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A randomized placebo-controlled trial of vitamin D supplementation for reduction of mortality and cancer: Statistical analysis plan for the D-Health Trial

Citation

Waterhouse, M and English, DR and Armstrong, BK and Baxter, C and Duarte Romero, B and Ebeling, PR and Hartel, G and Kimlin, MG and McLeod, DSA and O'Connell, RL and van der Pols, JC and Venn, AJ and Webb, PM and Whiteman, DC and Neale, RE, A randomized placebo-controlled trial of vitamin D supplementation for reduction of mortality and cancer: Statistical analysis plan for the D-Health Trial, Contemporary Clinical Trials Communications, 14 Article 100333. ISSN 2451-8654 (2019) [Refereed Article]


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Copyright 2019 The Authors. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/

DOI: doi:10.1016/j.conctc.2019.100333

Abstract

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: The D-Health Trial is a double-blind, randomized, placebo-controlled trial. Between February 2014 and May 2015, 21,315 people were randomized in a 1:1 ratio to receive monthly doses of either 60,000 IU of cholecalciferol (vitamin D3) 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.

Item Details

Item Type:Refereed Article
Keywords:cancer, mortality, randomized controlled trial, statistical analysis plan, vitamin D
Research Division:Medical and Health Sciences
Research Group:Public Health and Health Services
Research Field:Preventive Medicine
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Cancer and Related Disorders
UTAS Author:Venn, AJ (Professor Alison Venn)
ID Code:132291
Year Published:2019
Deposited By:Menzies Institute for Medical Research
Deposited On:2019-05-02
Last Modified:2019-06-06
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