Active Crohn's disease is associated with low vitamin D levels

Crohn's disease prevalence increases with increasing latitude. Because most vitamin D comes from sunlight exposure and murine models of intestinal inflammation have demonstrated beneficial effects of 1,25-(OH)2 vitamin D treatment, we hypothesised that Crohn's disease activity is associated with low vitamin D levels. In a cross-sectional study of 182 CD patients and 62 healthy controls, we measured serum 25-OH vitamin D. Stratified analysis was used to compare 25-OH vitamin D levels with Crohn's disease activity index, C-reactive protein, smoking status, intake of oral vitamin D supplements and seasonal variation in CD patients and healthy controls. Serum 25-OH vitamin D was inversely associated with disease activity: Median 25-OH vitamin D levels of Crohn's disease in remission, mildly, and moderately active diseases evaluated by Crohn's disease activity index were 64, 49, and 21nmol/l (p