I've blogged about this before, but there was a recent study that revealed that people who live in sunnier regions of the United States are less likely to develop IBD. It confirms previous research conducted in Europe that generated the similar results. The study followed over 200k participants that began the study without symptoms of IBD."A leading explanation for this north-south gradient in the risk of ulcerative colitis and Crohn's disease may be differences in exposure to sunlight, or UVB radiation, which is generally greater in southern latitudes," wrote Dr. Hamed Khalili, of Massachusetts General Hospital in Boston, and colleagues.
"UV radiation is the greatest environmental determinant of plasma vitamin D, and there is substantial experimental data supporting a role for vitamin D in the innate immunity and regulation of inflammatory response," they noted.



