Elevated leptin and insulin may berelated to day shift work or to workers who have not adapted to theshift. Workers who are poorly adapted to shift work tend to havelower social support and higher levels of stress, depression, andfatigue. Several lifestyle or personality characteristics have beenassociated with adaptation to shift work, including diet (vegetableintake/day), strength, lower levels of neuroticism and familyconflict. Workers who are poorly adapted to shift work may havehigher levels of interleukin-6, leptin, tumor necrosis factor alpha,and insulin. Here, TNF is linked to major depressive disorder.