Investigating the Relationship Between Sleep and Serum Hormones in Students Aged 16–25 Years

Sleep is essential for the regulation of endocrine and metabolic functions. Nonetheless, evidence regarding the correlation between habitual sleep duration and hormonal biomarkers in young adults is still insufficient, especially within Middle Eastern populations. To examine the relationship between sleep duration and serum concentrations of cortisol, melatonin, and glycated hemoglobin (HbA1c) in university students aged 16–25 years. This cross-sectional study was performed with 80 healthy students at Sulaimani Polytechnic University, Iraq. We used a structured questionnaire to find out about people's sleep habits, stress levels, and lifestyle choices. To check for serum cortisol, Chemiluminescent immunoassay was used; to check for melatonin, ELISA was used; and to check for HbA1c, HPLC was used. The duration of sleep was analyzed both continuously and categorically (<7 h vs ≥7 h). Multivariable linear regression models were used that took into account age, sex, stress, anxiety, depression, caffeine use, and smoking. The role of perceived stress as a mediator in the sleep–cortisol pathway was also investigated. The average amount of sleep was 6.9 ± 1.3 hours, and 43% of students were short sleepers. After adjustment, sleep duration did not show a significant correlation with log-transformed cortisol (β = 0.039; p = 0.39), melatonin (β = 0.63; p = 0.23), or HbA1c (β = –0.034; p = 0.57). There were no significant hormonal differences between short sleep (<7 h) and normal sleep. Stress did not influence the relationship between sleep and cortisol. Regular sleep duration did not show a significant correlation with serum cortisol, melatonin, or HbA1c levels in young students. These findings indicate that in healthy youth, moderate fluctuations in self-reported sleep may exert minimal short-term endocrine effects. Longitudinal and objective studies are necessary to elucidate these associations.