AKA: Hypovitaminosis D<unk>  leads to impaired bone mineralization and diseases such as:
Rickets in children
Osteomalacia and osteoporosis in adults
Rickets in children
Osteomalacia and osteoporosis in adults
Gained from diet, supplements, or sunlight exposure
Fortified foods (mainstay, eg milk, cereals), supplements, fatty fish, egg yolks, fish liver oil, and some mushrooms
Synthesis of vitamin D occurs in the skin through exposure to ultraviolet B radiation from sunlight
Hydroxylated in liver→ 25-hydroxyvitamin D, which is further hydroxylated in kidney or extrarenally→ 1,25-dihydroxyvitamin D (active form)
Second hydroxylation regulated by PTH, serum calcium, and phosphorus levels
Vitamin D acts to:
Stimulate intestinal calcium absorption
Maintain adequate phosphate levels for bone development
Regulate cell growth proliferation and apoptosis
Modulate immune function and inflammation reduction
Fortified foods (mainstay, eg milk, cereals), supplements, fatty fish, egg yolks, fish liver oil, and some mushrooms
Synthesis of vitamin D occurs in the skin through exposure to ultraviolet B radiation from sunlight
Second hydroxylation regulated by PTH, serum calcium, and phosphorus levels
Stimulate intestinal calcium absorption
Maintain adequate phosphate levels for bone development
Regulate cell growth proliferation and apoptosis
Modulate immune function and inflammation reduction
Inadequate dietary intake, inadequate sunlight exposure
Especially individuals with higher melanin content living in colder climates
Impaired vitamin D absorption
Crohn's disease, cystic fibrosis, pancreatic insufficiency
Impairment in conversion of vitamin D into active metabolites
Renal Failure, Liver failure
Especially individuals with higher melanin content living in colder climates
Crohn's disease, cystic fibrosis, pancreatic insufficiency
Renal Failure, Liver failure
Vitamin D deficiency
Hypocalcemia
Vitamin A toxicity
Hyperparathyroidism
Paget's disease of bone
Hypophosphatemia
Vitamin A deficiency
Malignancy