Non-linear associations between sleep duration and the risks of mild cognitive impairment/dementia and cognitive decline: a dose–response meta-analysis of observational studies



Mount evidence from observational studies suggested that associations between sleep duration and the risks of mild cognitive impairment (MCI)/dementia or cognitive decline had been recognized.


To explore the precise and continuous effect of sleep duration on these risks, we conducted a dose–response meta-analysis to quantitatively assess it.


Five prospective cohort studies and 4 cross-sectional studies were eligible for inclusion criteria, which involved 62937 individuals, and documented 2718 MCI/dementia cases and 5596 cognitive decline cases. The pooled RR per 1 h increases in sleep duration was 0.99 (95% CI 0.97–1.01, I2 = 62.40%, P = 0.02, n = 6) for cognitive decline risk, and 0.98 (95% CI 0.97–1.00, I2 = 0%, P = 0.42, n = 4) for MCI/dementia risk. Similar U-shaped non-linear relationship of sleep duration and the risks of MCI/dementia and cognitive decline was revealed, respectively (all Pnon-linearity < 0.001), whose peaks are approximately 7 h.


In conclusion, 7 h sleep duration tends to acquire the least risk of MCI/dementia or cognitive decline; however, more well-designed randomized controlled trials are urgently needed to balance potential modifiers.

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Mild cognitive impairment


Relative risk


Confidence interval


The mini-mental state examination


Telephone interview for cognitive status


The east Boston memory test


  1. 1.

    Korczyn AD (2005) The underdiagnosis of the vascular contribution to dementia. J Neurol Sci 229–230:3–6.

    Article  PubMed  Google Scholar 

  2. 2.

    Alzheimer's Association Report (2010) Alzheimer’s disease facts and figures. Alzheimer’s Dement J Alzheimer’s Assoc 6:158–194.

    Article  Google Scholar 

  3. 3.

    Myers BL, Badia P (1995) Changes in circadian rhythms and sleep quality with aging: mechanisms and interventions. Neurosci Biobehav Rev 19:553–571

    Article  CAS  PubMed  Google Scholar 

  4. 4.

    Qureshi AI, Giles WH, Croft JB et al (1997) Habitual sleep patterns and risk for stroke and coronary heart disease: a 10-year follow-up from NHANES I. Neurology 48:904–911

    Article  CAS  PubMed  Google Scholar 

  5. 5.

    Chen JC, Brunner RL, Ren H et al (2008) Sleep duration and risk of ischemic stroke in postmenopausal women. Stroke 39:3185–3192.

    Article  PubMed  PubMed Central  Google Scholar 

  6. 6.

    Ayas NT, White DP, Al-Delaimy WK et al (2003) A prospective study of self-reported sleep duration and incident diabetes in women. Diabetes Care 26:380–384

    Article  PubMed  Google Scholar 

  7. 7.

    Yaggi HK, Araujo AB, McKinlay JB (2006) Sleep duration as a risk factor for the development of type 2 diabetes. Diabetes Care 29:657–661

    Article  PubMed  Google Scholar 

  8. 8.

    Meisinger C, Heier M, Lowel H et al (2007) Sleep duration and sleep complaints and risk of myocardial infarction in middle-aged men and women from the general population: the MONICA/KORA Augsburg cohort study. Sleep 30:1121–1127

    Article  PubMed  PubMed Central  Google Scholar 

  9. 9.

    Ayas NT, White DP, Manson JE et al (2003) A prospective study of sleep duration and coronary heart disease in women. Arch Intern Med 163:205–209

    Article  PubMed  Google Scholar 

  10. 10.

    Bokenberger K, Strom P, Dahl Aslan AK et al (2017) Association between sleep characteristics and incident dementia accounting for baseline cognitive status: a prospective population-based study. J Gerontol Ser A Biol Sci Med Sci 72:134–139.

    Article  Google Scholar 

  11. 11.

    Chen JC, Espeland MA, Brunner RL et al (2016) Sleep duration, cognitive decline, and dementia risk in older women. Alzheimer’s Dement J Alzheimer’s Assoc 12:21–33.

    Article  Google Scholar 

  12. 12.

    Virta JJ, Heikkila K, Perola M et al (2013) Midlife sleep characteristics associated with late life cognitive function. Sleep 36:1533–1541. 1541a.

    Article  PubMed  PubMed Central  Google Scholar 

  13. 13.

    Ramos AR, Dong C, Elkind MS et al (2013) Association between sleep duration and the mini-mental score: the Northern Manhattan study. J Clin Sleep Med JCSM Off Publ Am Acad Sleep Med 9:669–673.

    Article  Google Scholar 

  14. 14.

    Keage HA, Banks S, Yang KL et al (2012) What sleep characteristics predict cognitive decline in the elderly? Sleep Med 13:886–892.

    Article  PubMed  Google Scholar 

  15. 15.

    Xu L, Jiang CQ, Lam TH et al (2011) Short or long sleep duration is associated with memory impairment in older Chinese: the Guangzhou Biobank Cohort Study. Sleep 34:575–580

    Article  PubMed  PubMed Central  Google Scholar 

  16. 16.

    Loerbroks A, Debling D, Amelang M et al (2010) Nocturnal sleep duration and cognitive impairment in a population-based study of older adults. Int J Geriatr Psychiatry 25:100–109.

    Article  PubMed  Google Scholar 

  17. 17.

    Faubel R, Lopez-Garcia E, Guallar-Castillon P et al (2009) Usual sleep duration and cognitive function in older adults in Spain. J Sleep Res 18:427–435.

    Article  PubMed  Google Scholar 

  18. 18.

    Benito-Leon J, Bermejo-Pareja F, Vega S et al (2009) Total daily sleep duration and the risk of dementia: a prospective population-based study. Eur J Neurol 16:990–997.

    Article  CAS  PubMed  Google Scholar 

  19. 19.

    Schmutte T, Harris S, Levin R et al (2007) The relation between cognitive functioning and self-reported sleep complaints in nondemented older adults: results from the Bronx aging study. Behav Sleep Med 5:39–56.

    Article  PubMed  Google Scholar 

  20. 20.

    Ferrie JE, Shipley MJ, Akbaraly TN et al (2011) Change in sleep duration and cognitive function: findings from the Whitehall II Study. Sleep 34:565–573

    Article  PubMed  PubMed Central  Google Scholar 

  21. 21.

    Kronholm E, Sallinen M, Suutama T et al (2009) Self-reported sleep duration and cognitive functioning in the general population. J Sleep Res 18:436–446.

    Article  PubMed  Google Scholar 

  22. 22.

    Ohayon MM, Vecchierini MF (2002) Daytime sleepiness and cognitive impairment in the elderly population. Arch Intern Med 162:201–208

    Article  PubMed  Google Scholar 

  23. 23.

    Blackwell T, Yaffe K, Ancoli-Israel S et al (2006) Poor sleep is associated with impaired cognitive function in older women: the study of osteoporotic fractures. J Gerontol Ser A Biol Sci Med Sci 61:405–410

    Article  Google Scholar 

  24. 24.

    Tworoger SS, Lee S, Schernhammer ES et al (2006) The association of self-reported sleep duration, difficulty sleeping, and snoring with cognitive function in older women. Alzheimer Dis Assoc Disord 20:41–48.

    Article  PubMed  Google Scholar 

  25. 25.

    Moher D, Liberati A, Tetzlaff J et al (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Open medicine: a peer-reviewed. Indep Open Access J 3:e123-130

    Google Scholar 

  26. 26.

    Wells GA, Shea B, O'Connell D et al (2014) The Newcastle-Ottawa Scale (NOS) for Assessing the Quality of Nonrandomised Studies in Meta-analyses. Ottawa: Ottawa Hospital Research Institute. Accessed 17 Feb 2014

  27. 27.

    Orsini N, Bellocco R, Greenland S (2006) Generalized least squares for trend estimation of summarized dose–response data. Stata J 6:40–57

    Article  Google Scholar 

  28. 28.

    DerSimonian R, Laird N (1986) Meta-analysis in clinical trials. Control Clin Trials 7:177–188

    Article  CAS  Google Scholar 

  29. 29.

    Higgins JP, Thompson SG, Deeks JJ et al (2003) Measuring inconsistency in meta-analyses. BMJ 327:557–560.

    Article  PubMed  PubMed Central  Google Scholar 

  30. 30.

    Liu Q, Cook NR, Bergström A et al (2009) A two-stage hierarchical regression model for meta-analysis of epidemiologic nonlinear dose–response data. Comput Stat Data Anal 53:4157–4167.

    Article  Google Scholar 

  31. 31.

    Desquilbet L, Mariotti F (2010) Dose-response analyses using restricted cubic spline functions in public health research. Stat Med 29:1037–1057.

    Article  PubMed  Google Scholar 

  32. 32.

    Yaffe K, Falvey CM, Hoang T (2014) Connections between sleep and cognition in older adults. Lancet Neurol 13:1017–1028.

    Article  PubMed  Google Scholar 

  33. 33.

    Benito-Leon J, Louis ED, Villarejo-Galende A et al (2014) Long sleep duration in elders without dementia increases risk of dementia mortality (NEDICES). Neurology 83:1530–1537.

    Article  PubMed  PubMed Central  Google Scholar 

  34. 34.

    Nebes RD, Buysse DJ, Halligan EM et al (2009) Self-reported sleep quality predicts poor cognitive performance in healthy older adults. J Gerontol Ser B Psychol Sci Soc Sci 64:180–187.

    Article  Google Scholar 

  35. 35.

    Foley D, Monjan A, Masaki K et al (2001) Daytime sleepiness is associated with 3-year incident dementia and cognitive decline in older Japanese–American men. J Am Geriatr Soc 49:1628–1632

    Article  CAS  PubMed  Google Scholar 

  36. 36.

    Quesnot A, Alperovitch A (1999) Snoring and risk of cognitive decline: a 4-year follow-up study in 1389 older individuals. J Am Geriatr Soc 47:1159–1160

    Article  CAS  PubMed  Google Scholar 

  37. 37.

    Kim HB, Myung SK, Lee SM et al (2016) Longer duration of sleep and risk of cognitive decline: a meta-analysis of observational studies. Neuroepidemiology 47:171–180.

    Article  PubMed  Google Scholar 

  38. 38.

    Goel N, Rao H, Durmer JS et al (2009) Neurocognitive consequences of sleep deprivation. Semin Neurol 29:320–339.

    Article  PubMed  PubMed Central  Google Scholar 

  39. 39.

    Ohayon MM, Vecchierini MF (2005) Normative sleep data, cognitive function and daily living activities in older adults in the community. Sleep 28:981–989

    Article  PubMed  Google Scholar 

  40. 40.

    Cohen-Zion M, Stepnowsky C, Shochat T et al (2001) Changes in cognitive function associated with sleep disordered breathing in older people. J Am Geriatr Soc 49:1622–1627

    Article  CAS  PubMed  Google Scholar 

  41. 41.

    Kang JE, Lim MM, Bateman RJ et al (2009) Amyloid-beta dynamics are regulated by orexin and the sleep-wake cycle. Science 326:1005–1007.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. 42.

    Kronholm E, Harma M, Hublin C et al (2006) Self-reported sleep duration in Finnish general population. J Sleep Res 15:276–290.

    Article  PubMed  Google Scholar 

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Supported by Medical Scientific Research Foundation of Guangdong Province, China (Grant No. A2017392) and Traditional Chinese Medicine Bureau Of Guangdong Province (Grant No. 20181184).

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YL wrote the main manuscript. HL provided the study idea. YL and LBQ conducted article screening and literature search. HL made critical comments and revision for the manuscript. All authors reviewed and approved the final manuscript.

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Correspondence to Hao Liu.

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Liang, Y., Qu, LB. & Liu, H. Non-linear associations between sleep duration and the risks of mild cognitive impairment/dementia and cognitive decline: a dose–response meta-analysis of observational studies. Aging Clin Exp Res 31, 309–320 (2019).

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  • Sleep duration
  • Mild cognitive impairment (MCI)
  • Dementia
  • Cognitive decline
  • Dose–response
  • Meta-analysis