Intestinal permeability is increased in a proportion of spouses of patients with Crohn's disease

OBJECTIVE: Increased small intestinal permeability has been found in patien ts with Crohn's disease and in a proportion of their healthy relatives. Thi s may reflect a shared environment or shared genes. The finding of abnormal permeability in the healthy spouses of patients would favor an environment al cause for this observation. METHODS: The healthy spouses of patients with Crohn's disease attending thr ee gastroenterology clinics were invited to participate. Eligible subjects consumed a 350-ml solution containing lactulose, mannitol, and sucrose befo re bedtime. All overnight urine was collected, assayed by high performance liquid chromatography, and the ratio of fractional excretion of lactulose t o mannitol was calculated as an index of permeability. The results were com pared with those of a previously determined control group. RESULTS: Sixty spouses completed the study. Increased permeability was pres ent in eight (13.3%0, 95% Cl = 6.0-24.6%). The presence of increased permea bility was not related to age, gender, duration of cohabitation, alcohol us e, nonsteroidal anti-inflammatory drug use or to disease activity in the pa tient with Crohn's disease. There was a nonsignificant trend for abnormal p ermeability to occur in those spouses cohabiting with the patient with Croh n's disease at the time of disease diagnosis (p = 0.128). CONCLUSIONS: Small intestinal permeability is increased in a proportion of healthy spouses of patients with Crohn's disease. The presence of abnormal permeability studies in patients with Crohn's disease and a proportion of t heir healthy close contacts suggests that this phenomenon is caused by envi ronmental factors. (Am J Gastroenterol 2001; 96:2934-2938. (C) 2001 by Am. Coll. of Gastroenterology).