Edward Gorham, PhD, UC San Diego School of Medicine, describes the prevalence of vitamin D deficiency in terms of sun avoidance and person, place, and time. He identifies key items of evidence suggesting a protective association between sunlight, vitamin D, and risk of type 1 diabetes. He also lists the ways in which addressing vitamin D deficiency can have a positive impact on public health. Series: "Vitamin D for Public Health - Integrating Sunshine, Supplements and Measurement for Optimal Health 2014" [Health and Medicine] [Show ID: 29083]