Prof Robert Scragg is Head of the School of Population Health at the University of Auckland where he has worked since 1984. He is a graduate of Adelaide Medical School and trained in epidemiology in the late 1970s at the CSIRO Division of Human Nutrition, Adelaide, South Australia, where he published the hypothesis that sun light and vitamin D may protect against cardiovascular disease. He is the principal investigator of the Vitamin D Assessment (ViDA) Study. The main aims of the study were to determine if monthly doses of vitamin D3 (100,000 IU) prevent cardiovascular disease, respiratory infections, falls and fractures. The study randomised 5,108 participants aged 50-84 years in 2011-12, and follow-up stopped at 31 July 2015. The main results from the ViDA study have been published and will be discussed in the context of recent publications on vitamin D and health.