About one-half of women with incident fractures have BMD above the WHO diagnostic threshold of osteoporosis. In the OFELY study, low BMD, increased markers of bone turnover, and prior fracture could be used to identify, within osteopenic women, those at high risk of fracture.
Introduction: Recent data suggest that about one-half of women with incident fractures have BMD above the World Health Organization (WHO) diagnostic threshold of osteoporosis (T score<or=-2.5). We aimed to identify, within osteopenic women, those at high risk of fracture.
Materials and methods: In the 671 postmenopausal women (mean age: 62 years) belonging to the Os des Femmes de Lyon (OFELY) population-based prospective cohort, we measured at baseline BMD by DXA at the spine and total hip, bone turnover markers (BTM) and clinical risk factors for osteoporosis. All fragility vertebral or nonvertebral fractures, confirmed by radiographs, were assessed during a median follow-up of 9.1 years (IQ: 2.3).
Results: 158 incident fractures were recorded in 116 women: 8% in normal, 48% in osteopenic, and 44% in osteoporotic women. Among osteopenic women, low BMD (-2.5<T score<or=-2.0) was associated with an increased fracture risk with an age-adjusted hazard ratio (HR) of 2.5 (1.3-4.6). In addition, age, prior fracture, and high BTM-but not other risk factors-were independently associated with an increased fracture risk with an age-adjusted HR of 2.2 (1.2-4.3) for prior fractures and 2.2 (1.4-3.8) for bone alkaline phosphatase (BALP) in the highest quartile. In the whole group of osteopenic women, a large majority of incident fractures occurred in those with a low BMD, prior fractures, or BALP in the highest quartile, with an age-adjusted HR of 5.3 (2.3-11.8). The 10-year probability of fracture in osteopenic women was 26% if at least one predictor was present, contrasting with 6% in those without any of the three risk factors.
Conclusions: In postmenopausal women with osteopenia, low BMD, increased BTM, and prior fracture are associated with an increased risk of fracture in the subsequent 10 years. Their assessment may play an important role in identifying women at high risk of fracture who could not be adequately detected by BMD measurement alone and who may benefit from a therapeutic intervention.