Alcohol intake is associated with a decreased risk of developing primary biliary cholangitis

BACKGROUND: Primary biliary cholangitis (PBC) is a chronic progressive liver disease of unknown aetiology characterised by immune-mediated destruction of small and medium-sized intrahepatic bile ducts. There are few well-established risk factors and epidemiological studies are needed to further evaluate the pathogenesis of the disease. AIM: To evaluate the relationship between alcohol intake, smoking and marijuana use with PBC development. METHODS: We conducted a prevalent case control study of 200 cases and 200 age (within a five year age band) and sex-matched controls, identified from the Victorian PBC prevalence study. We assessed lifetime alcohol intake and smoking behaviour (both tobacco and marijuana) prior to PBC onset and used conditional logistic regression for analyses. RESULTS: Alcohol intake consistently showed a dose-dependent inverse association with case status, and this was most substantial for 21-30 years and 31-40 years (P(trend )< 0.001). Smoking was associated with PBC, with a stronger association with a longer duration of smoking [e.g., adjusted OR 2.27 (95%CI: 1.12- 4.62) for those who had smoked for 20-35 years]. There was no association between marijuana use and PBC. CONCLUSION: Alcohol appears to have an inverse relationship with PBC. Smoking has been confirmed as an environmental risk factor for PBC. There was no association between marijuana use and PBC.