Body Mass Index, Physical Activity, and Serum Markers of Inflammation, Immunity, and Insulin Resistance

Background: Epidemiologic studies examining circulating levels of inflammatory markers in relation to obesity and physical inactivity may aid in our understanding of the role of inflammation in obesity-related cancers. However, previous studies on this topic have focused on a limited set of markers. Methods: We evaluated associations between body mass index (BMI) and vigorous physical activity level, based on self-report, and serum levels of 78 inflammation-related markers. Markers were measured using a bead-based multiplex method among 1,703 men and women, ages 55-74 years, and with no prior history of cancer at blood draw, and selected for case-control studies nested within the Prostate, Lung, Ovarian, and Colorectal Cancer Screening Trial. Analyses were adjusted for age, sex, smoking, case-control study, physical activity, and BMI. Results: Twelve markers were positively associated with BMI after FDR correction. ORs and 95% confidence interval (CI) for highest versus lowest levels of CCL2/MCP-1, CXCL5/ENA-78, sTNFRII, CXCL10/IP-10, CXCL6/GCP2, CCL13/MCP-4, amylin, CRP, C-peptide, CCL19/MIP-3b, insulin, and leptin were: 1.50 (1.14-1.98), 1.52 (1.12-2.05), 1.61 (1.17-2.20), 1.69 (1.25-2.28), 1.74 (1.24-2.44), 1.75 (1.22-2.50), 1.91 (1.31-2.78), 2.41 (1.36-4.25), 2.78 (1.83-4.24), 3.30 (2.28-4.78), 4.05 (2.51-6.55), and 50.03 (19.87-125.99) per 5 kg/m(2), respectively. Only CXCL12/SDF-1a was associated with physical activity (>= 3 vs. <1 h/wk; OR, 3.28; 95% CI, 1.55-6.94) after FDR correction. Conclusions: BMI was associated with a wide range of circulating markers involved in the inflammatory response. Impact: This cross-sectional analysis identified serum markers could be considered in future studies aimed at understanding the underlying mechanisms linking inflammation with obesity and obesity-related cancers. (C) 2014 AACR.