TNF and obesity due to melanocortin 4 receptor deficiency: In some other studies, the serum IL-6 and CRP, but not the TNF-α, concentrations were related to obesity rather than type 2 diabetes [22,31], although results from a prospective health study of middle-aged American women found increasing plasma levels of CRP, IL-6 and MCP-1 to be associated with a higher risk of developing type 2 diabetes, relationships that although attenuated continued to possess a high level of statistical significance after adjustment for the BMI [32].