By Reuters Staff
NEW YORK (Reuters Health) - Bone strength increases in the year after Roux-en-Y gastric bypass (RYGB) surgery in patients with and without type 2 diabetes, researchers from Norway report.
Previous studies reported reductions in areal bone mineral density (aBMD) and increases in bone turnover and fracture rate after RYGB surgery, but little is known about changes in bone material strength following surgery.
Dr. Ingvild K. Blom-Hogestol of Oslo University Hospital and colleagues evaluated the bone-material-strength index - a normalized measure of bone indentation depth - at the mid-shaft of the right tibia, aBMD and bone turnover markers in 34 morbidly obese individuals (13 with type 2 diabetes) one year after they underwent RYGB.
By then, participants had lost a mean 33.9 kg (28.3% of total body weight), the researchers report in Bone, online October 5. Mean vitamin D levels were unchanged after one year, but the number of participants with vitamin D deficiency had decreased from 11 preoperatively to seven.
Bone turnover markers increased significantly among patients with and without type 2 diabetes.
During this interval, aBMD decreased by 3.9% in the lumbar spine, 8.2% in the femoral neck, 11.6% in the total hip, and 9.4% in the total body, with no significant differences between participants with and without type 2 diabetes.
Despite these changes, bone material strength increased significantly from 78.1 preoperatively to 82.0 one year after RYGB surgery, an increase of 6.3%.
These increases in bone material strength did not differ significantly between patients with and without type 2 diabetes, but larger decreases in hemoglobin A1c among those with diabetes were associated with greater increases in bone material strength.
Dr. Blom-Hogestol did not respond to a request for comments.