Important predictors in the final model included smoking, symptoms (diarrhea, rectal bleeding, change in bowel habit, and mucus per rectum), extraintestinal manifestations (dermatological, ophthalmic, and primary sclerosing cholangitis), coexisting conditions (IBS and hemorrhoids), family history of IBD, appendicectomy, loperamide prescription, anemia (low Hb, MCV, and ferritin), low albumin, and raised inflammatory markers (CRP, ESR, and platelets). This evidence concerns the gene GSTM1 and inflammatory bowel disease.