Impact of marked weight loss induced by bariatric surgery on bone mineral density and remodeling

Abstract

Data about the impact of bariatric surgery (BS) and subsequent weight loss on bone are limited. The objective of the present study was to determine bone mineral density (BMD), bone remodeling metabolites and hormones that influence bone trophism in premenopausal women submitted to BS 9.8 months, on average, before the study (OGg, N = 16). The data were compared to those obtained for women of normal weight (CG, N = 11) and for obese women (OG, N = 12). Eight patients in each group were monitored for one year, with the determination of BMD, of serum calcium, phosphorus, magnesium, parathyroid hormone, 25-hydroxyvitamin D, insulin-like growth factor-I (IGF-I) and osteocalcin, and of urinary calcium and deoxypyridinoline. The biochemical determinations were repeated every three months in the longitudinal study and BMD was measured at the end of the study. Parathyroid hormone levels were similar in the three groups. IGF-I levels (CG = 332 ± 62 vs OG = 230 ± 37 vs OGg = 128 ± 19 ng/ mL) were significantly lower in the operated patients compared to the non-operated obese women. Only OGg patients presented a significant fall in BMD of 6.2% at L1-L4, of 10.2% in the femoral neck, and of 5.1% in the forearm. These results suggest that the weight loss induced by BS is associated with a significant loss of bone mass even at sites that are not influenced by weight overload, with hormonal factors such as IGF-I being associated with this process.

Bariatric surgery and bone metabolism: a systematic review

“…The 24-hour urinary calcium presents a significant reduction in operated patients (17)(18) even with adequate calcium replacement, which may be associated with a reduced intestinal absorption and, concomitantly, an increased need for a higher daily intake of calcium.…”

Bone Remodeling and Energy Metabolism: New Perspectives

“…Additionally, rapid weight loss leads to bone loss in sites that support weight, such as lumbar spine and proximal femur, but also in regions free of mechanical stress (i.e., 1/3 radius) (77,78). However, closer examination of the changes in body composition and in the hormonal profiles of the adipose tissue in obesity leads to some degree of ambiguity.…”

Bariatric surgery and bone disease: from clinical perspective to molecular insights

“…Bariatric surgery is commonly associated with a decrease in bone mass, [26][27][28] and also appears to be associated with an increase in fracture risk. 29,30 Until recently, the impact of major weight loss on bone metabolism was thought to result solely from a combination of mechanical and nutritional effects.…”