Effect of incretins on skeletal health.

PURPOSE OF REVIEW: The incretin hormones, glucagon like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), have been shown to decrease bone resorption in humans. The aim of this review is to collate evidence and current advances in the research within the last year on the effect of incretins on skeletal health.

RECENT FINDINGS: Preclinical studies show potential direct beneficial effects on bone by GLP-1 and GIP, however real world epidemiological data show no effects of GLP-1 receptor analogues on fracture risk. This may be due to the weight loss accompanied by GLP-1 treatment which may have detrimental effects on bone. GIP is shown to reduce bone resorption and increase bone formation. Further evidence suggests an additive effect of GIP and glucagon like peptide-2, which could affect bone by different mechanisms.

SUMMARY: GIP and GLP-1 based therapies are more widespread used and may have potential beneficial effects on bone, possibly counterbalanced by weight loss. Long-term effects and side-effects of GIP or GIP/ GLP-2 co-administration remain to be elucidated, and longer term treatment trials are needed.