Low Bone Mineral Density in Young Patients Newly Diagnosed with Inflammatory Bowel Disease

Background The prevalence and risk factors of low bone mineral density (BMD) in Asian patients newly diagnosed with inflammatory bowel disease (IBD) have not been fully suggested. Aims We aimed to examine the prevalence and risk factors of low BMD in young Korean patients newly diagnosed with IBD. Methods We prospectively enrolled 132 patients aged less than 50 years and newly diagnosed with IBD from six tertiary referral centers in Korea between November 2014 and April 2017. BMD was measured by dual-energy X-ray absorptiometry, and then the Z-score was determined. We defined low BMD as a Z-score <= - 1.0. Results Of 68 patients with ulcerative colitis (UC), 22 (32.4%) had low BMD. Also, of 64 patients with Crohn's disease (CD), 24 (37.5%) showed low BMD. Results from multivariate regression analysis identified the risk factors for low BMD as a high level of alkaline phosphatase (ALP) (>= 140 U/L) (P = 0.010) in UC patients, and being underweight (body mass index <= 18.5 kg/m(2)) (P = 0.017) in CD patients. Conclusions Our study showed that about one-third of newly diagnosed IBD Asian patients had low BMD. The clinical factors associated with low BMD were a high level of ALP in UC patients, and being underweight, in CD patients. Therefore, measurements of BMD in young patients should be considered at the diagnosis of IBD.