Review Article | Published:

The changing prevalence and incidence of dementia over time — current evidence

Nature Reviews Neurology volume 13, pages 327339 (2017) | Download Citation

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Abstract

Dementia is an increasing focus for policymakers, civil organizations and multidisciplinary researchers. The most recent descriptive epidemiological research into dementia is enabling investigation into how the prevalence and incidence are changing over time. To establish clear trends, such comparisons need to be founded on population-based studies that use similar diagnostic and research methods consistently over time. This narrative Review synthesizes the findings from 14 studies that investigated trends in dementia prevalence (nine studies) and incidence (five studies) from Sweden, Spain, the UK, the Netherlands, France, the USA, Japan and Nigeria. Besides the Japanese study, these studies indicate stable or declining prevalence and incidence of dementia, and some provide evidence of sex-specific changes. No single risk or protective factor has been identified that fully explains the observed trends, but major societal changes and improvements in living conditions, education and healthcare might have favourably influenced physical, mental and cognitive health throughout an individual's life course, and could be responsible for a reduced risk of dementia in later life. Analytical epidemiological approaches combined with translational neuroscientific research could provide a unique opportunity to explore the neuropathology that underlies changing occurrence of dementia in the general population.

Key points

  • Knowledge of changes in dementia occurrence can only be acquired through population-based studies conducted at different time periods in representative samples derived from the same populations

  • Such studies must use diagnostic and research methods that are as similar as feasible across time to enable valid comparisons

  • We synthesize worldwide evidence from 14 such population-based studies across Western Europe, the USA, Japan and Nigeria; most have reported declining or stable prevalence and incidence with varying sex differences across countries

  • No single risk or protective factor has explained these changes, but societal changes in western societies have improved cognitive reserve and health status across the lifecourse

  • Integrating analytical epidemiological approaches and neuroscience within population-based studies is key to understanding the changes observed, underlying neurobiological mechanisms, and what policies might sustain such improvements

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Change history

  • 17 May 2017

    In the version of this article initially published online, the affiliations for Karine Pérès, Chengxuan Qiu and Britt-Marie Sjölund were incorrect. These errors have been corrected in the print, HTML and PDF versions of the article.

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Acknowledgements

We would like to thank Ms Lesile Grasset (Bordeaux study), Dr Sujuan Gao (Indianapolis–Idaban Dementia Project) and Professor Anders Wimo (Nordanstig study) for providing age-specific and sex-specific prevalence and incidence estimates.

Author information

Affiliations

  1. REACH: The Centre for Research in Ageing and Cognitive Health, Department of Psychology, College of Life and Environmental Sciences, University of Exeter, Washington Singer Building, Perry Road, Exeter EX4 4QG, UK.

    • Yu-Tzu Wu
  2. Boston University School of Public Health, 72 East Concord St, B602 Boston, Massachusetts 02118, USA.

    • Alexa S. Beiser
  3. German Center for Neurodegenerative diseases (DZNE), Population Health Sciences, Sigmund-Freud-Straße 27, 53127 Bonn, Germany.

    • Monique M. B. Breteler
  4. Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Stockholm University, Gävlegatan 16, S-113 30, Stockholm, Sweden.

    • Laura Fratiglioni
    • , Chengxuan Qiu
    •  & Britt-Marie Sjölund
  5. INSERM, ISPED, Centre INSERM, U1219 - Bordeaux Population Health Research Center, Bordeaux, France.

    • Catherine Helmer
    •  & Karine Pérès
  6. Department of Psychiatry, Indiana University School of Medicine, 410 West 10th Street, Indianapolis, Indiana 46202, USA.

    • Hugh C. Hendrie
  7. Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, 812–8582, Fukuoka, Japan.

    • Hiroyuki Honda
  8. Department of Epidemiology, Erasmus University Medical Center, Wytemaweg 80, 3015 CN Rotterdam, Netherlands.

    • M. Arfan Ikram
  9. Department of Internal Medicine, Veterans Affairs Center for Clinical Management Research, Institute for Social Research, and Institute for Healthcare Policy and Innovation, University of Michigan, 2800 Plymouth Road, Ann Arbor, Michigan 48109–2800, USA.

    • Kenneth M. Langa
  10. Department of Psychiatry, Universidad de Zaragoza and Instituto de Investigación Sanitaria Aragón, Zaragoza. CIBERSAM, Madrid, Spain.

    • Antonio Lobo
  11. Institute of Health and Society, Newcastle University, The Baddiley-Clark Building, Richardson Road, Newcastle Upon Tyne, NE4 5PL, UK.

    • Fiona E. Matthews
  12. Department of Epidemiology and Public Health, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, 812–8582, Fukuoka, Japan.

    • Tomoyuki Ohara
  13. Boston University School of Medicine, The Framingham Study, 72 East Concord Street, B602 Boston, Massachusetts 02118, USA.

    • Sudha Seshadri
  14. Centre for Ageing and Health AgeCap, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Box 100, S-405 30, Gothenburg, Sweden.

    • Ingmar Skoog
  15. Department of Public Health and Primary Care, Cambridge Institute of Public Health, Forvie Site, University of Cambridge, School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge CB2 0SR, UK.

    • Carol Brayne

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Contributions

All authors researched data for the article and reviewed and/or edited the manuscript before submission. Y.-T.W. and C.B. wrote the article and made substantial contributions to discussion of the content.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Carol Brayne.

Supplementary information

Word documents

  1. 1.

    Supplementary information S1 (table)

    Prevalence studies

  2. 2.

    Supplementary information S2 (table)

    Incidence studies: estimates by 10-year age group

  3. 3.

    Supplementary information S3 (table)

    Incidence studies: estimates by 5-year age group

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DOI

https://doi.org/10.1038/nrneurol.2017.63

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