Study On Correlation Between Salivary Cortisol Level And Sleep Quality

Background With the progress of the times, and rapid development of social economy, people’s lives rhythm is also accelerating, resulting from business, pressure. As a result, people face with more different health risks, negative emotions and sleep disorders. Good sleep quality is helpful to improve people’s work, life, learning efficiency and maintain a better social adaptability. Cortisol,secretion of the adrenal cortex, is an important component of the human endocrine system, the hypothalamus pituitary adrenal axis (HPA axis) circadian rhythm will affect its level fluctuations. The circadian rhythm of cortisol levels has many functions, such as regulating neuroendocrine, making internal environment stable, regulating immunity, preventing oxidation, regulating human body’s normal sleep cycle, adapting to the environment changes, and coordinating human physiological responses.Objective Investigate the relationship between salivary cortisol and sleep quality, and application of salivary cortisol testing to evaluate sleep disorder clincally.Methods Use cluster sampling method to investigate the staff of the two large firms in Hangzhou.According to the criteria of inclusion and exclusion,571 adults were selected as the research objects (the age of 20 to 60). And collect the data of age, gender, height, weight, Collect the samples of saliva, Determination of salivary cortisol level by photochemical method. Pittsburgh sleep quality index (PSQI) was used to evaluate a month’s sleep qualities of subjects.Results There were 46.8% of the objects in study who had a sleep disorder, and the sleep quality of female subjects was worse than that of male subjects. Positive correlation was found between salivary cortisol levels and PSQI scores in the object of study (spearman rank correlation coefficient=0.632, p<0.01), Male subjects operating characteristic curve(ROC) analysis was used to assess the performance of salivary cortisol in the diagnosis of sleep disorder.The area under the curve was 0.873 (95% confidence interval:0.839-0.911),close to the upper left corner of the ROC curve of the upper left corner of the salivary cortisol levels of 6.55nmol/L is the optimal cut-off value. The corresponding sensitivity is 78.5%,specificity is 84.0%.The area under the curve (AUC) of female was 0.885(95% confidence interval:0.841--0.929), and the upper left corner of the ROC curve of the upper left corner of the salivary cortisol levels of 7.40nmol/L for screening test best critical point, its corresponding sensitivity was 68.3%,specificity was 87.8%.Conclusions Saliva cortisol levels and the quality of sleep have a strong correlation, Saliva cortisol levels of sleep disorder group was obviously higher than that of normal group. Salivary cortisol testing may be considered as an auxiliary means of sleep disorder diagnosis.