The mediating role of low-grade inflammation on the prospective association between sleep and cognitive function in older men and women: 8-year follow-up from the English Longitudinal Study of Ageing

Marta Jackowska, Dorina Cadar

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Abstract

Suboptimalsleep patterns predict poorer cognitive function in older adults and induce inflammatory responses.  Inflammation could also adversely affectcognitive function.  This study exploredwhether systemic inflammation may be one biological mechanism through whichsleep influences cognitive performance.  Participants were 4877 men and women from theEnglish Longitudinal Study of Ageing who were followed-up for 8 years starting at wave 4 (2008-09), throughwave 6 (2012-13), and until wave 8 (2016-17). Sleep quality and duration were measuredwith self-reported questionnaires.  Cognitivefunction was assessed objectively with testsof verbal fluency, memory (immediate and delayed recall) and time orientation.  Analyses were stratified by sex and adjustedfor socio-economic circumstances, health behaviours, limiting long-standingillness, medication, depressive symptoms, and baseline inflammation andcognition.  In men, in comparison withoptimal sleep duration, short sleep (≤6 h: β = -0.343, C.I. -0.611 to -0.076; >6-7 h: β = -0.263, C.I. -0.506 to -0.020) andlong sleep (β = -0.536, C.I. -1.019 to -0.053) measured at baseline predictedlower scores in delayed memory recall at follow-up.  In women, sleep duration was unrelated tocognitive performance at follow-up, and in both sexes, there was norelationship between sleep quality and follow-up cognitive performance.  There was no evidence of mediating effects of inflammatory markers inthe relationship between sleep measures and cognitive performance in bothsexes.  In conclusion, baseline short andlong sleep duration is associated with follow-up cognitive performance in older men,but we found no evidence of any mediatingeffects of inflammation. 


© 2019, Elsevier B.V. All rights reserved. The attached document (embargoed until 03/11/2020) is an author produced version of a paper published in ARCHIVES OF GERONTOLOGY AND GERIATRICS uploaded in accordance with the publisher’s self-archiving policy. The final published version (version of record) is available online at the link. Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.

Original languageEnglish
Article number103967
JournalArchives of Gerontology and Geriatrics
Volume87
Early online date3 Nov 2019
DOIs
Publication statusE-pub ahead of print - 3 Nov 2019

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