The prevalence and incidence of vertebral fractures in an elderly population - The AGES-Reykjavik Study

Abstract

Introduction: Osteoporotic fractures are a major health threat as 1 in 3 women and 1 in 5 men over the age of 50 will experience an osteoporotic fracture in their remaining lifetime. Vertebral fractures are the most common fractures in patient with osteoporosis and may cause acute or chronic pain and reduce the quality of life. Study aim: The aim of this study was to estimate prevalence and incidence of vertebral fractures in 3172 participants from the Age Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik Study) and the assocation of risk factors with prevalence and incidence of vertebral fractures was estimated. Methods: The participants underwent computed tomography examination of the lumbar spine and a part of thoracal spine two times with 5 years apart and these examinations were measured to evaluate prevalence and incidence of vertebral fractures. The average age of the participants were 76 ± 6 years, 58% women and 42% men. Baseline risk factors assessed in relation with prevalent and incident vertebral fractures included age, sex, bone mineral density, bone-promoting medication use, body mass index, history of previous major osteoporotic fractures, family history of osteoporosis, smoking and alcohol use.In this study, a computer program (Spine Analyzer, Optasia Medical, Cheadle, UK) was used to evaluate the shape of the vertebrae and detect a vertebral fracture. This program is based on the semi-quantitative Genant method for classifying vertebral fractures based on the vertebral body shape and severity of fractures.Results: Prevalence was found to be 17.4% in women and 16.2% in men and the fracture incidence was found to be 10.0% in women and 8.3% in men. Women were not at statistically significantly higher risk than men of prevalent or incident vertebral fractures. Both prevalence and incidence of vertebral fractures increased significantly with increasing age and in addition, low bone mineral density, a history of major osteoporotic fracture and a prevalent vertebral fracture were a significant risk factors of prevalent and incident vertebral fractures. The results were similar when mild deformities were removed from the analysis and combined with normal vertebrae for enhancing the fracture cases group but additionally, after enhancing the fracture cases group, women were at statistically significantly higher risk of having prevalent and incident vertebral fractures compared with men (OR = 1.30, 95%CI, 1.02 – 1.67 for prevalence and OR = 1.32, 95%CI, 1.01 – 1.73 for incidence). This higher age-adjusted risk of incident vertebral fractures in women compared with men did not remain significant after additionally adjusting for bone mineral density.Conclusion: The prevalence of vertebral fractures in Icelanders was comparable to the prevalence in populations in extant studies. The incidence of vertebral fractures was also similar in this study compared with other studies. However, the sex difference in incidence between men and women in other population-based studies was greater compared with the difference between the sexes in this study. The sex difference might be explained by a greater difference in BMD between men and women in populations in extant studies compared to the population in this study. Age, low bone mineral density and previous osteoporotic fractures were risk factors that significantly increased the risk of prevalence and incidence of vertebral fractures in the elderly. After excluded the mild deformation from the analysis it was shown that sex had significant association on fracture risk where women were in higher risk of having prevalent and incident vertebral fractures compared with men, suggesting that before the exclusive of mild 1 deformities the fracture risk was probably underestimated in men. The results of this study have give an insight in risk factors and understanding of osteoporosis and osteoporotic vertebral fractures and can be important for future studies. This study reveals important factors linked to osteoporosis and osteoporotic fractures and contributes knowledge since there is not much information about osteoporotic fractures in elderly Icelanders.