More-than-minimal-trauma fractures are associated with low bone density: an 8-year prospective study.

Few studies have examined the relationship between more-than-minimal-trauma fractures and bone density. This study demonstrated that more-than-minimal-trauma fractures are associated with lower bone density similar to that seen in minimal trauma fractures. Men and women over 50 years with a more-than-minimal-trauma fracture should be investigated to exclude low bone density.

INTRODUCTION: The aim of this study was to assess the prevalence and predictors of low bone density in men and women with more-than-minimal-trauma fractures.

METHODS: In an Australian hospital, 630 community-dwelling men and women, 20 years of age or older, sustained a fracture due to more-than-minimal-trauma (force greater than a fall from standing height but less than high trauma). We studied 349 individuals who agreed to have a bone mineral density (BMD) scan. These participants were compared with 472 men and women with minimal trauma fractures.

RESULTS: Men and women with more-than-minimal-trauma fractures had significantly lower bone density than expected for their age, gender and weight (Z-scorespine  = -0.4 SD, 95 % confidence interval (CI), -0.5 to -0.3; Z-scorehip  = -0.5 SD, 95 % CI, -0.6 to -0.4). Almost 1 in 4 of those over 50 years of age had osteoporosis by BMD criteria. The independent predictors of low bone density (T-score <-2.0 SD) were age equal to or over 50 years (odds ratio (OR) = 5.97, 95 % CI, 3.34 to 10.65), low body weight <20 kg/m2 (OR = 3.44, 95 % CI, 1.32 to 8.94), a prior minimal trauma fracture (OR = 2.76, 95 % CI, 1.17-6.52) and in those over 50 years of age, an osteoporosis-associated condition (OR = 4.51, 95 % CI, 1.69 to 12.06). Men and women with more-than-minimal-trauma fractures had similar bone density (Z-score) compared to those with minimal trauma fractures.

CONCLUSIONS: Men and women over 50 years with a more-than-minimal-trauma fracture, especially those with low body weight, prior minimal trauma fracture or an osteoporosis-associated condition, should be investigated to exclude low bone density and its associated risk of subsequent fractures.