J Clin Endocrinol Metab doi: 10.1210/clinem/dgaa808. .
Context: Bariatric surgery, particularly Roux-en-Y gastric bypass (RYGB), is associated with increased risk of osteoporotic fractures. It is unknown whether RYGB or sleeve gastrectomy (SG) have different effects on bone health.
Objective: To compare changes in bone mineral density and markers of bone turnover one year after SG and RYGB.
Design, setting, patients, and interventions: Randomized, triple-blind, single-center trial at a tertiary care center in Norway. Primary outcome was diabetes remission. Patients with severe obesity and type 2 diabetes were randomized and allocated (1:1) to SG or RYGB.
Main outcome measures: Changes in areal bone mineral density (aBMD) and bone turnover markers.
Results: Femoral neck, total hip, and lumbar spine aBMD, but not total body aBMD, decreased significantly more after RYGB (n=44) than after SG (n=48) [mean (95% CI) between group differences -2.8 % (-0.8 to -4.7), -3.0 % (-0.9 to -5.0), -4.2 % (-2.1 to -6.4), and -0.5 % (0.6 to -1.6), respectively]. The increase in procollagen type 1 N-terminal propeptide (P1NP) and C-telopeptide of type I collagen (CTX-1) were approximately 100% higher after RYGB than after SG, (both time x group, P<0.001). The changes in femoral neck, total hip and lumbar spine aBMDs and the changes in P1NP and CTX-1 were independently associated with the surgical procedure (all P<0.05) and not weight change.
Conclusions: RYGB was associated with greater reduction in aBMD and greater increase in bone turnover markers compared with SG. This finding could suggest greater skeletal fragility after RYGB.