Occupation and risk of cholangiocarcinoma in the CARA case-control study

Abstract Introduction The association between cholangiocarcinoma (CC) and occupational exposure to asbestos and chlorinated solvents has been studied. This study aims to evaluate whether there is an increased risk of CC in specific occupational categories. Methods Case and control subjects of the CARA (Cholangiocarcinoma Aetiology: Role of Asbestos) study were grouped in occupational categories according to ISCO-88 classification. We fitted multivariate logistic regression models to estimate Odds Ratios (OR) and 95% confidence intervals (CI) adjusting for gender, age, comorbidities, smoking habits, and familiarity. Subgroup analyses were performed among idiopathic subjects. The reference category comprised administrative clerks and other white-collar workers. Result We found an increased risk for CC in “agricultural workers” (OR 3.4, 95%CI 1.2-9.1) and “typographers/painters” (OR 5.1, 95%CI 0.9-27.7). The risk for “sales workers” and “service sector workers” was 0.5 (95%CI 0.3-0.9) and 0.3 (95%CI 0.1-0.9), respectively. Among subjects without comorbidities, the risk for CC was increased for “construction workers” (OR 4.9, 95%CI 1.2-20.0). Discussion Occupational exposure to asbestos is common among agricultural and construction workers, while typographers/painters are likely to be exposed to solvents. The absence of occupational exposure to risk factors along with the role of socioeconomic conditions could help explaining the reduction of risk for CC in some occupational categories. Conclusion Our results supported the association between asbestos and solvents and the risk of CC. Further studies are needed to reinforce the hypothesis of the association between occupational (and non-occupational) risk factors for CC.