Elevated serum IL-6 and adiponectin levels are associated with frailty and physical function in Chinese older adults

PURPOSE: Frailty is associated with adverse health outcomes. Its biological markers are essential to enhance diagnostic ease and would contribute to surveillance of the condition. Considering the involvement of pro-inflammatory and nutritional states in frailty, we aimed to investigate whether inflammatory mediators and adipokines are associated with frailty and their relationship with physical function. PATIENTS AND METHODS: We recruited 130 older adults (90 nonfrail participants and 40 frail participants, mean age: 72.80±8.61 years) who underwent a comprehensive medical history and frailty assessment. The biochemical indicators (eg, blood urea nitrogen [BUN], high-density lipoprotein [HDL], and hemoglobin [HGB]), insulin pathway (glucose, insulin, and insulin-like growth factor 1 [IGF-1]), circulating inflammatory biomarkers (IL-6, tumor necrosis factor receptor 1, and C-reactive protein), and adipokines (adiponectin, vaspin, and leptin) were compared between the two groups. We further analyzed their correlation with physical function. RESULTS: Frail older adults showed higher levels of BUN, IL-6, adiponectin, vaspin, and glucose and lower levels of IGF-1, HDL, and HGB compared with nonfrail participants. Serum IL-6 levels were negatively correlated with both grip strength (P=0.03) and gait speed (P=0.04). Levels of circulating adiponectin and leptin were adversely correlated with grip strength (P=0.01) and gait speed (P=0.03), respectively. After adjustment for age and sex, the only markers correlated with physical function were IL-6 (r=−0.180, P=0.044) and adiponectin (r=−0.195, P=0.029). CONCLUSION: High levels of IL-6, adiponectin, vaspin, and glucose as well as low levels of IGF-1 were found in frail older adults. Furthermore, IL-6, adiponectin, and leptin levels were negatively correlated with physical function, suggesting that inflammatory mediators and adipokines are biomarkers for frailty and decreased function in older adults.