Relationships between markers of inflammation and muscle mass, strength and function: findings from the Hertfordshire Cohort Study

PurposeTo investigate the longitudinal relationships between inflammation markers and the following outcomes in a UK cohort study: appendicular lean mass (ALM); walking speed; level and change in grip strength; and sarcopenia defined by the European Working Group on Sarcopenia in Older People.MethodsAnalyses were based on 336 community-dwelling older men and women (aged 59 to 70 years) who participated in the Hertfordshire Cohort Study (HCS). Inflammation markers were ascertained at baseline using enzyme-linked immunosorbent assay (ELISA) techniques and Bio-Plex Pro Assays. Grip strength was measured at baseline and follow-up (median follow-up time: 10.8 years [inter-quartile range 10.2 to 11.6]) and change in grip strength was ascertained using a residual change approach. At follow-up, ALM was ascertained using dual-energy X-ray absorptiometry (DXA), customary walking speed was measured and sarcopenia status was ascertained. Gender-adjusted linear and Poisson regression was used to examine the associations between inflammation markers and outcomes with and without adjustment for anthropometric and lifestyle factors. Results Higher C-reactive protein (CRP) was associated (p<0.04) with lower grip strength and accelerated decline in grip strength from baseline to follow-up. Higher cortisol was associated with lower ALM (p<0.05). Higher interleukin-8 (IL-8) was associated with lower ALM (p<0.05) and increased risk of sarcopenia (fully-adjusted relative risk per SD increase in IL-8: 1.37 [95%CI:1.10,1.71], p=0.005). All associations were robust in fully-adjusted analyses.ConclusionsInflammation markers were associated with measures of muscle mass, strength and function in HCS. Further work is required to replicate these associations and to delineate the underlying mechanisms.