Skip to main content

Estimates of the prevalence, incidence and severity of dementia in Ireland

  • T. Pierse (a1), E. O’ Shea (a1) and P. Carney (a1)

In this paper we provide revised estimates of the prevalence of dementia in Ireland, the number of new cases per year and the severity mix. These estimates are a necessary input for any assessment of the potential demand for services and supports for people with dementia across all care settings in Ireland.


The prevalence, incidence and severity stage of dementia are calculated by applying rates from prominent international studies to population data from the 2016 census.


We show that the total number of people with dementia in Ireland ranges between 39 272 and 55 266, depending on the international rates used to measure prevalence. The incidence of dementia in Ireland has increased as the population has aged, to at least 7752 new cases per year. We estimate that there are at least 11 175 people living at home in the community in Ireland with dementia who have a serious functional impairment, based on an Activities of Daily Living measurement, of which an estimated 1876 are chair or bedbound.


Without a national prevalence study it is not possible to be precise about the estimates of the number of people with dementia in Ireland. However, having credible upper and lower bound estimates for the number of people with dementia, the potential number of new cases per year and severity rates is useful for planners and those charged with the responsibility of making resource allocation decisions in dementia.

Corresponding author
*Address for correspondence: T. Pierse, Postdoctoral Researcher, Centre for Economic and Social Research on Dementia, ILAS Building, NUI Galway, Galway, Ireland. (Email:
Hide All
ADI (2015). World Alzheimer Report 2015: The Global Impact of Dementia . Alzheimer’s Disease International: London.
Alzheimer’s Disease International (ADI) (2009). World Alzheimer’s Report 2009. Alzheimer’s Disease International: London.
Alzheimer Europe (2009). EUROCODE: Report of WP 7 2006 Prevalence of Dementia in Europe.
Andersen, K, Lolk, A, Nielsen, H, Andersen, J, Olsen, C, Kragh‐Ssrensen, P (1997). Prevalence of very mild to severe dementia in Denmark. Acta Neurologica Scandinavica 96, 8287.
Boersma, F, Eefsting, JA, van den Brink, W, Koeter, M, van Tilburg, W (1998). Prevalence of dementia in a rural Netherlands population and the influence of DSM-III-R and CAMDEX criteria for the prevalence of mild and more severe forms. Journal of Clinical Epidemiology 51, 189197.
Brayne, C, Calloway, P (1989). An epidemiological study of dementia in a rural population of elderly women. The British Journal of Psychiatry 155, 214219.
Cahill, S, Diaz-Ponce, AM, Coen, RF, Walsh, C (2010). The underdetection of cognitive impairment in nursing homes in the Dublin area. The need for on-going cognitive assessment. Age and Ageing 39, 128131.
Central Statistics Office (CSO) (2013). Population and Labour Force Projections. Central Statistics Office: Dublin, Ireland. ( Accessed 9 May 2016.
Central Statistics Office (CSO) (2016). Census 2016. Central Statistics Office: Cork.
Clarke, M, Jagger, C, Anderson, J, Battcock, T, Kelly, F, Stern, MC (1991). The prevalence of dementia in a total population: a comparison of two screening instruments. Age and Ageing 20, 396403.
Donnelly, DS, O’Brien, DM, Begley, DE, Brennan, MJ (2016). “I’d prefer to stay at home but I don’t have a choice”: meeting older people’s preference for care: policy, but what about practice? University College Dublin, Dublin.
Erkinjuntti, T, Østbye, T, Steenhuis, R, Hachinski, V (1997). The effect of different diagnostic criteria on the prevalence of dementia. New England Journal of Medicine 337, 16671674.
Ferri, CP, Prince, M, Brayne, C, Brodaty, H, Fratiglioni, L, Ganguli, M, Hall, K, Hasegawa, K, Hendrie, H, Huang, Y (2006). Global prevalence of dementia: a Delphi consensus study. The Lancet 366, 21122117.
Fratiglioni, L, Forsell, Y, Agüero Torres, H, Winblad, B (1994). Severity of dementia and institutionalization in the elderly: prevalence data from an urban area in Sweden. Neuroepidemiology 13, 7988.
Galeotti, F, Giusti, A, Meduri, F, Raschetti, R, Scardetta, P, Vanacore, N (2013). Epidemiological Data on Dementia: Synthesis Report. ALzheimer COoperation Valuation in Europe (ALCOVE), Paris.
Garre-Olmo, J, Vilalta-Franch, J, Calvó-Perxas, L, Monserrat-Vila, S, López-Pousa, S (2014). Dependence scale for Alzheimer’s disease relationship with other clinical indicators and psychometric properties. Journal of Geriatric Psychiatry and Neurology 28, 117125.
Health Information and Quality Authority (HIQA) (2016). Annual Overview Report on the Regulation of Designated Centres for Older People – 2015. Health Information and Quality Authority: Cork.
Helmer, C, Pérès, K, Letenneur, L, Guttiérez-Robledo, LM, Ramaroson, H, Barberger-Gateau, P, Fabrigoule, C, Orgogozo, J-M, Dartigues, J-F (2006). Dementia in subjects aged 75 years or over within the PAQUID cohort: prevalence and burden by severity. Dementia and Geriatric Cognitive Disorders 22, 8794.
Hofman, A, Rocca, WA, Brayne, C, Breteler, M, Clarke, M, Cooper, B, Copeland, J, Dartigues, J, Droux, ADS, Hagnell, O (1991). The prevalence of dementia in Europe: a collaborative study of 1980–1990 findings. International Journal of Epidemiology 20, 736748.
Kingston, A, Wohland, P, Wittenberg, R, Robinson, L, Brayne, C, Matthews, FE, Jagger, C (2017). Is late-life dependency increasing or not? A comparison of the Cognitive Function and Ageing Studies (CFAS). The Lancet 390, 16761684.
Lambert, M, Bickel, H, Prince, M, Fratiglioni, L, Von Strauss, E, Frydecka, D, Kiejna, A, Georges, J, Reynish, E (2014). Estimating the burden of early onset dementia; systematic review of disease prevalence. European Journal of Neurology 21, 563569.
Launer, L, Andersen, K, Dewey, M, Letenneur, L, Ott, A, Amaducci, L, Brayne, C, Copeland, J, Dartigues, J-F, Kragh-Sorensen, P (1999). Rates and risk factors for dementia and Alzheimer’s disease results from EURODEM pooled analyses. Neurology 52, 7878.
Manthorpe, J, Samsi, K, Campbell, S, Abley, C, Keady, J, Bond, J, Watts, S, Robinson, L, Gemski, A, Warner, J (2011). The transition from cognitive impairment to dementia: older people’s experiences. NIHR Service Delivery and Organisation Programme: Southampton.
Matthews, FE, Arthur, A, Barnes, LE, Bond, J, Jagger, C, Robinson, L, Brayne, C, the Medical Research Council Cognitive Function and Ageing Collaboration (2013). A two-decade comparison of prevalence of dementia in individuals aged 65 years and older from three geographical areas of England: results of the Cognitive Function and Ageing Study I and II. The Lancet 382, 14051412.
Matthews, FE, Bennett, H, Wittenberg, R, Jagger, C, Dening, T, Brayne, C (2016a). Who lives where and does it matter? Changes in the health profiles of older people living in long term care and the community over two decades in a high income country. PLoS One 11, e0161705.
Matthews, FE, Stephan, BCM, Robinson, L, Jagger, C, Barnes, LE, Arthur, A, Brayne, C, Cognitive Function and Ageing Studies Collaboration (2016b). A two decade dementia incidence comparison from the Cognitive Function and Ageing Studies I and II. Nat Commun, 7.
O’Connor, DW, Pollitt, P, Hyde, J, Fellows, J, Miller, N, Brook, C, Reiss, B, Roth, M (1989). The prevalence of dementia as measured by the Cambridge Mental Disorders of the Elderly Examination. Acta Psychiatrica Scandinavica 79, 190198.
O’Shea, E (2007). Implementing Policy for Dementia Care in Ireland: The Time for Action is Now. National University of Ireland, Galway: Galway.
O’Shea, E, Cahill, S, Pierce, M (2017). Developing and Implementing Dementia Policy in Ireland. NUI Galway: Galway.
Pierce, M, Cahill, S, O’Shea, E (2013). Planning dementia services: new estimates of current and future prevalence rates of dementia for Ireland. Irish Journal of Psychological Medicine 30, 1320.
Prince, M, Knapp, M, Guerchet, M, McCrone, P, Prina, M, Comas-Herrera, A, Wittenberg, R, Adelaja, B, Hu, B, King, D, Rehill, A, Salimkumar, D (2014). Dementia UK: Update, 2nd edn. Alzheimer’s Society UK: London.
Rocca, WA, Petersen, RC, Knopman, DS, Hebert, LE, Evans, DA, Hall, KS, Gao, S, Unverzagt, FW, Langa, KM, Larson, EB (2011). Trends in the incidence and prevalence of Alzheimer’s disease, dementia, and cognitive impairment in the United States. Alzheimer’s & Dementia 7, 8093.
Satizabal, CL, Beiser, AS, Chouraki, V, Chêne, G, Dufouil, C, Seshadri, S (2016). Incidence of dementia over three decades in the Framingham Heart Study. New England Journal of Medicine 374, 523532.
Schaller, S, Mauskopf, J, Kriza, C, Wahlster, P, Kolominsky-Rabas, PL (2015). The main cost drivers in dementia: a systematic review. International Journal of Geriatric Psychiatry 30, 111129.
Stokes, LA, Combes, H, Stokes, G (2014). Understanding the dementia diagnosis: the impact on the caregiving experience. Dementia 13, 5978.
Timmons, S, Manning, E, Barrett, A, Brady, NM, Browne, V, O’Shea, E, Molloy, DW, O’Regan, NA, Trawley, S, Cahill, S (2015). Dementia in older people admitted to hospital: a regional multi-hospital observational study of prevalence, associations and case recognition. Age and Ageing 44, 993999.
Toot, S, Swinson, T, Devine, M, Challis, D, Orrell, M (2016). Causes of nursing home placement for older people with dementia: a systematic review and meta-analysis. International Psychogeriatrics 29, 114.
Wu, Y-T, Fratiglioni, L, Matthews, FE, Lobo, A, Breteler, MM, Skoog, I, Brayne, C (2016). Dementia in western Europe: epidemiological evidence and implications for policy making. The Lancet Neurology 15, 116124.
Ziegler-Graham, K, Brookmeyer, R, Johnson, E, Arrighi, HM (2008). Worldwide variation in the doubling time of Alzheimer’s disease incidence rates. Alzheimer’s & Dementia 4, 316323.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Irish Journal of Psychological Medicine
  • ISSN: 0790-9667
  • EISSN: 2051-6967
  • URL: /core/journals/irish-journal-of-psychological-medicine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Type Description Title
Supplementary materials

Pierse et al. supplementary material
Table S1 and Figures S1-S2

 PDF (1.7 MB)
1.7 MB


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed