a To estimate the prevalence of vertebral osteoporosis in the different regions and populations within Europe and the geographical variation in this prevalence by age and sex.
b To identify and compare within Europe individual risk factors for the aetiology of vertebral osteoporosis with a view to identifying potential strategies for prevention.
c To assess the health and social impact of osteoporosis in the populations studied.
d To assess the feasibility of using data derived from (a) and (b) above to lay the foundations for a subsequent prospective study.
The European Vertebral Osteoporosis Study (EVOS) is a population based study examining the prevalence of, and predictors for, vertebral osteoporosis. 17342 subjects aged 50 years and over were recruited from population based sampling frames in 36 centres in 18 European countries. Equal numbers of men and women were recruited in 6 5-year age bands, 50 to 54, 55 to 59, 60 to 64, 65 to 69, 70 to 74, 75 plus. Each subject completed an interviewer administered questionnaire and had lateral thoracolumbar radiography performed according to a standardized protocol. The X-rays were read morphometrically and the prevalence of fracture derived from these measurements. The average response rate in the participating centres was 48%, though there was wide geographical variation. Reproducibility of the questionnaire information and X-ray measurements was good. Data analysis is still continuing but preliminary results have shown that the prevalence of individual risk factors varied across the participating centres. Using the algorithm for vertebral fracture definition described by Eastell, the prevalence of vertebral fracture varied in those centres where the analysis is complete, by almost 2 fold for grade 2 deformities. The prevalence was highest in Malmo where 29% of females had evidence of significant vertebral deformity (grade 1).
Osteoporosis is a major cause of fracture and gives rise to significant morbidity and mortality particularly in the Western World. Hip fracture is the most widely studied site of fracture, reflecting the significant public health impact associated with it. In contrast to the detailed knowledge concerning hip fracture there are very few data on vertebral fracture. In part this is because vertebral fractures are often asymptomatic and require a radiographic survey to determine prevalence; but also because there is no consensus as to the definition of vertebral fracture. Reported prevalence estimates vary by up to 10 fold and published estimates of the sex ratio vary from a small male excess to a female excess of 7:1. The few data that exist elsewhere have utilised different methods, for assessment, and definition, of vertebral fracture; limiting direct comparison between studies. There is nevertheless increasing awareness that vertebral fracture accounts for significant morbidity in the population.