Irisin and leptin concentrations in relation to obesity, and developing type 2 diabetes: A cross sectional and a prospective case-control study nested in the Normative Aging Study

Leptin concentrations are higher in the obese group irrespective of their glucose tolerance. Obese individuals with impaired fasting glucose have higher concentrations of circulating irisin compared to non-obese subjects with normal glucose tolerance. Irisin concentrations do not predict risk of developing diabetes prospectively.