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

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.