Association between change in BMD and fragility fracture in women and men

Abstract

Our objective was to estimate the relationship between longitudinal change in BMD and fragility fractures. We studied 3635 women and 1417 men 50-85 yr of age in the Canadian Multicentre Osteoporosis Study who had at least two BMD measurements (lumbar spine, femoral neck, total hip, and trochanter) within the first 5 yr of the study and fragility fractures (any, main, forearm/wrist, ribs, hip) within the first 7 yr. Multiple logistic regression was used to model the relationship between baseline BMD, BMD change, and fragility fractures. We found that, among nonusers of antiresorptives, independent of baseline BMD, a decrease of 0.01 g/cm(2)/yr in total hip BMD was associated with an increased risk of fragility fracture with ORs of 1.15 (95% CI: 1.01; 1.32) in women and 1.34 (95% CI: 1.02; 1.78) in men. The risk of fragility fractures in subgroups such as fast losers and those with osteopenia was better estimated by models that included BMD change than by models that included baseline BMD but excluded BMD change. Although the association between baseline BMD and fragility fractures was similar in users and nonusers of antiresorptives, the association was stronger in nonusers compared with users. These results show that BMD change in both men and women is an independent risk factor for fragility fractures and also predicts fracture risk in those with osteopenia. The results suggest that BMD change should be included with other variables in a comprehensive fracture prediction model to capture its contribution to osteoporotic fracture risk.

FIG. 1

Cumulative incidence of fragility fractures over 7 yr in women and men who are taking and not taking antiresorptive agents.

FIG. 2

Adjusted ORs and 95% CIs for a BMD decrease of 0.01 g/cm²/yr in women using or not using antiresorptive therapies in estimating fragility fracture. (A) Lumbar spine. (B) Femoral neck. (C) Total hip. (D) Trochanter. Forearm includes forearm and wrist fractures.

FIG. 3

Adjusted ORs and 95% CIs for a BMD decrease of 0.01 g/cm²/yr in men using or not using antiresorptive therapies in estimating fragility fracture. (A) Lumbar spine. (B) Femoral neck. (C) Total hip. (D) Trochanter. Forearm includes forearm and wrist fractures.

FIG. 4

Adjusted ORs and 95% CIs for a total hip BMD decrease of 0.01 g/cm²/yr in women and men in estimating any fragility fracture. Users and nonusers refer to the use of antiresorptive agents. “Follow-up 6+7 yrs” is predicting any incident fragility fractures in years 6 and 7 only and includes users and nonusers of antiresorptive agents. Only non-users of antiresorptive agents are included in the following subgroups: fast losers (first tertile of BMD change), those with the lowest baseline BMD (first tertile of baseline BMD); normal, osteopenic, and osteoporotic participants. “Fast losers” are in the lowest tertile of BMD change (BMD change < −0.0075 g/ cm²/yr in women; BMD change < −0.005184 g/cm²/yr in men). “Lowest baseline BMD” are in the lowest tertile of baseline BMD (BMD < 0.8312g/cm² in women; BMD < 0.9646 g/cm² in men).