Vitamin D deficiency
, or hypovitaminosis D
, most commonly results from inadequate sunlight
exposure (in particular sunlight with adequate ultraviolet B
rays). Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D
, disorders limiting vitamin D absorption, and conditions impairing vitamin D conversion into active metabolite
s—including certain liver
, and hereditary disorders
. Deficiency impairs bone mineralization
, leading to bone softening diseases as rickets
in children. It can also worsen osteomalacia
in adults, leading to an increased risk of bone fractures.
Muscle weakness is also a common symptom of vitamin D deficiency, further increasing the risk of fall and fracture in adults.