Vitamin K status in patients with Crohn's disease and relationship to bone turnover

BACKGROUND: There is a high prevalence of osteopenia among patients with Crohn's disease (CD). There is some evidence that a deficiency of certain bone-active nutrients (including vitamins K and D) may have a partial role in this bone loss. AIMS: To compare the intake and the status of vitamin K in CD patients, currently in remission, with age and sex-matched controls, and furthermore to investigate the relationship between vitamin K status and bone turnover in these patients. SUBJECTS: CD patients (n = 44; mean age: 36.9 yr) and matched controls (n = 44) were recruited from the Cork University Hospital and Cork City area, respectively. METHODS: Bloods were analyzed for the total and undercarboxylated (Glu)-osteocalcin and urine analyzed for cross-linked N-telopeptides of type I collagen (NTx). Vitamin K-1 intake was estimated by food frequency questionnaire. RESULTS: Vitamin K-1 intake in CD patients tended to be lower than that of controls (mean (SD), 117 (82) vs 148 (80) mug/d, respectively; p = 0.059). Glu and NTx concentrations in CD patients were higher than controls (mean (SD), 5.1 (3.1) vs 3.9 (2.1) ng/ml, respectively; p = 0.03 for Glu; and 49 (41) vs 25.8 (19.5) nM BCE/mM creatinine, respectively; p = 0.001 for NTx). In CD patients, Glu was significantly correlated with NTx (r = 0.488; p < 0.001), even after controlling for age, gender, vitamin D status, calcium intake, and corticosteroid use. CONCLUSION: Vitamin K status of CD patients was lower than that of the healthy controls. Furthermore, the rate of bone resorption in the CD was inversely correlated with vitamin K status, suggesting that it might be another etiological factor for CD-related osteopenia.