Long-Term Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density: a 4-Year Longitudinal Study

Bone mineral density (BMD) declines in the initial years after bariatric surgery, but long-term skeletal effects are unclear and comparisons between sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are rare.An observational longitudinal study of obese patients undergoing SG or RYGB was performed. Whole-body (WB) BMD, along with BMD of the total hip (TH), femoral neck (FN), and lumbar spine (LS), was measured by dual-energy X-ray absorptiometry (DXA) before surgery and yearly thereafter for 4 years. Calciotropic hormones were also measured.Forty-seven patients undergoing RYGB surgery and 28 patients undergoing SG were included. Four years after RYGB, BMD declined by 2.8 ± 5.8% in LS, 8.6 ± 5% in FN, 10.9 ± 6.3% in TH, and 4.2 ± 6.2% in WB, relative to baseline. For SG, BMD declined by 8.1 ± 5.5% in FN, 7.7 ± 6% in TH, 2.0 ± 7.2% in LS, and 2.5 ± 6.4% in WB after 4 years, relative to baseline. Vitamin D levels increased with supplementation in both groups. Whereas parathyroid hormone levels increased slightly in the RYGB group, they decreased modestly in the SG group (P 0.05 in both groups).Bone loss after 4 years was comparable between the two procedures, although RYGB was associated with a slightly greater decrease at the TH than SG. Bone health should therefore be monitored after both RYGB and SG.