Risk factors for cholangiocarcinoma in Khon Kaen, Thailand: a nested case-control study.

The present nested case-control study within the Khon Kaen cohort study was conducted to assess risk factors for cholangiocarcinoma (CCA) development. Cases were 108 subjects with proven CCA, by ultrasound at least, and controls also numbered 108, matched by sex, age (not more than 3 years difference) and period of recruitment to the cohort (not more than 3 months difference). A questionnaire was constructed based on that employed for the Khon Kaen cohort study recruitment. McNemar's chi-square test and conditional logistic regression were used for crude analysis and multiple conditional logistic regression for multivariate analysis. Results revealed a sex ratio of 2:1 for males:females. The current study found a statistically significant relationship when adjusted for other potential covariate factors between cholangiocarcinoma and the consumption of total fruits 3-4.6 times per day (OR= 0.32, 95% CI= 0.12-0.88) and history of Opisthorchis viverrini eggs in stools at recruitment plus consumption of meat <0.45 times per day (OR= 2.99, 95% CI= 1.04-8.62). The findings suggest that O. viverrini infestation is the strongest risk factor for development of cholangiocarcinoma and also suggests decrease in risk among individuals who consume more fruit.