"Overall, Jess and colleagues found an increased risk of developing inflammatory bowel disease for women who had endometriosis as demonstrated by a standardized incidence ratio of 1.5. This amounts to a 50% increase in the risk for inflammatory bowel disease among this patient population. The researchers found standardized incidence ratios of 1.5 and 1.6 for ulcerative colitis and Crohn’s disease, respectively. When Jess and colleagues limited analysis to those women whose diagnoses of endometriosis were verified via surgery, the association between endometriosis and ulcerative colitis and Crohn’s disease increased, with standardized incidence ratios climbing to 1.8 and 1.7, respectively. On average, women with endometriosis developed inflammatory disease about 10 years after their endometriosis diagnosis."
http://hcp.obgyn.net/endometriosis/content/article/1760982/2012566