Daytime somnolence was mediated by tumor necrosis factor-alpha ( mediated 23 % of intervention effect , p < .05 ) , interleukin ( IL ) -6 : IL-10 ( 16 % , p < .01 ) , IL-8 : IL-10 ( 26 % , p < .01 ) , and fatigue ( 38 % , p < .05 ) .