By Deanna M Green, PhD
11/28/2003
Osteopenia is highly prevalent in patients with Crohn's disease, particularly those who have the disease for longest duration, but is not due to steroid use, according to a Canadian study.
Crohn's disease is associated with a number of musculoskeletal complications. However, the precise nature and incidence of these events is still unknown. Osteoporosis occurs in 30% to 50% of patients with Crohn's disease and the pathogenesis is thought to be multifactorial.
Previously, researchers proposed that corticosteroid therapy and prolonged chronic inflammation affect the risk of osteoporosis.
To determine whether patients with Crohn's disease ultimately become osteopenic and how steroid use and disease duration are related to bone loss, Elias Thodis, MD, University Health Sciences, Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada, and colleagues evaluated the relationship between steroid dose, duration of disease and development of osteopenia in patients with Crohn's disease.
Their cross-sectional, retrospective study included 11 women and 17 men with a mean age of 40.7 years who were diagnosed with Crohn's disease. Notably, all but two patients were in clinical remission. The researchers assessed patients' bone mineral density and levels of several bone-related factors and analysed these measurements with respect to cumulative steroid dose. The mean standardised dose in this cohort was 17.2 g of prednisone.
Osteopenia of the spine was detected in 19 patients. More specifically, 12 had a z-score between -1 and 1.5, and four had a z-score between -1.5 and -2.5.
A severe decrease in bone density of the spine (z-score < -2.5) was observed in five patients. there also were significant effects in the hip, with 10 patients having a z-score below -2.5.
Men had significantly lower lumbar spine and femoral neck z-scores than women. The researchers also found that disease duration had a significant effect on z-scores. Patients who had Crohn's disease more than 2 years also had a significantly lower lumbar spine and femoral neck z-scores than those with shorter disease duration.
No correlation was found between cumulative steroid dose and bone density or steroid dose and biochemical markers of bone turnover. Steroid dose was not associated with a risk of vertebral fracture.
The researchers conclude from this study that "patients with Crohn's disease have a reduced bone mineral density, which is due not simply to steroids, but is significantly correlated with disease duration." He also adds that "the chronic inflammatory process and the nature of the disease itself are important with respect to loss of bone mineral density and need further exploration. "
J Musculoskel Neuronal Interactions 2003;3:3:246-250. "Negative impact of Crohn's disease on bone mineral mass" PDF available here.