Association between Sleep Quality and Serum Cortisol, Insulin Resistance and Oxidative Stress in Adults: Cross-Sectional Study

Abstract

  Disrupted sleep has been linked to changes in the functioning of the hypothalamic pituitary adrenal axis, glucose metabolism, insulin sensitivity, and oxidative balance. The purpose of this study was to determine the relationship between sleep quality, serum cortisol, insulin resistance, metabolic markers and oxidative stress in adults. Sixty adults were grouped into good sleep quality (n = 20), poor sleep (n = 20), and very poor sleep (n = 20) based on the global Pittsburgh Sleep Quality Index (PSQI) score and analyzed using a cross sectional approach. Anthropometric measurements and fasting biochemical analyses performed in the morning comprised serum cortisol, glucose, insulin, lipid profile, malondialdehyde (MDA) and total antioxidant capacity (TAC). HOMA-IR was calculated as an estimate of insulin resistance. Group comparisons, Pearson correlation, multivariable linear regression, and receiver operating characteristic (ROC) analysis were performed. Poorer sleep quality was associated with higher serum cortisol, glucose, insulin, and HOMA-IR. Mean cortisol increased from 12.49 ± 2.10 in the good-sleep group to 18.15 ± 3.86 in the very-poor-sleep group, while HOMA-IR increased from 2.12 ± 0.47 to 3.79 ± 1.11. MDA increased from 2.17 ± 0.44 to 3.38 ± 0.65, whereas TAC decreased from 1.36 ± 0.13 to 1.09 ± 0.17. PSQI was positively correlated with cortisol (r = 0.676), HOMA-IR (r = 0.608), and MDA (r = 0.557), and negatively correlated with TAC (r = −0.597), all P < 0.001. ROC analysis showed the highest AUC for cortisol (0.877). Overall, poorer sleep quality was associated with altered cortisol regulation, greater insulin resistance, adverse metabolic characteristics, and increased oxidative stress.