GIP has an inhibitory effect on bone resorption and possibly promote osteosynthesis. GIP reduces CTX-I independently of insulin. Loss-of function GIPR gene polymorphism has been found to be inversely associated with BMD and positively associated with an elevated risk of fractures. The antiresorptive effects of GIP are preserved in hypoparathyroid patients, supporting that GIP has PTH-independent effects on bone. This evidence concerns the gene PTH and hypoparathyroidism.