Purpose of review Several recent studies have documented a rising prevalence of rickets in infants and subclinical vitamin D deficiency in people across the age spectrum. This article presents an update on vitamin D deficiency, highlighting potential detrimental effects on bone, but also exploring important extraskeletal effects.

Recent findings Vitamin D deficiency manifests itself most commonly as rickets in children and osteomalacia or osteoporosis in adults. Recent observations of a strikingly high prevalence of vitamin D deficiency have spanned age groups and global regions. Risk factors for this problem have also been identified, such as African American race and obesity. In response, new pediatric guidelines have been developed that have been met with controversy. An important recent observation is that dietary calcium intake in infants with nutritional rickets plays a more significant role in skeletal healing than has been previously recognized. Other recent observations are that sunlight exposure may prevent hip fractures in postmenopausal women in addition to men and women living in the community. Recent reports and reviews also explore the role of vitamin D in the inhibition of cell proliferation and immunomodulation.

Summary Even though vitamin D deficiency has been thought to be obsolete in developed countries such as the United States, recent data suggest that this diagnosis may exist in epidemic proportions. Chronic vitamin D deficiency may be associated with a susceptibility to hypertension, multiple sclerosis, and various malignancies, problems beyond the more commonly recognized skeletal manifestations.