Poster Presentation 33rd ASM of the Australian & New Zealand Bone & Mineral Society 2023

Skeletal Age (SA) is conceptually defined as the age of an individual's skeleton resulting from a fragility fracture or exposure to risk factors for fracture. Low bone mineral density (BMD). a well-established fracture risk factor is in turn associated with an increased mortality risk. This study sought to quantify the association between BMD and mortality by using the SA metric.

This study was based on the online data from the Osteoporotic Fractures in Men Study (n= 5994) and the Study of Osteoporotic Fractures (n= 7960). BMD was measured by DXA. The incident fractures were radiologically ascertained, and deaths by reviewing death certificates. Cox's proportional hazard model was used to quantify the association between femoral neck BMD and mortality from which years of life loss (YLL) were estimated. SA was calculated as the sum of chronological age and YLL.

During a median follow-up of 12.4 years (IQR: 7.0, 17.2) and 9.3 years (4.4, 15.2), 1,085 men and 3,879 women had sustained a fracture, yielding the incidence rate of 16 fractures/1,000 person-years (95% CI: 15, 17), and 45 fractures/1,000 person-years (44, 46), respectively. There were 3,612 men and 5,665 women who died during a median follow-up of 14 years. Overall, individuals with a higher risk of fractures were associated with an increased risk of death and thus had higher SA. Specifically, a 70-year man with a medium- and high-risk profile were estimated to have a SA of 71.4 (~ 1.4 YLL), and 72.5 (~ 2.5 YLL) years old, respectively (Table).

These data indicate that low BMD is associated with an increased mortality risk, and this association is an indication of bone fragility which can be measured by the SA metric. By using this metric, medical professionals can better communicate the severity of bone fragility to patients, enhancing doctor-patient fracture risk communication.