Vitamin D tests were originally developed for investigation of rickets, osteomalacia and other metabolic bone disorders. In recent years the number of requests for vitamin D tests has increased dramatically. Most of these requests are unrelated to metabolic bone disease, and have arisen because of reported associations between various disease states (cancers,
cardiovascular disease, diabetes, autoimmune disorders and infectious diseases) and lower vitamin D concentrations.
However, a causal link has yet to be demonstrated for any of these conditions. The Institute of Medicine, following a comprehensive review of the evidence, concluded that “For extraskeletal outcomes, including cancer, cardiovascular disease, diabetes, and autoimmune disorders, the evidence was inconsistent, inconclusive as to causality, and insufficient to inform nutritional requirements. Randomized clinical trial evidence for extraskeletal outcomes was limited and generally uninformative.”
A recent review for the Ontario Ministry of Health has concluded that there is little evidence that it is useful to measure vitamin D concentrations in patients without symptoms of metabolic bone disease.