| Chronic kidney disease |
| Impaired calcitriol production |
| Hyperphosphatemia |
| Hypocalcemia |
| Decreased calcium intake |
| Calcium malabsorption |
| Vitamin D deficiency |
| Bariatric surgery |
| Celiac disease |
| Pancreatic disease (fat malabsorption) |
| Renal calcium loss |
| Idiopathic hypercalciuria |
| Loop diuretics |
| Inhibition of bone resorption |
| Bisphosphonates |
| Denosumab |
| Hungry bone syndrome |
