Crohn’s disease is an inflammatory gastrointestinal disease, believed to be caused by a combination of environmental, immune, and bacterial factors. It can lead to abscesses and abnormal connections between the intestines (fistulas) and other areas of the body, which often require surgery.
In both France and the USA, there is a higher incidence of Crohn’s disease in the northern parts of the country compared to the southern parts. Because areas closer to the equator experience greater amounts of sunlight and UVB radiation, the major determinant of vitamin D status, it is hypothesized that these north-south disparities in Crohn’s are due to differences in vitamin D status.
Additionally, both prevalence and disease activity of Crohn’s has been negatively associated with vitamin D levels.