Increase of bone resorption and the parathyroid hormone in postmenopausal women in the long-term after Roux-en-Y gastric bypass

Abstract

Background: The effects of Roux-en-Y Gastric Bypass (RYGB) on bone in the long-term remains unclear. We assessed bone metabolism and bone mineral density (BMD) 1 to 5 years after RYGB.

Methods: We designed a retrospective cohort study in 26 postmenopausal women (58.0+/-3.9 years old) with RYGB 3.5+/-1.1 years before (body mass index (BMI) 29.5+/-3.8 kg/m2, presurgery 43.6+/-5.5 kg/m2) and 26 nonoperated women (57.5+/-4.7 years old, BMI 29.2+/-4.1 kg/m2) matched by age and BMI. The main measures were BMD, serum carboxy telopeptide (CTx), total alkaline phosphatases (ALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), and ghrelin.

Results: RYGB group, compared to nonoperated women, had higher CTx (0.71+/-0.21 vs. 0.43+/-0.15 ng/ml; P<0.01) and PTH (68.3+/-35 vs. 49.4+/-16 pg/ml; P=0.02). There were no differences between RYGB and nonoperated women in: calcium and vitamin D intake (759+/-457 vs. 705+/-460 mg/day; 176+/-160 vs. 111+/-86 UI/day), ghrelin (763+/-336 vs. 621+/-274 pg/ml), ALP (101+/-22 vs. 94+/-25 UI/l), 25OHD (18.8+/-7.6 vs. 17.4 +/- 5.9 ng/ml), lumbar spine BMD (1.059+/-0.32 vs. 1.071+/-0.207 g/cm2), or femoral neck BMD (0.892+/-0.109 vs. 0.934+/-1.1 g/cm2).

Conclusions: RYGB is associated to high bone resorption and hyperparathyroidism prevalence in postmenopausal women in the long-term. This occurs independently of the intake of calcium, vitamin D status, or ghrelin and does not seem to affect BMD after RYGB.