Affiliation:
1. Institute of Health Informatics, University College London, London, UK
2. Department of Population Science and Experimental Medicine, Institute of Cardiovascular Science, University College London, London, UK
3. Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
Abstract
AbstractBackgroundShort and long sleep duration have been linked with poorer cognitive outcomes, but it remains unclear whether these associations are causal.MethodsWe 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.ResultsLinear 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).ConclusionsLinear increase in sleep duration has a small negative effect on reaction time and visual memory, but the true association might be non-linear, with evidence of associations for both short and long sleep duration. These findings suggest that sleep duration may represent a potential causal pathway for cognition.
Funder
Indonesian Endowment Fund For Education
British Heart Foundation
National Institute for Health Research
Wellcome Trust
Farr Institute of Health Informatics Research
Medical Research Council
Arthritis Research UK
Cancer Research UK
Economic and Social Research Council
Engineering and Physical Sciences Research Council
National Institute of Health Research
National Institute for Social Care and Health Research
Welsh Assembly Government
Chief Scientist Office
Scottish Government Health Directorates
UCL Springboard Population Science
Wellcome Trust Medical Charity
Department of Health of Scottish Government
Northwest Regional Development Agency
Publisher
Oxford University Press (OUP)
Subject
General Medicine,Epidemiology