Bone density reduction in patients with Crohn disease and associations with demographic and disease variables: cross-sectional data from a population-based study.

BACKGROUND: The extent of bone density reduction in patients with Crohn disease is still being debated. The aim of this study was to examine bone mineral density (BMD) and factors associated with reduced BMD in a representative population of patients with Crohn disease aged between 20 and 70 years.
METHODS: BMD (using dual energy X-ray absorptiometry) was measured in spine and hip in 55 patients with Crohn disease recruited from the entire Crohn population (n = 96) in a defined area of southern Norway. Demographic and clinical data were also collected. The patients were compared with 52 age- and gender-matched healthy controls. Potential demographic and disease-related factors associated with BMD reduction were statistically tested with bi- and multivariate analyses.
RESULTS: The BMD reduction in patients with Crohn disease was 7.1% (P = 0.02) in spine L1-4, 6.1% (P = 0.08) in femoral neck and 8.4% (P = 0.02) in total hip as compared with the controls. In total hip and femoral neck, age, body weight and gender were independently associated with reduced BMD, but in the spine only body weight. Among the disease-related variables, only ever use of prednisolone was independently associated with reduction in BMD but this only in the femoral neck.
CONCLUSIONS: The spine and hip BMD reduction of 6%-8% is similar to that found in a comparable population-based study performed in another area in Norway. Among the disease-related variables tested for, only the use of prednisolone was independently associated with BMD reduction. However, the BMD reduction measured in this study indicates that disease-related mechanisms are involved.