Demographic, lifestyle, medical and familial factors associated with primary biliary cirrhosis

Background & Aims Primary biliary cirrhosis (PBC) is believed to result from the interaction of genetic and environmental factors. The controlled studies aiming to assess risk factors for PBC are still limited. Our aim was to identify risk factors and co-morbidities associated with PBC in a large monocentric cohort. Methods We enrolled 222 patients with PBC and 509 controls matched for age, gender, and residential location. Standardized questionnaire data, including more than 200 questions regarding demographic and anthropometric features, lifestyle, individual and familial medical history, and reproductive history, were prospectively collected and examined. Risk factors with odds ratio (OR) and confidence intervals (CI) were determined using conditional logistic regression analyses. Results Family history of PBC (OR 6.8, 95% CI 2.8–16.4) or autoimmune thyroid disease (AITD) (OR 7.1, 95% CI 3.5–14.5) in first-degree relatives, and individual history of active or passive smoking (OR 3.1, 95% CI 2.0–5.0), recurrent urinary tract infections (UTI) (OR 2.7; 95% CI 2.0–3.7), AITD (OR 7.7, 95% CI 4.8–12.3), Sjögren syndrome (OR 11.9, 95% CI 5.4–26.3), Raynaud syndrome (OR 7.2, 95% CI 4.3–12.1), pruritus during pregnancy (OR 3.9, 95% CI 2.8–5.3), or abortion (OR 2.0, 95% CI 1.6–2.5) were significantly associated with increased risk of PBC, while use of oral contraceptives (OR 0.6; 95% CI 0.5–0.8) was associated with decreased risk. Conclusion This study confirms some of the previously reported risk factors for PBC, namely family history of disease and individual history of smoking, UTI, and autoimmune conditions, and further identifies the use of oral contraceptives as a putative protective factor.