Risk factors for metabolic bone disease in Crohn's disease patients.

Background: The aim was to evaluate the presence of metabolic bone disease (MBD) in patients with Crohn's disease (CD) and to identify potential etiologic factors.

Methods: The case-control study included 99 patients with CD and 56 controls with a similar age and gender distribution. Both groups had dual-energy x-ray absorptionmetry and a nutritional evaluation. Single nucleotide polymorphisms at the IL1, TNF-α, LTα, and IL-6 genes were analyzed in patients only. Statistical analysis was performed using SPSS software.

Results: The prevalence of MBD was significantly higher in patients (P = 0.006). CD patients with osteoporosis were older (P < 0.005), small bowel involvement and surgical resections were more frequent (P < 0.005), they more often exhibited a penetrating or stricturing phenotype (P < 0.05), duration of disease over 15 years (P < 0.005), and body mass index (BMI) under 18.5 kg/m(2) (P < 0.01) were more often found. No association was found with steroid use. Patients with a Z-score < -2.0 more frequently had chronic active disease (P < 0.05). With regard to diet, low vitamin K intake was more frequent (P = 0.03) and intake of total, monounsaturated, and polyunsaturated fat was higher in patients with Z-score < -2.0 (P < 0.05). With respect to genetics, carriage of the polymorphic allele for LTα252 A/G was associated with a higher risk of osteoporosis (P = 0.02). Regression analysis showed that age over 40 years, chronic active disease, and previous colonic resections were independently associated with the risk of developing MBD.

Conclusions: The prevalence of MBD was significantly higher in CD patients. Besides the usual risk factors, we observed that factors related to chronic active and long-lasting disease increased the risk of MBD.