Introduction
Patients with inflammatory bowel disease (IBD) are at increased risk of reduced bone mineral density (BMD), often linked to chronic inflammation, corticosteroid use, biologics, and vitamin D deficiency. 25-hydroxyvitamin D (25(OH)D) is a fat-soluble vitamin essential for calcium and phosphorus homeostasis, and its deficiency is common in IBD due to malabsorption, dietary, altered metabolism, or impaired VDR signaling.
Aims & Methods
This cross-sectional study aimed to evaluate the relationship between serum 25(OH)D levels, BMD, and body composition in IBD patients. A total of 73 outpatients with IBD (38 ulcerative colitis, 35 Crohn’s disease) were assessed. Body composition was evaluated using BMI and bioelectrical impedance analysis (BIA). BMD was measured using whole-body dual-energy X-ray absorptiometry (DEXA), and vitamin D status was assessed by serum 25(OH)D concentration. Statistical analysis included descriptive and comparative tests (Chi-square and t-test).
Results
Participants had a mean age of 45.27±11.37 years, with 67.1% being female and a mean disease duration of 10.22±7.54 years. Most patients (93.15%) were in clinical and endoscopic remission. The average BMI was 26.85±4.51 kg/m², with 39.7% classified as overweight. DEXA revealed a high prevalence of osteopenia (39.7%) and osteoporosis (19.0%). Mean BMD Z-scores were whole body -1.32±1.13, spine -0.92±1.19, and femoral neck -0.34±1.02. Mean serum 25(OH)D level was 31.20±8.78 ng/mL; 52.1% had insufficient levels and 47.9% were sufficient. Vitamin D insufficiency was significantly associated with osteopenia/osteoporosis (p=0.0144) and with overweight/obesity (p=0.0265). No significant associations were observed between vitamin D levels and age (p=0.6476), sex (p=0.4565), lean mass (p=0.2941), fat mass (p=0.1218), phase angle (p=0.3154), or regional BMD (total body p=0.5001; spine p=0.3067; femoral neck p=0.2364).
Conclusion
IBD patients are vulnerable to low serum vitamin D levels and present a high prevalence of low BMD. Vitamin D insufficiency was associated with altered BMI and increased risk of osteopenia/osteoporosis, though not with other body composition metrics. Further studies are needed with larger and more clinically heterogeneous samples to confirm these associations and guide screening and supplementation strategies.
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