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An epidemiological association between cigarettesmoking and primary biliary cirrhosis (PBC) has been demonstrated. Our aim wasto determine the relationship between smoking and severity of liver fibrosis atpresentation in patients with PBC. All patients with PBC seen at the threemajor teaching hospitals of Case Western Reserve Universitybetween October 1998 and December 2005 were identified. Data obtained at thetime of the first evaluation leading to the PBC diagnosis on 97 patients werecollected. The cumulative number of cigarette packs smoked per year(pack-years) was calculated. Advanced histological disease was defined asLudwig stages 3 or 4. Analyses were performed to determine associations betweenadvanced histological disease, smoking and other variables related to liverfibrosis. Smoking history was more common (P = .0008) in patients with advancedhistological disease at presentation compared to those with early disease.Among smokers, mean lifetime tobacco consumption was higher (P = .04) in caseswith advanced histological disease at presentation (30 pack-years) compared tocases with early disease (17 pack-years). Logistic regression demonstrated asignificant association between a lifetime tobacco consumption of >/=10pack-years and advanced histological disease at presentation (OR = 13.3). Theassociation remained significant after adjusting for age, gender, and alcoholintake. The validity of these results was corroborated by cross-validation inan independent confirmatory set of 172 patients with PBC. In conclusion,smoking may accelerate the progression of PBC. This could be induced byexposure to chemicals in cigarette smoke Leggil'articolo