Bratislava Medical Journal Vol.116, No.3, p.148–151, 2016

OBJECTIVES: Vitamin D substitution is recommended in patients with inflammatory bowel disease. Specific guidelines are lacking. The aim of this study was to assess the effect of vitamin D supplementation with respect to dosage and patient compliance.
METHODS: A prospective cohort study of 167 Crohn disease/ulcerative colitis outpatients. Patients were screened for serum vitamin D (25OHD2+3) at the end of summer and in late winter. Demographic data, history of vitamin D supplementation were recorded and matched with prescription records.
RESULTS: A total of 57 subjects used vitamin D supplementation (mean dose 1104 IU/day). 25OHD2+3 levels were lower (p < 0.001) in winter both in substituted and unsubstituted group, without any differences between groups within the same season. 25OHD2+3 levels did not correlate with the substitution dose. 52.1 % of subjects were fully compliant with substitution. 25OHD2+3 and prevalence of vitamin D deficit in this group were comparable with unsubstituted subjects except a higher prevalence of vitamin D insufficiency (p < 0.02).

CONCLUSION: Fixed dosage of 1100 IU/day of vitamin D was insufficient to correct the deficiency. Patient compliance with vitamin D supplementation was low, however this fact did not significantly contribute to the degree of vitamin D deficiency in this dosage (Tab. 3, Fig. 1, Ref. 21).