Associations of Circulating Inflammatory Biomarkers with Risk Factors for Colorectal Cancer in Colorectal Adenoma Patients

Obesity and central adiposity are associated with colorectal cancer risk and have been linked to inflammation. Inflammation is a complex, interactive response that may most accurately be summarized through multiple, simultaneously measured cytokines. In this cross-sectional analysis, we investigated associations of circulating plasma levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-1β (IL-1β), and a combined inflammation z score with risk factors for colorectal cancer in colorectal adenoma patients (n = 92). Multivariable logistic regression was used to investigate associations between cytokine levels and known risk factors for colorectal neoplasms. Mean cytokine levels tended to increase with increasing body mass index (BMI), with statistically significant trends in relation to CRP, IL-6, and the combined inflammation z score (P for trend < 0.001, 0.02, and <0.001, respectively). The odds ratios for associations of the inflammation z score with being overweight (BMI 25-29.9 kg/m(2)), obese (BMI ≥ 30 kg/m(2)), or having a high waist-to-hip ratio were 4.33 (95% CI [confidence interval], 1.04-18.00), 5.54 (95% CI, 1.37-22.42), and 4.09 (95% CI, 1.67-9.98), respectively. Our findings support (1) associations of inflammation with increased general and central adiposity and (2) investigation of a combined inflammation score as a risk factor for colorectal neoplasms.