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Vitamin D and Musculoskeletal Health

Authors: Anne E. Wolff, MD ; Andrea N. Jones, MA ; Karen E. Hansen, MDFaculty and Disclosures


Summary and Introduction


Vitamin D is critical for calcium homeostasis. Following cutaneous synthesis or ingestion, vitamin D is metabolized to 25(OH)D and then to the active form 1,25(OH)2D. Low serum vitamin D levels are common in the general population and cause a decline in calcium absorption, leading to low serum levels of ionized calcium, which in turn trigger the release of parathyroid hormone, promoting skeletal resorption and, eventually, bone loss or osteomalacia. Vitamin D deficiency is generally defined as a serum 25(OH)D concentration <25–37 nmol/l (<10–15 ng/ml), but the definition of the milder state of vitamin D insufficiency is controversial. Three recent meta-analyses concluded that vitamin D must be administered in combination with calcium in order to substantially reduce the risk of nonvertebral fracture in adults over the age of 50 years. Fracture protection is optimal when patient adherence to medication exceeds 80% and vitamin D doses exceed 700 IU/day. In addition to disordered calcium homeostasis, low vitamin D levels might have effects on cell proliferation and differentiation and immune function. Randomized, double-blind, placebo-controlled trials are needed to clarify whether vitamin D supplementation is beneficial in cancer, autoimmune disease and infection. This Review focuses on the pathophysiology, clinical correlates, evaluation and treatment of hypovitaminosis D.


Hypovitaminosis D, encompassing both vitamin D insufficiency and deficiency, is highly prevalent in the general population and has potentially deleterious musculoskeletal effects. Hypovitaminosis D results from several factors, including reduced cutaneous vitamin D synthesis as a consequence of sunscreen use,[1] increased skin pigmentation, inadequate sun exposure,[2] poor nutrition, comorbid diseases, such as celiac sprue, and the use of certain medications, such as anticonvulsants.[3] Using questions to assess diet and sun exposure in elderly individuals, one research group[4] reported associations between 25(OH)D levels and season of measurement, BMI, age, time spent indoors, vitamin D intake and plasma creatinine level. Here, we review the pathophysiology, clinical correlates, evaluation and treatment of hypovitaminosis D.

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