The relationship between sleep duration, cognition and dementia: a Mendelian randomization study

Topic: Risk, prevention and care in population studies

Background Short and long sleep duration have been linked with poorer cognitive outcomes, but it remains unclear whether these associations are causal. Methods We conducted the first Mendelian randomization (MR) study with 77 single-nucleotide polymorphisms (SNPs) for sleep duration using individual-participant data from the UK Biobank cohort (N = 395 803) and summary statistics from the International Genomics of Alzheimer's Project (N cases/controls = 17 008/37 154) to investigate the potential impact of sleep duration on cognitive outcomes. Results Linear MR suggested that each additional hour/day of sleep was associated with 1% [95% confidence interval (CI) = 0-2%; P = 0.008] slower reaction time and 3% more errors in visual-memory test (95% CI = 0-6%; P = 0.05).

Key findings

• Methods We conducted the first Mendelian randomization (MR) study with 77 single-nucleotide polymorphisms (SNPs) for sleep duration using individual-participant data from the UK Biobank cohort (N = 395 803) and summary statistics from the International Genomics of Alzheimer's Project (N cases/controls = 17 008/37 154) to investigate the potential impact of sleep duration on cognitive outcomes.
• Results Linear MR suggested that each additional hour/day of sleep was associated with 1% [95% confidence interval (CI) = 0-2%; P = 0.008] slower reaction time and 3% more errors in visual-memory test (95% CI = 0-6%; P = 0.05).
• There was little evidence to support associations of increased sleep duration with decline in visual memory [odds ratio (OR) per additional hour/day of sleep = 1.10 (95% CI = 0.76-1.57); P = 0.62], decline in reaction time [OR = 1.28 (95% CI = 0.49-3.35); P = 0.61], all-cause dementia [OR = 1.19 (95% CI = 0.65-2.19); P = 0.57] or Alzheimer's disease risk [OR = 0.89 (95% CI = 0.67-1.18); P = 0.41].
• Non-linear MR suggested that both short and long sleep duration were associated with poorer visual memory (P for non-linearity = 3.44e-9) and reaction time (P for non-linearity = 6.66e-16).

Why it matters

This genetic analysis suggested that each additional hour of sleep per day was linked to slightly slower reaction time and slightly more errors in a visual-memory test. It did not establish that changing sleep duration would prevent dementia.

Study details

• Participants395
• Effect sizeOR = 1.28; OR = 1.19; OR = 0.89
• Evidence strengthModerate

Read the original

• DOI: 10.1093/ije/dyz071
• PubMed: 31062029
• Original source →
• Free full text: International Journal of Epidemiology →

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

@article{henry2019-31062029,
  author  = {Henry, A. and Katsoulis, M. and Masi, S. and Fatemifar, G. and Denaxas, S. and Acosta, D. and Garfield, V. and Dale, C. E.},
  title   = {{The relationship between sleep duration, cognition and dementia: a Mendelian randomization study}},
  journal = {International journal of epidemiology},
  year    = {2019},
  doi     = {10.1093/ije/dyz071},
  pmid    = {31062029},
  url     = {https://doi.org/10.1093/ije/dyz071}
}

Studies this one cites

Referenced by this study and also in the alzhub library, so you can read them here.

• UK Biobank: An Open Access Resource for Identifying the Causes of a Wide Range of Complex Diseases of Middle and Old Age PLoS Medicine · 2015-03-31 · usefulness score 77/100 · Long-term cohort studies
• Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease Nature Genetics · 2013-10-27 · usefulness score 66/100 · Risk genes beyond APOE
• Prolonged sleep duration as a marker of early neurodegeneration predicting incident dementia Neurology · 2017-02-22 · usefulness score 62/100 · Long-term cohort studies
• Sleep architecture and the risk of incident dementia in the community Neurology · 2017-08-23 · usefulness score 56/100 · Long-term cohort studies
• The elephant in the room - healthy brains in later life, epidemiology and public health Nature reviews. Neuroscience · 2007-02-14 · usefulness score 45/100 · Prevention and risk

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• Genetic Risk of Alzheimer's Disease and Sleep Duration in Non-Demented Elders Annals of neurology · 2020-10-05 · usefulness score 46/100 · Long-term cohort studies
• Observational studies in Alzheimer disease: bridging preclinical studies and clinical trials Nature reviews. Neurology · 2022-10-31 · usefulness score 42/100 · Treatments

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