title: The Vitamin D Assessment (ViDA) Study: design of a randomized controlled trial of vitamin D supplementation for the prevention of cardiovascular disease, acute respiratory infection, falls and non-vertebral fractures.
abstract: Observational studies have shown that low vitamin D status is associated with an increased risk of cardiovascular disease, acute respiratory infection, falls and non-vertebral fractures. We recruited 5110 Auckland adults, aged 50-84 years, into a randomized, double-blind, placebo-controlled trial to test whether vitamin D supplementation protects against these four major outcomes. The intervention is a monthly cholecalciferol dose of 100,000IU (2.5mg) for an estimated median 3.3 years (range 2.5-4.2) during 2011-2015. Participants were recruited primarily from family practices, plus community groups with a high proportion of Maori, Pacific, or South Asian individuals. The baseline evaluation included medical history, lifestyle, physical measurements (e.g. blood pressure, arterial waveform, lung function, muscle function), and a blood sample (stored at -80°C for later testing). Capsules are being mailed to home addresses with a questionnaire to collect data on non-hospitalized outcomes and to monitor adherence and potential adverse effects. Other data sources include New Zealand Ministry of Health data on mortality, hospitalization, cancer registrations and dispensed pharmaceuticals. A random sample of 438 participants returned for annual collection of blood samples to monitor adherence and safety (hypercalcemia), including repeat physical measurements at 12 months follow-up. The trial will allow testing of a priori hypotheses on several other endpoints including: weight, blood pressure, arterial waveform parameters, heart rate variability, lung function, muscle strength, gait and balance, mood, psoriasis, bone density, and chronic pain.
authors.affiliation: School of Population Health, The University of Auckland, Auckland, New Zealand. Electronic address: r.scragg@auckland.ac.nz.
authors.forename: Robert
authors.initials: R
authors.lastname: Scragg
authors.affiliation: School of Population Health, The University of Auckland, Auckland, New Zealand.
authors.forename: Debbie
authors.initials: D
authors.lastname: Waayer
authors.affiliation: School of Population Health, The University of Auckland, Auckland, New Zealand.
authors.forename: Alistair W
authors.initials: AW
authors.lastname: Stewart
authors.affiliation: School of Population Health, The University of Auckland, Auckland, New Zealand.
authors.forename: Carlene M M
authors.initials: CMM
authors.lastname: Lawes
authors.affiliation: Department of Public Health & General Practice, The University of Otago, Christchurch, New Zealand.
authors.forename: Les
authors.initials: L
authors.lastname: Toop
authors.affiliation: School of Population Health, The University of Auckland, Auckland, New Zealand.
authors.forename: Judy
authors.initials: J
authors.lastname: Murphy
authors.affiliation: Department of Public Health, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Kay-Tee
authors.initials: KT
authors.lastname: Khaw
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000339:Affect / Q000187:drug effects; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D002762:Cholecalciferol / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D050723:Fractures, Bone / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D005684:Gait / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects; D010349:Patient Compliance; D004856:Postural Balance / Q000187:drug effects; D012107:Research Design; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D011795:Surveys and Questionnaires
chemical_list: D002762:Cholecalciferol
keywords: Acute respiratory infection; Cardiovascular disease; Falls; Fractures; Prevention; Randomized controlled trial; Supplement; Vitamin D