An Increased Serum N-Terminal Telopeptide of Type I Collagen, a Biochemical Marker of Increased Bone Resorption, Is Associated with Infliximab Therapy in Patients with Crohn’s Disease

Background Osteopenia and osteoporosis are considered to be extra-intestinal manifestations of inflammatory bowel disease (IBD). Anti-tumor necrosis factor (TNF)-α biologics have been introduced as novel medications for an active IBD. However, it is still not well documented whether anti-TNF-α affects the frequency of bone loss or abnormality of bone mineral markers among patients with IBD. Aims This study was to investigate the biochemical basis of low bone mineral density (BMD) and increased turnover in IBD during infliximab (IFX) therapy. Methods Forty patients with Crohn’s disease (CD), 80 patients with ulcerative colitis (UC), and 65 age- and gender-matched controls were included. BMD was measured with dual-energy X-ray absorptiometry, and vitamins K and D were measured as serum undercarboxylated osteocalcin (ucOC) and 1,25-(OH) 2 D, respectively. Bone formation and resorption were based on measuring bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx), respectively. Results Significantly lower BMD was found in patients with UC and CD as compared to controls ( P