Bariatric surgery and the risk for osteoporotic fractures - a population-based study

Bariatric surgery (BS) is an effective procedure for sustained weight reduction. However, it may increase fracture risk. We aim to investigate the risk posed by BS for proximal femur and vertebral osteoporotic fractures.

A retrospective cohort study of 17,971 patients, aged 40 (SD12.7), who underwent BS was conducted. The incidence of femoral and vertebral fractures, in the six-year prior- and-post the BS was assessed. The effects of the BMI change, the type of BS performed and the treatment with osteoporosis medications or nutritional supplements was evaluated.

The incidence of both proximal femoral and vertebral fractures rose in the 6 years following BS, for men and women alike (OR 4.073, 95%CI[2.329,7.546], p.<0.001 for femur and OR 1.855, 95%CI[1.453,2.381], p.<0.001 for vertebra). The effect remained significant when controlled for the increasing age. The mean BMI loss was 10.7 (SD6.4). Weight reduction by itself was not related to the incidence of fracture. The time elapsed between the BS and the incidence of fracture was not affected by the surgical technique. However, for femoral, and not vertebral fractures, the probability to sustain a fracture was higher after three-years from the BS (0.07% in post-BS years 0-3 vs. 0.23% in post-BS years 3-6, adjusted OR 0.584, 95%CI[0.337,0.990], p = 0.035).

BS was found to increase both femoral and vertebral fracture risk. The incidence of fracture was independent of the magnitude of weight loss and rose as time from surgery increased. Malabsorptive surgery posed a greater risk factor for proximal femoral fractures.