Vertebral Deformity and Vertebral Fracture in the Elderly

Osteoporosis is a systemic, skeletal disease with the consequence of an increased risk of sustaining a fracture, one of the most common fractures being a vertebral fracture. The lifetime risk of sustaining a clinically diagnosed vertebral fracture from age 50 years onward is 8% in men and 15% in women. These fractures are followed by increased morbidity and mortality as well as an increased risk of sustaining future fragility fractures, a fact that emphasizes the need of preventing the disease.

Individuals with a clinically diagnosed vertebral fracture are, however, only a subset of all individuals with vertebral fractures, revealed if a generalized radiological screening is performed. Furthermore, the changes in the shape of the vertebral body, visible on lateral spine radiographs, do not always represent fractures. As a consequence, changes in the shape of the vertebral body are, in epidemiological studies, referred to as vertebral deformities instead of vertebral fractures.

This thesis evaluates the occurrence as well as the consequences of prevalent vertebral deformities and clinically diagnosed vertebral fractures in Swedish men and women, aged 50 years or more.

In a cross-sectional study the prevalence of vertebral deformity in 343 men and 454 women, age 50-86 years, from two different, population-based cohorts from southwest Sweden, was evaluated using a morphometric method. Thirty-three percent of the men and 39% of the women had vertebral deformities. More women than men had vertebral deformities, and in both genders the prevalence increased with age. The vertebrae most commonly deformed were L1, Th12 and Th11.

The European Vertebral Osteoporosis Study (EVOS) was a multi-centre study evaluating the prevalence of vertebral deformity in 19 European countries. The individuals who were invited but declined to participate in the Malmö part of the EVOS study were analyzed regarding risk factors for vertebral deformities and were compared with age- and gender-matched participants. The “true” prevalence of subjects with vertebral deformity in the whole male Malmö population at risk was probably underestimated in the EVOS study. Whether this is also the case for women was not so clearly indicated.

In the population-based cohort of 298 men and 300 women, age 50-80 years, in the Malmö part of the EVOS study, men and women with a prevalent vertebral deformity had a 2.4- and 2.3-fold, respectively, increased risk of dying during a 10-year follow-up period, compared with individuals without a prevalent vertebral deformity. In men there was an increased mortality due to cardiovascular and pulmonary diseases and in women due to cancer. The presence of a vertebral deformity predicted also future fractures of any type in both genders and future fragility fractures in women.

The prevalence of vertebral deformities among 196 hip fracture patients was higher than among reference subjects from two population-based cohorts. This difference was most pronounced among individuals less than 80 years old. The result suggests that a prevalent vertebral deformity possibly indicates an increased risk of sustaining a hip fracture. There was no difference in the prevalence of vertebral deformity between patients with a per- or subtrochanteric hip fracture and patients with a cervical hip fracture.

Among individuals over 50 years of age, in the Swedish city of Malmö, 1.8 out of 1000 men and 3.6 out of 1000 women sustained a clinically diagnosed vertebral fracture during 1979. Among the women, there were more individuals who, at a follow-up examination 12 years later, had back pain and an impaired health status compared with women from a population-based cohort. Both men and women with a clinically diagnosed vertebral fracture had an increased mortality during the 22 years following the diagnosis compared with the population at risk.