vitamin D deficiency

Paracrine signalling

Secondary hyperparathyroidism

Vitamin

Calcium

Endocrinology

Receptor

Calcifediol

Bone remodeling

Osteomalacia

Calcitriol

Physiology

Autocrine signalling

Rickets

Internal medicine

Vitamin D and neurology

Parathyroid hormone

Medicine

Hyperparathyroidism

Calcium metabolism

Calcitriol receptor

Archives of Endocrinology and Metabolism

Vitamin D deficiency is a general health problem affecting individuals at all stages of life and on different continents. The musculoskeletal effects of vitamin D are well known. Its deficiency causes rickets, osteomalacia, and secondary hyperparathyroidism and increases the risk of fractures. Clinical and experimental evidence suggests that vitamin D performs multiple extraskeletal functions. Several tissues unrelated to calcium and phosphate metabolism express vitamin D receptor (VDR) and are directly or indirectly influenced by 1,25(OH)2D (calcitriol). Some also express the enzyme 1 alpha-hydroxylase (CYP27B1) and produce 1,25(OH)2D, inducing autocrine or paracrine effects. Among the pleiotropic effects of vitamin D are the regulation of cell proliferation and differentiation, hormone secretion, and immune function. In this review, we outline vitamin D physiology and the outcomes of recent large RCTs on its potential extraskeletal effects. Those studies exhibit a need for continued clinical analysis to elucidate whether vitamin D status can influence extraskeletal health. Longer longitudinal follow-up and standardized assays are crucial to better assess potential outcomes.

Vitamin D metabolism and extraskeletal outcomes: an update