More than a quarter of postmenopausal women and men ≥50 years of age, as well as a significant number of younger patients, were found to have osteoporosis a decade after undergoing Roux-en-Y gastric bypass (RYGB) surgery, according to study results published in Bone. Furthermore, fragility fractures were also found to be common in this population.
Previous studies have shown that while RYGB is a bariatric surgery procedure commonly performed for treatment of morbid obesity, it may have negative effects on bone health. However, as there is limited information regarding the longer-term effects of RYGB on bone health, the goal of this study was to assess the prevalence of areal bone mineral density (aBMD) below the expected range for age, osteopenia, osteoporosis, and fragility fractures in individuals 10 years after the procedure.
The study included 122 patients (mean age, 50.3±9.0 years; 77% women) who underwent RYGB surgery between June 2004 and December 2006 in the Department of Morbid Obesity and Bariatric Surgery at the Oslo University Hospital in Norway. All patients attended an invited 10-year follow-up and were examined with dual-energy x-ray absorptiometry.
Of 122 patients, 63 were premenopausal women or men aged <50 years. In this subgroup of younger patients, aBMD values below the expected range for age (z score ≤-2.0) were evident in 5 patients (8%), and osteopenia (z score -1.1 to -1.9) was diagnosed in 19 patients (30%).
Among the 59 postmenopausal women or men aged ≥50 years, osteopenia (t-score -1.1 to -2.4) was evident in 30 patients (51%), and osteoporosis (t-score ≤-2.5) was evident in 16 patients (27%).
Independent risk factors for low aBMD 10 years after bariatric surgery included preoperative hypothyroidism, advanced age, postmenopausal status, body mass index <35 kg/m2, high procollagen type 1 N-terminal propeptide, or secondary hyperparathyroidism at 10-year follow-up.
Clinical low-energy fractures were reported in 18 patients (15%) during the 10 years after RYGB, including 11 postmenopausal women or men aged ≥50 years (19%) and 7 premenopausal women or younger men (11%). The prevalence of these fractures was significantly higher in patients with osteoporosis compared with those with aBMD values in the ostepenic or normal range (P =.023).
The researchers acknowledged several limitations of the study, including lack of preoperative medical history specific to bone health, bone turnover markers, and BMD measurements.
“Together, our findings indicate an increased risk of fracture 10 years after RYGB and support the need for long term follow-up focusing on bone health,” wrote the researchers.
Blom-Høgestøl IK, Hewitt S, Chahal-Kummen M, et al. Bone metabolism, bone mineral density and low energy fractures 10 years after Roux-en-Y gastric bypass. Bone. 2019;127:436-445.