Prevalence of appendectomy among ulcerative colitis patients and their relatives

Background It has been suggested that appendectomy may protect against ulce rative colitis (UC). However, the incidences of appendectomy and UC in deve loped countries have diverged over the last 50 years, possibly as a consequ ence of environmental factors. Aim To determine whether the incidence of appendectomy is lower in patients with UC than in the general population. Methods Patients with UC (153), their relatives (116) and members of the ge neral population (306) that had been matched for age, sex and educational s tatus were studied. Results Six per cent of UC patients had undergone appendectomy. The corresp onding figure for non-family controls was 20% (P < 0.0001; OR = 0.27; 95% C I = 0.15-0.45). The rate of appendectomy within families (cases plus siblin gs) was 17/269 (6.3%) and was similar to that for UC patients alone(P < 0.0 01). Conclusions A negative association betweenappendectomy and UC exists in our patients with UC. In addition, the appendectomy rate in families of UC pat ients was lower than that in the general population, possibly implying that common environmental and genetic factors could play an important role in t he divergent incidences of appendicitis and UC over the last 50 years. Eur J Gastroenterol Hepatol 13:1231-1233 (C) 2001 Lippincott Williams & Wilkins .