Correlation between low bone density and disease activity in patients with ulcerative colitis

BACKGROUND Different clinical and epidemiological studies using dual-energy X-ray absorptiometry have shown an increased prevalence of low bone mineral density in patients with inflammatory bowel diseases. The aim of this study was to assess the correlation between bone density and the disease activity in patients with ulcerative colitis. METHODS In this cross-sectional study, 52 patients with ulcerative colitis (duration of the disease less than 5 years) were invited to our research center, Golestan province, northeast of Iran, during February 2012 up to August 2012. A demographic checklist and Simple Clinical Colitis Activity Index was completed for each patients and 5 cc of blood sample was taken after obtaining the informed consent. We used colorimetry method for measuring serum calcium, UV method for serum phosphorus and ELISA for serum vitamin D. Dual-energy X-ray absorptiometry was done to evaluate the bone density. Data analysis was done using SPSS software version 16. Normality of data was assessed using Kolmogorov- Smirnov test. T and ANOVA tests were used if data had normal distribution. Mann-Whitney U or Kruskal-Wallis tests were used for the remaining data. Correlation between qualitative variables was evaluated by Chi-square test. RESULTS The mean (±SD) age and disease activity of the patients were 37.72 (±12.18) years and 4.78 (±1.98), respectively. There were no correlation between disease activity and mean age. Low bone density was seen in 30.8%, 11.5%, and 15.4% in spine, femur neck, and hip, respectively. There was no relationship between Z-score of total hip, spine, and femur neck with disease activity, age, and duration of disease (p>0.05). CONCLUSION Our results showed an acceptable rate of low bone density in patients with ulcerative colitis without any correlation with the disease activity index.