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Published on: November 6, 2017
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The relationship between sleep duration, cognition and dementia: a Mendelian randomization study
Albert Henry1,2, Michail Katsoulis1, Stefano Masi2,3
1Institute of Health Informatics, University College London, London, UK.
International Journal of Epidemiology
|May 8, 2019
Summary
Investigating sleep duration and cognition, this study found that while a linear increase in sleep time may slightly impair reaction time and visual memory, the true relationship is likely non-linear. Both short and long sleep durations are associated with poorer cognitive outcomes, suggesting sleep duration is a potential causal factor for cognition.
Area of Science:
- Genetics
- Neuroscience
- Epidemiology
Background:
- Associations between sleep duration and cognitive function are established, but causality remains uncertain.
- Previous studies have not definitively determined if sleep duration causally impacts cognitive outcomes.
Purpose of the Study:
- To investigate the causal relationship between sleep duration and cognitive outcomes using Mendelian randomization.
- To examine the impact of both short and long sleep durations on cognitive performance.
Main Methods:
- Employed Mendelian randomization (MR) with 77 single-nucleotide polymorphisms (SNPs) for sleep duration.
- Utilized individual-participant data from the UK Biobank and summary statistics from the International Genomics of Alzheimer's Project.
- Applied both linear and non-linear MR analyses to assess cognitive outcomes.
Main Results:
- Linear MR indicated a small negative effect of increased sleep duration on reaction time and visual memory.
- Non-linear MR revealed significant associations between both short and long sleep durations and poorer visual memory and reaction time.
- No significant evidence supported associations between increased sleep duration and cognitive decline, dementia, or Alzheimer's disease risk in linear analyses.
Conclusions:
- The relationship between sleep duration and cognitive function is likely non-linear.
- Both insufficient and excessive sleep durations are associated with adverse cognitive outcomes.
- Sleep duration may represent a potential causal pathway influencing cognition.
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