Understanding the Variables That Affect Vitamin D Status

Location, pollution, weight, and health affect your ability to absorb, store, and make use of vitamin D.

It has been estimated that 30% of the U.S. population (and 9% of U.S. children) are vitamin D insufficient or deficient. Among those at risk for vitamin D deficiency are people who are older, live at higher latitudes, or have darker skin, and those whose religious observance requires them to cover large areas of skin. A recent review provides additional information on factors that affect an individual's vitamin D status.

Exposure. The authors indicate that during prolonged exposure to ultraviolet B (UVB; 290–320 nm) radiation, only about 10% to 15% of 7-dehydrocholesterol is converted to vitamin D₃ because of its breakdown to inactive compounds. Several environmental factors influence vitamin D metabolism. For example, in certain regions of …

Reviewing Author

Craig A. Elmets, MD

Disclosures

Consultant / Advisory board Astellas Pharmaceuticals

EquityVaxin

Grant / Research support NIH; NIH/NCI; Veteran’s Administration; Ferndale Laboratories; Kyowa Hakko Kirin Pharma, Inc.

Editorial boards Cancer Prevention Research; Photodermatology, Photoimmunology, & Photomedicine; UpToDate; eMedicine; Journal of Dermatological Sciences; JAMA Dermatology

Leadership positions in professional societies American Academy of Dermatology (Vice Chair, Committee on Science and Research); Photomedicine Society (Board of Directors)