The Influence of Cortisol and Age Differences on the Development of Insulin Resistance and Dyslipidemia in Euthyroid Patients

Objectives: The present study was planned to investigate the influence of serum cortisol and age differences on insulin resistance and the associated lipid disturbances in euthyroid adults.
Methods: Hyperglycemic, hyperinsulinemic patients were recruited, and classified according to their insulin resistance (HOMA-IR) into: Normal insulin sensitivity (NIS), moderate- (MIR), high insulin resistance (HIR) with HOMA-IR<4, 4.1 to 6, and >6, respectively. The patients were also classified into three age-range groups: young age (YA), middle age (MA), Old age (OA); with age ranges <30, 31-40 and >40 yrs., respectively. Fasting serum was used for analysis.
Results: The serum cortisol of HIR was higher than NIS by 17.64%, and insulin higher than NIS and MIR by 272% and 121%, respectively. On the other hand, serum glucose of OA was higher than YA by 28.87%, whereas, insulin was lower than YA and MA by 52.08%, and 31.10%. Similarly, HOMA-IR was lower than YA and MA by 45.97% and 24.11%, respectively. There was significant correlation between serum cortisol and HOMA-IR (R=0.59, P=0.02) at ages> 45 years. Serum triglyceride in HIR was higher than NIS and MIR by 38.59% and 18.79%, and VLDL by 116% and 20.37%, respectively, whereas, HDL was lower than NIS by 11.38%.
Conclusion: Insulin resistant patients had elevated serum cortisol and insulin. There was significant correlation between cortisol and insulin resistance at older ages. The serum cortisol increased with age whereas insulin level decreased. Patients with high insulin resistance had dyslipidemia characterized by high serum TG, high VLDL-c and low HDL-c.