The relationship between interleukin-6 levels and physical performance in mobility-limited older adults with chronic low-grade inflammation: the ENRGISE pilot study

Authors: CUSTODERO, CARLO - UNIVERSITY OF FLORIDA; ANTON, STEPHEN - UNIVERSITY OF FLORIDA; BEAVERS, DANIEL - WAKE FOREST SCHOOL OF MEDICINE; MANKOWSKI, ROBERT - UNIVERSITY OF FLORIDA; LEE, STEPHANIE - UNIVERSITY OF FLORIDA; MCDERMOTT, MARY - NORTHWESTERN UNIVERSITY; FIELDING, ROGER - JEAN MAYER HUMAN NUTRITION RESEARCH CENTER ON AGING AT TUFTS UNIVERSITY; NEWMAN, ANNE - UNIVERSITY OF PITTSBURGH; TRACY, RUSSELL - UNIVERSITY OF VERMONT; KRITCHEVSKY, STEPHEN - WAKE FOREST SCHOOL OF MEDICINE; AMBROSIUS, WALTER - WAKE FOREST SCHOOL OF MEDICINE; PAHOR, MARCO - UNIVERSITY OF FLORIDA; MANINI, TODD - UNIVERSITY OF FLORIDA

Submitted to: Archives of Gerontology and Geriatrics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/25/2020
Publication Date: 5/3/2020
Citation: Custodero, C., Anton, S.D., Beavers, D.P., Mankowski, R.T., Lee, S.A., McDermott, M.M., Fielding, R.A., Newman, A.B., Tracy, R.P., Kritchevsky, S.B., Ambrosius, W.T., Pahor, M., Manini, T.M. 2020. The relationship between interleukin-6 levels and physical performance in mobility-limited older adults with chronic low-grade inflammation: the ENRGISE pilot study. Archives of Gerontology and Geriatrics. 90. Article 104131. https://doi.org/10.1016/j.archger.2020.104131.
DOI: https://doi.org/10.1016/j.archger.2020.104131

Interpretive Summary: Previous studies have shown a relationship between low grade inflammation and physical performance such a walking ability in older adults. In the present study we explored the consistency of this relationship in a group of older adults with poor mobility (slow walking speed) and chronic low-grade inflammation. We studied 289 participants (70 years old and over) from the Enabling Reduction of low-Grade Inflammation in Seniors (ENRGISE) Pilot study. We found a significant association between inflammation and lower leg strength (higher inflammation was associated with lower strength (weakness)). We did not find a significant association between inflammation and other measures of physical performance such as walking speed or ability to rise from a chair. These results suggest that the relationship between inflammation and poor physical functioning in older adults is lost in those individuals with both elevated inflammation and mobility limitations. These results have implications for planning and interpreting future research in older adults with low-grade inflammation and mobility limitations.

Technical Abstract: Previous studies have found an inverse relation between serum concentrations of interleukin (IL)-6 and physical performance in seniors, however this was limited to higher functioning older adults with low to moderate levels of inflammation. We explored the consistency of this association in a cohort of mobility limited older adults with chronic low-grade inflammation. This study included 289 participants (>=70 years old) with IL-6 level between 2.5 and 30 pg/mL and a walking speed < 1.0 m/sec from the ENRGISE Pilot study. Physical performance was assessed using the short physical performance battery (SPPB), usual gait speed over 400 m, grip strength, and knee extensor and flexor strength measured by isokinetic dynamometry at 60 and 180 degrees/sec. There was a significant inverse correlation between log IL-6 and knee extensor strength at 60 degrees/sec (r= -0.20, p = 0.002), at 180 degrees/sec (r = -0.14, p = 0.037), and knee flexor strength at 60 degrees/sec (r = -0.15, p = 0.021). After adjustment for potential confounders, the values of knee extensor strength at 60 degrees/sec showed a trend toward a progressive reduction across IL-6 tertiles as IL-6 levels increased (p = 0.024). No significant association was found between IL-6 and other objectively measured physical performance. The findings were generally of smaller magnitude and less consistent than previously reported, which suggests that the associations are attenuated in those with both elevated inflammation and mobility limitations. These results have implications for planning and interpreting future intervention studies in older adults with low-grade inflammation and mobility limitations.