Effects of bariatric surgery on bone

Abstract

Bariatric surgery is a therapeutic resource for the management of morbid obesity; its use is growing rapidly. The intervention induces several changes in the hormonal and metabolicprofile of patients: decreased calcium absorption, falling levels of vitamin D, a secondary hyperparathyroidism which accelerates bone turnover; increase in the level of some cytokines such as adiponectin, GLP-1 and sclerostin, and decrease of others such as leptin, ghrelin, GIP and amylin. Estradiol falls due to decreased peripheral aromatization of testosterone. There is a decrease in the mechanical load on the skeleton, especially in the lower limbs. All this leads to loss of bone mass, which is variable and more marked in the proximal femur than in the spine. The risk of fracture increases, although not all series have shown this. Patients with marked decrease in body weight after bariatric surgery should be controlled carefully to insure a good supply of calcium and other nutrients, vitamin D supplementation, and the monitoring of bone mineral density.