Objectively measured physical activity and inflammatory cytokine levels in middle-aged Japanese people

Objective: Studies using self-reported physical activity (PA) showed that higher PA is associated with lower circulating levels of C-reactive protein; in contrast, studies investigating associations of objective PA and other inflammatory markers are limited. We investigated cross-sectional associations of accelerometer-determined PA with circulating levels of myokine-type inflammatory cytokines in a middle-aged Japanese population. Method: A total of 1838 individuals (737 men and 1101 women) aged 40 to 69 years participated in the baseline survey of a population-based cohort study in Saga, Japan (2005-2007). Habitual PA was assessed by a single-axis accelerometer. Serum interleukin (IL)-4, IL-6, IL-8, IL-15, and tumor necrosis factor (TNF)-alpha were measured by a multiplex enzyme-linked immunosorbent assay. Associations between PA and cytokine levels were assessed by multiple regression analysis and analysis of covariance, with adjustment for potential confounders. Results: Step count and PA level (PAL) were inversely associated with TNF-alpha. and IL-15 even after adjusting for BMI. Similarly, greater PA indices were also independently associated with a lower level of inflammatory cytokine z score as an index of overall inflammation. Conclusion: The current results suggest that greater engagement in daily PA may be linked with reduced levels of myokine-type cytokines including IL-15, irrespective of body weight in middle-aged Japanese people. (C) 2014 Elsevier Inc All rights reserved.