Epidemiology of vertebral osteoporosis.

Whereas the extent, morbidity and costs of hip and Colles' fracture are well recognised from epidemiological studies, those arising from vertebral fracture are less secure. Reasons relate to the uncertain definition of vertebral fracture and its variable clinical expression, and hence its incidence is not known. Utilising radiological criteria 50% or more of vertebral fractures may be asymptomatic. In the remainder morbidity is significant, particularly in the presence of multiple vertebral fractures. Although the true incidence of vertebral fracture is unknown there is evidence that it increases exponentially with age in much the same way as for hip fracture. Between the ages of 60 and 90 years the apparent incidence rises approximately 20-fold in women compared to a 50-fold increase in risk of hip fracture. The incidence of vertebral osteoporosis is two-fold lower in men than in women at all ages, comparable to the pattern observed with other osteoporotic fractures. However, there is a relatively high incidence of vertebral fracture in men during middle adult-life (probably due to trauma), so that the prevalence of vertebral fracture in the male community is not two-fold less than in women.