Appendicectomy, childhood hygiene, Helicobacterpylori status, and risk of inflammatory bowel disease: a casecontrol study

Aims—To examine the relation between inflammatorybowel disease and appendicectomy, childhood domestic hygiene, andHelicobacter pylori infection.
Methods—Case control study involving 213 patientswith ulcerative colitis, 110 with Crohn's disease, and 337 controlshaving elective surgery.
Results—Nine patients with ulcerative colitis(4.5%) reported a previous appendicectomy compared with 57 controls(19%) (odds ratio (OR) 0.20, 95% confidence interval (CI) 0.1-0.4,p<0.0001). The inverse association was unaffected by excludingoperations performed after the age of onset of ulcerative colitis andwas stronger for appendicectomy performed before age 20 (OR 0.14). Noassociation with appendicectomy was found for Crohn's disease and noassociations with tonsillectomy for either disease. The availability ofa fixed hot water supply in early childhood (before age 11) wasassociated with Crohn's disease (OR for hot water not always versusalways available 0.56, 95% CI 0.3-0.9, p=0.02) but not withulcerative colitis. No other aspect of domestic hygiene before or afterage 11 was associated with either Crohn's disease or ulcerativecolitis. Although H pylori seroprevalence was positively associated with overcrowding (p<0.001) and the absence of running hotwater in childhood it was not associated with the presence of eitherCrohn's disease or ulcerative colitis. H pyloriseroprevalence was no lower in patients who had been exposed tosulphasalazine than in controls or those not exposed.
Conclusions—Our findings confirm the stronginverse association between previous appendicectomy and the developmentof ulcerative colitis and suggest that the protective effect is greaterfor appendicectomy performed in childhood.

Keywords:inflammatory bowel disease; appendicectomy; tonsillectomy; childhood hygiene; Helicobacter pylori; sulphasalazine