VITAMIN-D STATUS IN OUTPATIENTS WITH CROHNS-DISEASE

Objective: To assess the prevalence of and risk factors for clinical a nd subclinical vitamin D deficiency in Crohn's disease. Patients: Vita min D status was determined, in winter, in 50 consecutive outpatients with Crohn's disease and in 50 healthy controls. Methods: Vitamin D st atus was determined by measurement of 25-hydroxyvitamin D (25-OH-D), 1 ,25-dihydroxyvitamin D (1,25-(OH)2-D), vitamin-D-binding protein and o f the C-terminal fragment of parathormone in serum, and by calculation of the free 1,25-(OH)2-D index [as a ratio of the molar concentration s of free 1,25-(OH)2-D and vitamin-D-binding protein]. Precise and eva luable dietary records were obtained from 18 patients only. Results: A lthough 56% of patients had low 25-OH-D levels, which correlated (R=-0 .29, P=0.04) with the Crohn's Disease Activity Index (CDAI), there was a trend towards lower 1,25-(OH)2-D levels (P=0.06) in patients with C rohn's disease compared with healthy controls. Serum vitamin-D-binding protein levels were elevated in 56% of patients and, therefore, the c alculated free indices of 1,25-(OH)2-D were decreased in 28%. Parathor mone levels were elevated in one patient only (2%). Vitamin D status w as independent of nutritional status, disease location, and previous i ntestinal resection. Estimated vitamin D intake was low in 11 out of 1 8 patients and had a negative linear correlation with the CDAI (R=-0.5 8, P=0.01). Conclusions: In view of reduced vitamin D intake and frequ ent 25-OH-D deficiency, supplementation is recommended for patients wi th active Crohn's disease, especially during winter. The long-term con sequences of low free 1,25-(OH)2-D levels, as a parameter of subclinic al vitamin D deficiency, on bone metabolism warrants further investiga tion.