Effect of ghrelin on bone mass density: The InChianti study

Introduction: Ghrelin is a stomach secreted hormone, believed to play an important role in energy balance and in food intake. Experimental studies have shown a positive effect of ghrelin on bone metabolism, but both in vivo and clinical findings have been contradictory. We aimed to investigate the effect of ghrelin on volumetric BMD in a large cohort of elderly subjects. Methods: We have studied 401 women (mean age 75.1. years, range 65-94) and 306 men (mean age 73.9. years, range 65-94) from the InChianti study, which included measurements of BMD using quantitative CT of the tibia and of body composition using bio impedancemetry. Serum ghrelin was measured using ELISA. We excluded participants with diabetes, hyperthyroidism, using hormone replacement or glucocorticoid therapy. We evaluated the correlation of ghrelin with total, trabecular, and cortical BMD using Pearson's coefficient, and linear regression models to estimate the association between ghrelin and BMD controlling for potential confounders. Results: In women, after correction for potential confounders, ghrelin was associated with trabecular BMD (β= 7.08, P <0.02), but not with total or cortical BMD. In men, adjusted multivariable models showed a nearly significant association between serum ghrelin and trabecular BMD (β= 4.99, P = 0.069) and no association with either cortical or total BMD. Conclusions: Serum ghrelin is positively correlated with trabecular BMD in a cohort of elderly healthy Italian women. The fact that trabecular is more metabolically active than cortical bone and the larger number of females might explain this selective association.