Sex differences in the relationship between obesity, C-reactive protein, physical activity, depression, sleep quality and fatigue in older adults.

Fatigue is a serious health concern in the elderly. Sex differences exist in adiposity, systemic inflammation, physical activity/fitness and fatigue; however, the relations among these variables remain inadequately characterized impeding the development of fatigue prevention strategies. Measures of adiposity, C-reactive protein, physical activity, aerobic fitness, fatigue, sleep quality and depression were obtained from 127 community-dwelling older adults. Although similar in age (70 y) and BMI (28.0kg/m(2)) women (n=80) reported 63% greater fatigue than men (p=0.04). Adiposity (r=0.44), CRP (r=0.29), physical activity (r=-0.26) and fitness (r=-0.41) were related to fatigue in women (all p<0.05), but not in men. Depression was also related to fatigue in women (r=0.37), and was the only variable related to fatigue in men (r=0.42). In women, fatigue was independently explained (all p<0.05) by CRP (6.6%), depression (6.3%), physical activity (5.8%), and adiposity (3.9%); however, in men, only depression explained variance in fatigue (12.0%). CRP was 40% higher and adiposity 12% higher in women reporting fatigue compared to those with no fatigue; no such differences existed in men. Obese women perceived a greater degree of fatigue than non-obese women, but this was not the case in men. Women report more fatigue than men which was independently associated with inflammation, depression, physical activity and adiposity, whereas in men the only independent predictor was depression. Strategies to prevent fatigue may differ in older women and men, especially with regard to inflammation, physical activity and adiposity.