Smoking and intestinal absorption of oral polyethylene glycols in Crohn's disease.

Intestinal absorption of orally administered polyethylene glycols with molecular weights of 634-1250 was investigated in 55 patients with Crohn's disease and in 20 healthy controls and was related to smoking habits at the time of testing. In the Crohn patients the polyethylene glycol absorption was also related to smoking habits at the time of diagnosis. Absorption of polyethylene glycols was impaired in Crohn patients compared with controls, but within both groups no difference was found among smokers, ex-smokers, and never-smokers (p > 0.05). Among the Crohn patients, those who smoked at the time of diagnosis had less impaired absorption (p < 0.02) of the smaller polyethylene glycols (634-942 Da) than those who did not. These data do not support the concept of altered intestinal permeability as the mechanism by which smoking influences Crohn's disease.