Assessment of bone health by bone turnover biomarkers in a cohort of Egyptian patients with inflammatory bowel disease: a cross-sectional analytical study

Abstract

Background
Patients with inflammatory bowel disease (IBD) are at variable risk of reduced bone mineral density (BMD) and osteoporosis (OP) owing to glucocorticoids, chronic inflammation, malabsorption, etc. This makes them prone to osteoporotic fractures, which poorly affect the quality of life. Our purpose is to measure bone turnover markers (BTMs) reflecting bone resorption and formation, in addition to calciotropic hormones in IBD patients, and compare them to healthy controls and their relation to disease activity, extension, and treatment modalities.


Results
This is a cross-sectional analytical study that included 92 participants: 45 IBD patients; ulcerative colitis (UC) and Crohn’s disease (CD) and 47 controls. Fasting blood samples were withdrawn for BTMs including bone formation markers (Procollagen I N-terminal propeptide {PINP} and bone-specific alkaline phosphatase {BALP}) and bone resorptive marker (C-terminal telopeptide of type I collagen {CTX}) in addition to calciotropic hormones (25-hydroxyvitamin D {25(OH)D} and parathyroid hormones PTH}). These markers were evaluated in both UC and CD patients with respect to disease activity, extension, or treatment modality.
Low serum 25(OH)D levels were detected in UC (92%) and CD (100%), whereas high PTH levels were detected in UC (48%) and CD (45%) with elevated median levels. No significant differences were identified between the UC and CD groups.
IBD patients exhibited a significant increase in CTX, PINP, and BALP levels, indicating higher turnover and metabolic bone disease with no significant differences between UC and CD groups. Higher levels of BTMs were observed in cases with low vitamin D levels. Considering disease activity and bowel involvement, BTM levels were comparable in UC and CD patients. Patients receiving anti-tumor necrosis-α (anti-TNF-α), 17/45, had significantly lower increases in CTX and PINP levels.


Conclusion
Biochemical and hormonal work-up using BTMs, 25(OH)D, and PTH may be beneficial to assess early bone health in IBD patients. IBD patients with lower levels of vitamin D were more prone to higher BTMs and bone changes. However, IBD patients receiving anti-TNF-α were less prone to bone changes, denoting better bone integrity, than those not receiving anti-TNF-α.