Independent associations between sleep duration, gamma gap, and cognitive function among older adults: Results from the NHANES 2013-2014

Context: Increasing evidence suggests that circadian and sleep parameters influence cognitive function with aging. Objective: To evaluate observational studies of sleep duration and cognition in older adults. Data Sources: A systematic review of OVID Medline and PsycINFO through September 2015, and review of bibliographies from studies identified. Study Selection: English-language articles reporting observational studies of sleep duration and cognitive function in older populations. Data Extraction: Data extraction by 2 authors using predefined categories of desired information. Results: Thirty-two studies met our inclusion criteria, with nearly two-thirds published in the past 4 years. One-third of studies indicated that extreme sleep durations were associated with worse cognition in older adults. More studies favored an association with long vs. short sleep durations (35 vs. 26% of studies, respectively). Four studies found that greater changes in sleep duration over time were related to lower cognition. Study design and analytic methods were very heterogeneous across studies; therefore, meta-analysis was not undertaken. Limitations: We reviewed English-language manuscripts only, with a qualitative summary of studies identified. Conclusions and Implications of Key Findings: Observational studies of sleep duration and cognitive function in older adults have produced mixed results, with more studies suggesting that long (rather than short) sleep durations are related to worse cognition. Studies more consistently indicate that greater changes in sleep duration are associated with poor cognition. Future studies should be prospectively designed, with objective sleep assessment and longer follow-up periods; intervention studies are also needed to identify strategies for promoting cognitive health with aging.

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Importance of social relationships in the association between sleep duration and cognitive function: data from community-dwelling older Singaporeans

International Psychogeriatrics ◽

10.1017/s1041610217001041 ◽

2017 ◽

Vol 30 (6) ◽

pp. 893-901 ◽

Cited By ~ 2

Author(s):

Grand H.-L. Cheng ◽

Angelique Chan ◽

June C. Lo

Keyword(s):

Older Adults ◽

Social Networks ◽

Cognitive Function ◽

Sleep Duration ◽

Social Relationships ◽

Household Size ◽

Community Dwelling ◽

Policy Implications ◽

Replication Studies ◽

Nationally Representative

ABSTRACTBackground:Aging is accompanied by cognitive decline that is escalated in older adults reporting extreme sleep duration. Social relationships can influence health outcomes and thus may qualify the association between sleep duration and cognitive function. The present study examines the moderating effects of marital status, household size, and social network with friends and relatives on the sleep–cognition association among older adults.Methods:Data (N = 4,169) came from the Social Isolation, Health, and Lifestyles Survey, a nationally representative survey of community-dwelling older Singaporeans (≥ 60 years). Sleep duration and social relationships were self-reported. Cognitive function was assessed with the Short Portable Mental Status Questionnaire.Results:Regression analysis revealed that the inverted U-shaped association between sleep duration and cognitive function was less profound among older adults who were married (vs. unmarried) and those who had stronger (vs. weaker) social networks. In contrast, it was more prominent among individuals who had more (vs. fewer) household members.Conclusions:Being married and having stronger social networks may buffer against the negative cognitive impact of extreme sleep duration. But larger household size might imply more stress for older persons, and therefore strengthen the sleep duration–cognitive function association. We discuss the potential biological underpinnings and the policy implications of the findings. Although our findings are based on a large sample, replication studies using objective measures of sleep duration and other cognitive measures are needed.

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