Association between obesity and biomarkers of inflammation and metabolism with cancer mortality in a prospective cohort study.

OBJECTIVE: To investigate the association between biomarkers of inflammation and metabolic dysregulation and cancer mortality by obesity status. METHODS: Data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort was used to examine the associations between baseline biomarkers of inflammation (IL-6, IL-8, IL-10, and CRP) and metabolism (adiponectin, resisting and lipoprotein (a)) with cancer mortality among 1822 participants cancer-free at baseline. Weighted Cox proportional hazard regression with the robust sandwich method was used to estimate the hazard ratios and 95% confidence intervals (CIs) adjusting for baseline covariates and stratified by BMI (normal, overweight/obese) given the significant interaction between biomarkers and BMI (p < 0.1). RESULTS: During a mean follow-up of 8 years, there were statistically significant associations between cancer mortality and being in the highest vs. lowest tertile of IL-6 (HR: 5.3; 95% CI: 1.6, 17.8), CRP (HR: 3.4; 95% CI: 1.0, 11.2) and resistin (HR: 3.7; 95% CI: 1.2, 11.2) among participants with normal BMI. IL-6 was also associated with a 3-fold (HR: 3.5; 95% CI: 1.5, 8.1) increased risk of cancer mortality among participants with overweight/obesity; however, neither CRP nor resistin was significantly associated with cancer mortality in this group. CONCLUSIONS: Higher baseline inflammatory and metabolic biomarkers were associated with significantly increased risk of cancer mortality after adjusting for baseline risk factors and the associations varied by BMI. Cancer patients may benefit from interventions that modulate inflammatory and metabolic biomarkers.