Investigation Of The Relationship Between Physical Activity, Inflammatory Proteins And Adiponectin In Older Adults

Abstract

INTRODUCTION: Chronic low-grade inflammation (CLGI) is a hallmark of aging and significantly contributes to the development and progression of numerous chronic diseases including cardiovascular disease (CVD) and diabetes. CLGI is frequently defined as elevated serum levels of inflammatory proteins including C-reactive protein (CRP) and interleukin-6 (IL-6). Physical activity has been reported to have anti-inflammatory effects. PURPOSE: To explore the relationships among habitual physical activity, inflammation, and cardiometabolic risk factors in older adults. METHODS: In 82 subjects (23 male / 59 female) body composition was determined (bioelectrical impedance) and physical activity was measured objectively (7-day accelerometry) as well as subjectively (Community Health Activities Model for Seniors (CHAMPS)). Enzyme-Linked Immunosorbent Assays (ELISA) were used for the quantitative measurement of IL-6, CRP, and an anti-inflammatory, adipose tissue derived hormone, adiponectin. Blood lipids were also measured utilizing a point-of-care analyzer. Partial correlations (controlling for age and sex) were used to analyze associations. SUMMARY OF RESULTS: Mean values included: age (68.5 ± 6.3 yr); body fat percentage (31±11%); accelerometry (cts/min: 114.1±56.5, sedentary-to-moderate ratio: 12.8±6.1); CHAMPS (2,328±1658 kcal/wk); CRP (1.5±1.6 mg/dL); IL-6 (4.2±1.0 ng/mL); adiponectin (11.2±6.0 μg/mL); LDL (114±28 mg/dL); and HDL (62±17 mg/dL). CRP was significantly (p< 0.05) correlated with body fat percentage (r= 0.54), HDL/LDL (r= 0.42), IL-6 (r= 0.37), and adiponectin (r= -0.25). IL-6 was significantly correlated with body fat percentage (r= 0.24), activity counts/min (r= -0.27), and LDL/HDL (0.29). Adiponectin was significantly correlated with body fat percentage (r= -0.35), CHAMPS (r= 0.28), and HDL (r= 0.51). CONCLUSION: The average CRP value for this population of older adults is indicative of moderate risk for the development of CVD. The correlations reported here are supportive of previous research suggesting that body composition and physical activity level are important determinants of inflammatory profile and disease risk. This project was funded by an NIH grant 1R15AG055923-01