Association between serum interleukin-6 and frailty in older men: cross-sectional data.

Abstract

To investigate the association between serum interleukin-6 (IL-6) and frailty. Participants were 581 men aged 60-90yr (median (IQR): 74yr (67-83yr)) from the Geelong Osteoporosis Study. Tallies of ≥ 3, 1-2 and 0 for weight loss/exhaustion/physical-inactivity/slowness/weakness indicated frailty, pre-frailty and robustness, respectively. Anthropometry, lower-limb muscle strength and physical performance were measured and health behaviours self-reported. Serum IL-6 was measured using an enzyme-linked immunosorbent assay and log-transformed (ln-IL-6). Total antioxidant capacity (TAC) was also measured using quantitative colorimetric determination. Multivariable ordinal logistic regression models tested associations between ln-IL-6 and frailty while considering age, anthropometry, comorbidities, TAC, medications that affect inflammatory processes, lifestyle and socioeconomic status. There were 49(8.4%) frail and 315(54.2%) pre-fail men. A relationship was evident between ln-IL-6 and frailty before and after accounting for age (adjusted OR = 1.24, 95%CI 1.01-1.53). Adjusting for medications attenuated the association (OR = 1.20, 95%CI 0.98-1.48). No other confounders were identified. These data suggest that IL-6 is positively associated with frailty in men, partly explained by advancing age and medications known to affect inflammation.