Why patients fractured with higher bone mineral density?

Abstract

Objective: The aim of this cross-sectional study was to determinate the clinical risk factors associated with fractures in Chinese population with a higher bone mineral density (BMD) [T-score > –2.0]. Methods: All post-menopausal women with age of more than 50 years referred to Osteoporosis Clinic with lowtraumatic fractures were included in the analysis. All subjects underwent a structured evaluation and BMD was measured by dual-energy X-ray absorptiometry. Common risk factors related to osteoporosis were identified and compared between patients with T-score ≤ –2.0 and > –2.0. Results: A total of 450 patients with fracture were assessed. The mean age was 67±8 years. Of the patients, 65% (n=293) of the patients presented with T-score ≤ –2.0 (low BMD group) and 35% (n=157) had T-score > –2.0 (high BMD group). Subjects of high BMD group were younger (63±8 vs 69±7 years, P<0.001), had lower body mass index (14.32±3.12 vs 15.42±4.11 kg/m2, P<0.05), shorter period of post-menopause time (11±8 vs 19±7 years, P<0.001), and lower oral diet calcium intake (643±272 vs 713±283 mg/day, P<0.05). More of them were current alcohol drinkers (11.5% vs 5.1% respectively, P<0.05) and smokers (8.3% vs 3.8% respectively, P<0.05). This group of patients had significantly higher serum parathyroid hormone (44.32±12.92 vs 40.41±11.73 pg/mL, P<0.05) but their serum calcium levels were similar to the lower BMD group (2.30±0.13 vs 2.30±0.11 mmol/L). Conclusions: Our findings showed that a significant proportion of patients sustained fractures with higher BMD. Some clinical risk factors identified in this group are modifiable. Public health education for bone health promotion should focus not only on osteoporotic patients, but also on individuals with higher BMD.