Background: Many observational studies have reported an association between vitamin D and non-skeletal health outcomes. The D-Health Trial was launched to determine if supplementing the older population with high monthly doses of Vitamin D can prevent cancer and premature mortality. The intervention is ongoing but here we provide a detailed statistical analysis plan for the primary and secondary outcomes of the D-Health Trial. Methods/design: ) or placebo for five years. The primary outcome is all-cause mortality and the secondary outcomes are total cancer incidence and colorectal cancer incidence. These will be ascertained via linkage to death and cancer registries. The primary analysis for each outcome will follow an intention-to-treat approach; we will use flexible parametric survival models to investigate the association between supplementation and time to an event. We describe in detail sophisticated secondary analyses that consider non-compliance and contamination due to off-study supplementation. Conclusions: Publication of this statistical analysis plan in advance of the intervention's completion, and adherence to it, will avoid data-driven analyses of the primary and secondary outcomes and ensure robust reporting of outcomes. Clinical trial registration number: Australian New Zealand Clinical Trials Registry: ACTRN12613000743763. Registered on 4 July 2013.
|Authors||Waterhouse, Mary; English, Dallas R; Armstrong, Bruce K; Baxter, Catherine; Duarte Romero, Briony; Ebeling, Peter R; Hartel, Gunter; Kimlin, Michael G; McLeod, Donald S A; O'Connell, Rachel L; van der Pols, Jolieke C; Venn, Alison J; Webb, Penelope M; Whiteman, David C; Neale, Rachel E|
|Journal||Contemporary clinical trials communications|
|Funding Body||National Health and Medical Research Council|