Rotating shift workers reported significantly greater increases in sleep disturbance and impairment over six months compared to daytime workers.
Reductions in and were significantly linked to worsening sleep disturbance and impairment scores.
Decreased cortisol levels were associated with worsening sleep impairment, with a strong correlation (r = -0.65).
Increased levels correlated with higher sleep impairment scores.
A combined analysis indicated that both reduced cortisol and increased DHEA-S were associated with greater sleep disturbance.
Simplified
BACKGROUND: Shift work is a well-established disruptor of sleep, yet the biological mechanisms driving sleep disturbances remain poorly understood. Salivary (HPA axis), α-amylase (sympathetic-adrenomedullary output), and (adrenal androgen with anti-glucocorticoid/resilience properties) are candidate indicators of stress-related sleep disruption. We therefore examined whether changes in these biomarkers were associated with 6-month sleep trajectories in health professionals.
METHODS: In a prospective 6-month repeated-measures design, 52 healthcare professionals (daytime vs rotating shifts; mean age 31.4 ± 9.4 years; 57% female) completed validated sleep assessments, PROMIS Sleep Disturbance, PROMIS Sleep Impairment, the Sleep-Wake Disorder Index (SWDI), and the NIH 7-day Sleep Diary, at baseline and six-month follow-up. Salivary cortisol, Dehydroepiandrosterone Sulfate (DHEA-S), and were collected on the morning of Day 7 of each diary period. Change scores (Δ = follow-up - baseline) were computed. Repeated-measures ANOVA, Pearson correlations, and multivariable regressions assessed group differences and biomarker-sleep associations.
RESULTS: Compared with daytime workers, rotating shift workers reported significantly greater increases in sleep disturbance, impairment, and reduced sleep efficiency over time (all p < 0.05). Reductions in cortisol and alpha-amylase were significantly associated with worsening PROMIS Sleep Disturbance and SWDI scores (r = -0.65 and -0.53, respectively; p < 0.05). Multivariable regression showed that decreased cortisol (β = -41.845, p = 0.0064) and increased DHEA-S (β = 0.001, p = 0.0405) associated with worsening PROMIS Sleep Impairment. A combined model including reduced cortisol, and increased DHEA-S associated with greater PROMIS Sleep Disturbance (adjusted= 0.698). R²
CONCLUSION: In this pilot, changes in salivary cortisol and DHEA-S were associated with longitudinal changes in sleep. These results suggest potential utility for biomarker-informed risk stratification, warranting confirmation in larger, controlled studies.
Key numbers
0.65
Increase in Sleep Disturbance
Correlation coefficient between changes and sleep disturbance scores.
0.59
Increase in Sleep Impairment
Correlation coefficient between changes and sleep impairment scores.
52
Sample Size
Total number of healthcare professionals enrolled in the study.
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All authors declare no conflict of interest. The authors also disclose a related preprint: Associations Between Salivary Cortisol, DHEA-S, and Alpha-Amylase and Longitudinal Sleep Disruption in Shift-Working Healthcare Professionals: A Pilot Study (Mohammed F. Salahuddin, Karn Sukararuji, Mahsa Sharifi, Kingsley Anetor Francis Odia, Md Dilshad Manzar, Seithikurippu R. Pandi-Perumal, Ahmed S. BaHammam). doi: https://doi.org/10.1101/2025.09.19.25336161
