If living with inflammatory bowel disease (IBD) wasn't hard enough, patients with the digestive disorders Crohn's and colitis may be at an elevated risk for developing skin cancer too, according to research presented at the Digestive Disease Week conference in Orlando.
Researchers at Mayo Clinic discovered the correlation between IBD diagnoses and an eventual diagnosis of melanoma, a very serious form of skin cancer often attributed to sun exposure. An analysis of seven years worth of published studies about IBD uncovered about 180 cases of melanoma diagnosed in 170,000 patients who already had IBD (roughly 90,000 with Crohn's disease and 80,000 with ulcerative colitis). The U.S. Centers for Disease Control and Prevention report that over 60,000 people were diagnosed with melanoma in 2009, of which about 9,000 died.
"Even though we included both population- and clinic-based studies ... which are at minimal risk of selection bias and more generally applicable, the increased risk of melanoma continued to be significant," the researchers write in the review. The Mayo findings suggest that having IBD puts patients at a 37 percent rate of being more likely to develop melanoma. 
The analysis identified only a correlation — an association between two factors that doesn't necessarily prove that one is responsible for the other — between melanoma and IBD, not a causal connection.