Background: Sleep alterations can impair quality of life and contribute to disease progression
but they, and their features and contributing factors, are rarely analysed in institutionalised older
individuals. In this study, we investigated sleep alterations, the factors involved, and the role of cortisol in
sleep-related problems in institutionalised individuals.
Methods: We conducted a descriptive cross-sectional study in participants living in nursing homes in
Valencia (Spain); sleep alterations were determined based on two validated tools: the Athens insomnia
scale and Oviedo sleep questionnaire. Plasma cortisol was measured in the morning and determined by
high performance liquid chromatography-mass spectroscopy, along with other blood analytical
parameters. We also analysed any confounding factors (sleep duration, morning awakening time, intake
of hypnotic and psychotropic medication, and cognitive function).
Results: The mean age was 82.5 years (range: 65-99); approximately 80% were women and sleep
alterations were present in 25-60% of the population, depending on the scale used or type of sleep
disorder considered. There was no significant correlation between morning cortisol concentrations and
sleep disorders, sex, age, or psychotropic drug ingestion (including hypnotic drugs). However, there was a
significant correlation between cortisol and an Oviedo questionnaire subscale for evaluating insomniarelated
adverse events, which remained significant after adjusting for multiple potentially confounding
Conclusion: Sleep disorders are common in institutionalised older individuals and are not related to sleep
duration or decreased by ingestion of hypnotic medications. There is a significant relationship between
morning cortisol levels in blood and insomnia-related sleep disorders (e.g. snoring with awakenings,
nightmares, restless legs syndrome, etc.) but not directly with insomnia or hypersomnia.