What are the risk factors for Vitamin D deficiency?

According to an analysis from the National Health and Nutrition Examination Survey (NHANES 2001–2018) (Cui et al., Frontiers in Nutrition, 2022), about one-quarter of people in the United States have vitamin D levels below 50 nmol/L, with deficiency more common in non-Hispanic Black and Hispanic adults, people with obesity, and those who consume less vitamin D–fortified milk. Risk factors for vitamin D deficiency include limited sun exposure, older age, darker skin, obesity, low intake of vitamin D–containing foods, and certain gut, liver, or kidney conditions that affect vitamin D absorption or activation (National Institutes of Health, Office of Dietary Supplements, Vitamin D – Fact Sheet for Health Professionals, 2022).