Abstract
Vitamin D deficiency has traditionally been viewed as a metabolic bone disease by bioarchaeologists and considered primarily in terms of the development of specific musculoskeletal changes used for diagnosis in paleopathological research. These skeletal manifestations are usually interpreted as representing general ill-health. Clinical research shows that vitamin D is also integral to a number of extra-skeletal physiological processes including immunoregulation, blood pressure homeostasis, cell division, and programmed cell death. Vitamin D deficiency and sub-clinical insufficiency are thought to be risk factors for infectious and autoimmune diseases, as well as certain cancers and cardiovascular diseases. Epidemiological work indicates that the skeletal manifestations of vitamin D deficiency represent the extreme end of a spectrum of morbidity associated with negative health outcomes, including increased risk for secondary tuberculosis. This article provides a review of clinical research on the extra-skeletal roles of vitamin D and the pathological consequences of poor vitamin D status. Additionally, it presents an interpretive model for bioarchaeological analyses of rickets and osteomalacia for consideration of the whole-body impact of poor vitamin D nutriture and possible comorbidities that may have affected the wider population. (C) 2016 Wiley Periodicals, Inc.