Plasma inflammatory biomarkers and modifiable lifestyle factors associated with colorectal cancer risk

Background & aims: Chronic inflammation is a leading cause of colorectal cancer (CRC). Inflammatory biomarkers are considered indicators of occult malignancy. To contribute to the investigation of CRC prevention strategies, we aimed to identify associations between inflammatory biomarkers (insulin-like growth factor-1 (IGF-1), soluble tumor necrosis factor receptor 2 (sTNFR-2), and interleukin-8 (IL-8)) and modifiable lifestyle factors including body mass index (BMI), prior BMI, smoking status, alcohol consumption status, physical activity, and dietary inflammatory index (DII) score in terms of CRC risk. Methods: In a hospital-based case–control study, we explored the associations of plasma IGF-1, sTNFR-2, and IL-8 levels with CRC risk in 697 cases and 1845 controls. Unconditional logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for CRC with the inflammatory biomarkers adjusted for confounders. Results: CRC patients had significantly higher levels of sTNFR-2 and IL-8 than the controls (P < 0.001). In multivariate models, the levels of IGF-1, sTNFR-2, and IL-8 were significantly associated with CRC risk after adjusting for confounders (IGF-1 OR (95% CI) = 1.39 (1.02–1.89), P for trend = 0.018; sTNFR-2 = 2.14 (1.59–2.90), P for trend < 0.001; IL-8 = 1.95 (1.43–2.66), P for trend < 0.001, highest vs. lowest quartiles). The biomarkers showed either positive or negative trends when modifiable lifestyle factors were stratified. In particular, the inverse associations of CRC risk with the biomarkers were significant among subjects who engaged in regular physical activity and had an anti-inflammatory diet pattern. Conclusions: Elevated levels of inflammatory biomarkers were associated with CRC risk and could be modified by risk and protective lifestyle factors. Our findings may provide a strategy to identify CRC risk based on the associations between inflammatory biomarkers and lifestyle factors.