Incidence and risk factors for osteoporotic vertebral fracture in low-income community-dwelling elderly: a population-based prospective cohort study in Brazil. The São Paulo Ageing & Health (SPAH) Study.

Abstract

We ascertained the incidence and predictors of radiographic vertebral fracture in a Brazilian elderly cohort, since no data in this field have been reported in low-income countries. This is the first population-based study to demonstrate the high frequency of vertebral fracture in elderly Latin Americans. Age, prior fracture, BMD, and bone turnover were predictors of fracture. Vertebral fractures are associated with increased future fracture risk and mortality. No data on incidence of osteoporotic vertebral fracture have been reported in low-income countries where the population's aging has been faster. Thus, we sought to describe the incidence and risk factors for radiographic vertebral fracture in a longitudinal prospective Brazilian population-based elderly cohort. 707 older adults (449 women and 258 men) were evaluated with spinal radiographs obtained at baseline and after a mean follow-up of 4.3 ± 0.8 years. New vertebral fracture was defined as distinct alteration in the morphology of vertebrae resulting in higher grade of deformity on the second radiograph when compared to the baseline radiograph. Clinical questionnaire, bone mineral density (BMD), and laboratory tests were performed at baseline. Multivariate Poisson regression models were used to identify independent predictors of fracture. The age-standardized incidence of vertebral fracture was 40.3/1,000 person-years in women and 30.6/1,000 in men. In women, three models of risk factors for fracture were fitted: (1) age (relative risks (RR) 2.46, 95 % confidence interval (CI) 1.66-3.65), previous osteoporotic fracture (RR 1.65, 95 % CI 1.00-2.71), and lumbar spine BMD (RR 1.21, 95 % CI 1.03-1.41); (2) age (RR 2.25, 95 % CI 1.52-3.34) and femoral neck BMD (RR 1.42, 95 % CI 1.11-1.81); (3) age (RR 2.11, 95 % CI 1.41-3.15) and total hip BMD (RR 1.56, 95 % CI 1.21-2.0). In men, the highest quartile of cross-linked C-telopeptide (CTx) (RR 1.96, 95 % CI 0.98-3.91) and prior fracture (RR 2.10, 95 % CI 1.00-4.39) were predictors of new vertebral fracture. This is the first population-based study to ascertain the incidence of vertebral fracture in elderly Latin Americans, confirming the high frequency of the disorder. Age, prior fracture, BMD, and bone turnover were predictors of the short-term incidence of vertebral fracture.