bias	Low risk	The trial appears to be free of other components that could put it at risk of bias.