Incidence of vertebral fracture in a cohort of Australian women: data from the Geelong Osteoporosis Study

Abstract

Summary

This study reports the incidence rate of vertebral fractures (6.78 fractures per 1000 person-years) in a representative cohort of Australian women and identifies advanced age, prior low trauma fracture, a history of falls and an increase in bone turnover as potential key predictors.

Purpose

This study aimed to assess prevalence and incidence rates of objectively identified vertebral fracture in a representative cohort of Australian women and explore associated factors.

Methods

Serial lateral vertebral assessments (Lunar Prodigy) were performed in the Geelong Osteoporosis Study (median interval duration 6.86 years; interquartile range: 6.13–7.32). Prevalent and incident vertebral fractures were defined using Genant semi-quantitative approaches, with rates age-standardised to the 2006 Australian population in alignment with the period of data collection. Demographic, clinical and lifestyle factors were collected via a combination of in-person assessment and questionnaires, and logistic regression was used to investigate relationships between these factors and fracture outcomes.

Results

At baseline, 1013 women (ages 20–93 years) were measured and 23 individuals were identified with a prevalent vertebral fracture; 701 women were assessed at follow-up, 19 of whom experienced an incident vertebral fracture. The age-adjusted prevalence at baseline was 2.0% (1.3–2.8), and the age-adjusted incidence rate was 6.78 (4.19–9.37) fractures per 1000 person-years. Prior fracture (OR 6.70, 95% CI 2.55–17.64), lower lumbar spine bone mineral density (OR 0.01, 95% CI 0.00–0.13) and limited physical function (OR 3.80, 95% CI 1.47–9.83) were independently associated with prevalent fracture. In contrast, increased age (OR 1.12, 95% CI 1.06–1.17), prior fracture (OR 3.51, 95% CI 1.15–10.76), a history of falls (OR 3.55, 95% CI 1.29–9.79) and increased markers of bone formation (OR 1.02, 95% CI 1.00–1.04) were associated with incident fracture.

Conclusions

This study reports the incidence rate of vertebral fractures in a representative cohort of Australian women and identifies advanced age, prior low trauma fracture, a history of falls and increased bone turnover as potential key predictors.