TNF and Obesity: A longer sleep duration leads to increased proinflammatory cytokine release, specifically of interleukin-1 (IL-1) and tumor necrosis factor (TNF), which play a role in new tumor growth.[31] The shorter sleep duration also increased the level of the inflammatory factor and increased risk of CRC, compared with the 7 hours, and the TNF-a level increased by 8%.[33] Moreover, having a longer sleep duration increases cortisol secretion along with insulin resistance, resulting in obesity; short sleep time can also lead to obesity, obesity is an independent risk factor for CRC.