All the glycemic measurements, including fasting plasma glucose (FPG), plasma glucose two hours after glucose load (2hPG), and HbA1c, as well as HOMA-IR, exhibited a significant negative correlation with the leptin levels when analyzed within all participants, but not separately in either DM or NGT groups. No significant correlation of leptin with age or fasting insulin level was found in any of the groups. The gene discussed is LEP; the disease is diabetes mellitus.