Causes of Vitamin D Deficiency58
| Causes | Example |
|---|---|
| Reduced skin synthesis | Sunscreen, skin pigment, season/latitude/time of day, aging, skin grafts |
| Decreaseed absorption | Cystic fibrosis, celiac disease, whipple disease, Crohn disease, gastric bypass, medications that reduce cholesterol absorption |
| Increased sesquestration | Obesity |
| Increased catabolism | Anticonvulsant, glucocorticoid, highly active antiretroviral treatment, and some immunosuppressants |
| Breastfeeding | |
| Decreased synthesis of 25-hydroxyvitamin D | Hepatic failure |
| Increased urinary loss of 25-hydroxyvitamin D | Nephrotic proteinuria |
| Decreased synthesis of 1,25-dihydroxyvitamin D | Chronic renal failure |
| Heritable disorders | Genetic mutations causing rickets, or vitamin D resistance |
| Acquired disorders | Tumor-induced osteomalacia, primary hyperparathyroidism, hyperthyroidism, granulomatous disorders such as sarcoidosis, tuburculosis, and some lymphomas |