Rate of forearm bone loss is associated with an increased risk of fracture independently of bone mass in postmenopausal women: the OFELY study

Abstract

BMD is a major determinant of the risk of fragility fractures, but the role of the rate of postmenopausal bone loss is still unclear. In 671 postmenopausal women from the OFELY cohort, we found that the rate of bone loss was significantly associated with fracture risk independently of other well-known predictors including BMD and previous fractures.

Introduction: The level of BMD is a major determinant of the risk of fragility fractures, but the role of the rate of postmenopausal bone loss is still unclear.

Materials and methods: In the OFELY study, we analyzed the risk of fracture in 671 postmenopausal women (mean age, 62.2 +/- 9 years), according to the rate of bone loss. BMD was measured annually by DXA at the forearm, with a mean number of measurements of 10.3 +/- 2.6. Peripheral fractures, all confirmed by radiographs, were prospectively registered, and vertebral fractures were evaluated with spine radiographs every 4 years.

Results: During a median (interquartile range [IQ]) of 11.2 years (11-12.3 years) of follow-up, 183 incident fragility fractures including 53 vertebral and 130 nonvertebral fractures were recorded in 134 women. The annual median +/- IQ rate of bone loss, calculated from the slope, was -0.30 +/- 0.76% at the mid-radius, -0.55 +/- 0.79% at the distal radius, and -0.40 +/- 0.96% at the ultradistal radius. Women with incident fracture had a rate of bone loss (before fracture) higher by 38-53% than those without fracture (p = 0.0003-0.016). Using multivariate Cox regression models, we found that bone loss in the highest tertile at the mid-radius, distal radius, and ultradistal radius was associated with a significant increased risk of all fractures with an hazard ratio from 1.45 to 1.70 (p = 0.02 to p = 0.009 after adjusting for age, previous fractures, maternal history of fracture, physical activity, grip strength, falls, and baseline BMD).

Conclusions: The rate of bone loss in postmenopausal women is significantly associated with fracture risk independently of other well-known predictors such as BMD and history of fractures.