RELATIONSHIP BETWEEN CHRONIC INFLAMMATION AND OBJECTIVELY MEASURED PHYSICAL ACTIVITY IN OLDER ADULTS

• Published in: Innovation in aging 2017-07, Vol.1 (suppl_1), p.898-898
• Main Authors: Knuth, N.D., Caro, S.R., Walter, M., Schrack, J.
• Format: Article
• Language: English
• Subjects: Abstracts
• ISSN: 2399-5300; 2399-5300
• DOI: 10.1093/geroni/igx004.3221

It is well established that physical activity decreases with age, and that lower levels of physical activity contribute to increased risk of functional decline with aging. Aging is also linked with an increased pro-inflammatory state; however, the association between objectively measured physical activity and inflammatory burden in older adults is not well defined. Therefore, physical activity (PA) was measured using wrist-worn ActiGraph Link accelerometers continuously over 7 days in 60 older participants (28 women, aged 69 ± 10 yrs) of the Longitudinal Aging Study at Towson (LAST). Accelerometer data was downloaded in 60-second epochs and expressed as the log-transformed average counts per day across the three axes. Blood samples were collected after an overnight fast, processed, and stored at -80°C until analysis. Plasma interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFa) concentrations were measured by bead-based multiplex assay, and C-reactive protein (CRP) was measured by enzyme-linked immunosorbent assay. Tertiles of each inflammatory factor were created and the association between the mean of the log-transformed activity counts and inflammatory tertiles was modeled using linear regression models, adjusting for age sex, and BMI. In separate models, IL-6 was negatively associated with total daily PA, independent of age (β = -0.11, p = 0.01); however TNFa (β = -0.03, p = 0.49) and CRP (β = -0.06, p = 0.18) were not related to total daily PA. The independent, negative association between IL-6 and total daily PA highlights potential underlying pathways contributing to the age-related decline in PA, and subsequent physical function.