Inflammation on the Frontlines: Linking Salivary and Blood Biomarkers to Cardiometabolic Health and Physical Performance Parameters in Firefighters

Objective: Firefighters experience chronic stress that contributes to elevated cardiometabolic disease (CMD) risk. This study examined associations between blood and salivary biomarkers of inflammation, stress, and oxidative stress with measures of body composition, fitness, and cardiometabolic health among firefighters (n = 140). Methods: Principal components analysis was used to reduce multicollinearity among body composition, physical performance, and cardiometabolic variables, followed by multivariate regression models predicting adiponectin, C-reactive protein (CRP), and interleukin-6 (IL-6) concentrations. Results: Body mass and composition, fitness, and atherogenic dyslipidemia were associated with multiple biomarkers. Salivary IL-6 demonstrated robust associations with body composition, physical performance, and salivary CRP. Blood adiponectin and CRP were strongly associated with atherogenic dyslipidemia, insulin resistance and oxidative stress. Conclusions: Salivary inflammatory biomarkers, particularly IL-6, may provide a feasible complement to blood biomarkers for identifying CMD risk among firefighters.