The associations of adiposity, physical activity and inflammation with fatigue in older adults.

Persistent feelings of fatigue are a widespread complaint reported by older adults, and are associated with detriments in health and quality of life. The aim of this study was to determine the influence of weight status, habitual physical activity and inflammation, after controlling for common psychosocial variables such as depression, on perceptions of fatigue in relatively healthy older adults. Older men and women (N=182, age=69.2±6.7 years, 98 men) were assessed for adiposity via dual-energy X-ray absorptiometry, physical activity (PA) using accelerometers, systemic inflammation [serum C-reactive protein (CRP), interleukin-6 (IL-6), sIL-6R and WBC count], fatigue according to the Multidimensional Fatigue Inventory (MFI), sleep using the Pittsburgh Sleep Quality Index (PSQI) and depression via the Geriatric Depression Scale (GDS). Men and women reported similar levels of fatigue in all dimensions (p>0.05) except women reported higher levels of mental fatigue than men (p=0.049). With the exception of mental fatigue, adiposity was positively, and physical activity was inversely associated with all other dimension of fatigue (r range=0.20-0.42, and -0.18 to -0.37, respectively). CRP, IL-6 and WBC were also related to several dimensions of fatigue (r range=0.15-0.26). Regression analyses revealed that after controlling for other factors, including depression and sleep quality, adiposity independently explained a significant amount of the variance in general and physical fatigue. In addition to depression and sleep quality, adiposity may represent a potential target for reducing fatigue in older adults.