ObjectiveTo explore the association between intake of pickled vegetables and colorectal cancer (CRC), including the interactions between pickled vegetables and other dietary habits. MethodsA 1∶1 matched case-control study was undertaken, involving 400 patients with newly histopathologically diagnosed CRC and 400 healthy residents matched by age and gender. The participants were asked to complete a questionnaire. Conditional logistic regression models were established to identify risk factors of CRC and interactions between these factors. Additive interactions were analyzed using relative excess risk of interaction (RERI), attributable proportion of interaction (AP), and synergy index (S). ResultsExcessive intake of pickled vegetables (more than 3 times per week) increased the risk of CRC 〔odds ratio (OR)=2.703, 95% confidence interval (CI): 1.866-3.916〕. There was no multiplicative interaction between pickled vegetables and other dietary habits. Additive interactions were detected between pickled vegetables and cured meat, tea and bean products: with a RERI of 3.172 (95%CI: 0.834-5.518), 2.131 (95%CI: 0.115-4.417) and 2.503 (95%CI: 0.760-4.246), respectively; an AP of 0.472 (95%CI: 0.245-0.699), 0.386 (95%CI: 0.122-0.650) and 0.493 (95%CI: 0.253-0.732), respectively; and a S of 2.244 (95%CI: 1.266-3.978), 1.893（95%CI: 1.050-3.416）and 2.586 （95%CI：1.168-5.723）, respectively. ConclusionExcessive intake of pickled vegetables may be a risk factor of CRC. Cured meats and pickled vegetables might have a synergistic effect on CRC. However, tea and bean products might be antagonistic to the risk imposed by pickled vegetables on CRC.
