aetiology of vitamin D deficiency
Last edited 09/2018
Reduced intake of vitamin D:
- lack of sunlight - deficiency of vitamin D3 - cholecalciferol
- dietary lack of vitamin D3 - ergocalciferol
- fat malabsorption - e.g. coeliac disease, pancreatic insufficiency, extrahepatic biliary obstruction
Reduced hepatic production of 25(OH)D3:
- severe chronic liver disease - interference with synthesis of vitamin D binding protein
- induction of hepatic P-450 enzymes accelerating rate of degradation e.g. phenytoin, carbamazepine
- nephrotic syndrome - excess excretion of vitamin D binding protein
Reduced renal production of calcitriol - 1,25(OH)2 D3:
- deficiency of 1 alpha hydroxylase:
- hereditary - vitamin D dependent rickets type I
- chronic renal failure
- suppression of 1 alpha hydroxylase action:
- deficiency of PTH - hypoparathyroidism
- end organ resistance - pseudohyperparathyroidism
Resistance to calcitriol:
- vitamin D dependent rickets type II
Reference: