Prevalence and predictors of bone mineral density in inflammatory bowel disease

ABSTRACT

Osteoporosis is established in inflammatory bowel disease [IBD] but the mechanisms underlying this disorder has not been well defined. The aim of this study was to assess bone mineral density [BMD] in inflammatory bowel disease [IBD] and evaluate any potential differences between crohn s disease [CD] and ulcerative colitis [UC]. Also we will try to define biochemical markers that predict the changes in BMD. Twenty six patients with recently diagnosed [3-6 months] crohn s disease [9 patients] and ulcerative colitis [17 patients] and 15 age and gender matched healthy controls were enrolled in the study. IBD is diagnosed on clinical, radiological and colonoscopic basis. BMD of lumbar spines, femur and radius were assessed using dual energy x-ray absorptiometry within 3 months after establishing the diagnosis. Laboratory work included serum calcium, phosphate, alkaline phosphatase and free osteocalcin. Results showed that, BMD is significantly decreased in IBD in comparison to control group [P- value <0.001], with femur more affected than vertebra [P<0.05]. BMD is more affected in CD patients than those with UC 65% [CD]. 55% [UC] ate osteopenic and 35% [CD], 17% [UC] are osteoporotic. In CD femur T-score shows significant inverse correlation to the-disease duration [r= - 0.72] and in UC patients spine T- score is inversely related to the age [r= - 0.58] and femur T-score is significantly related to sex [more negative in males]. Serum calcium, phosphorous and alkaline phosphatase are not associated with significant difference between patients and control group [P<0.05] and there is an inverse correlation between osteocalcin and lumbar spine BMD [r=0.37, P<0.05]. In conclusion, IBD patients have significant lower BMD value and BMD is more affected in CD patients than those with UC. Osteopenia is related to disease duration in CD, while it is related to age and male sex in UC. Free osteocalcin is an independent risk factor for low BMD of lumbar spines