Sleep disturbances and change in multiple cognitive domains among older adults: A multicentre study of five Nordic cohorts

• Published in: Sleep (New York, N.Y.) N.Y.), 2024, Vol.47 (3)
• Main Authors: Overton, Marieclaire, Skoog, Johan, Laukka, Erika J, Bodin, Timothy Hadarsson, Darin Mattsson, Alexander, Sjöberg, Linnea, Hofer, Scott M, Johansson, Lena, Kulmala, Jenni, Kivipelto, Miia, Solomon, Alina, Skoog, Ingmar, Kåreholt, Ingemar, Sindi, Shireen
• Format: Article
• Language: English
• Subjects: cognition; cognitive decline; cognitive domains; napping; old age; sleep disturbances
• ISSN: 1550-9109; 0161-8105; 1550-9109
• DOI: 10.1093/sleep/zsad244

We examined and compared cross-sectional and longitudinal associations between self-reported sleep disturbances and various cognitive domains in five separate Nordic European longitudinal aging studies (baseline N=5631, Mean age=77.7, Mean follow-up=4.16 years).STUDY OBJECTIVESWe examined and compared cross-sectional and longitudinal associations between self-reported sleep disturbances and various cognitive domains in five separate Nordic European longitudinal aging studies (baseline N=5631, Mean age=77.7, Mean follow-up=4.16 years).Comparable sleep parameters across studies included reduced sleep duration/quality, insomnia symptoms (sleep latency, waking up at night and early awakenings), short and long sleep duration, and daytime napping. The cognitive domains were episodic memory, verbal fluency, perceptual speed, executive functioning, and global cognition (aggregated measure). A series of mixed linear models were run separately in each study and then compared to assess the level and rate of change in cognitive functioning across each sleep disturbance parameter. Models were adjusted for age, sex, education, hypnotic usage, depressive symptoms, lifestyle factors, cardiovascular and metabolic conditions. By using a coordinated analytic approach, comparable construct-level measurements were generated and results from identical statistical models were qualitatively compared across studies.METHODSComparable sleep parameters across studies included reduced sleep duration/quality, insomnia symptoms (sleep latency, waking up at night and early awakenings), short and long sleep duration, and daytime napping. The cognitive domains were episodic memory, verbal fluency, perceptual speed, executive functioning, and global cognition (aggregated measure). A series of mixed linear models were run separately in each study and then compared to assess the level and rate of change in cognitive functioning across each sleep disturbance parameter. Models were adjusted for age, sex, education, hypnotic usage, depressive symptoms, lifestyle factors, cardiovascular and metabolic conditions. By using a coordinated analytic approach, comparable construct-level measurements were generated and results from identical statistical models were qualitatively compared across studies.While the pattern of statistically significant results varied across studies, subjective sleep disturbances were consistently associated with worse cognition and steeper cognitive decline. Insomnia symptom