There are inconsistent findings with respect to the prevalence of DLB. Much depends on case ascertainment methods, which have changed over time, and the orientation and awareness of clinicians making the diagnoses with respect to DLB.
It is estimated that 57.4 million people were living with dementia globally in 2019.[5]GBD 2019 Dementia Forecasting Collaborators. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. Lancet Public Health. 2022 Feb;7(2):e105-25.
https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(21)00249-8/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/34998485?tool=bestpractice.com
The prevalence of DLB is probably around 10% to 15% of all cases of dementia.[6]Expert Panel on Neurological Imaging; Moonis G, Subramaniam RM, Trofimova A, et al. ACR Appropriateness Criteria® dementia. J Am Coll Radiol. 2020 May;17(5s):S100-12.
https://www.jacr.org/article/S1546-1440(20)30128-9/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/32370954?tool=bestpractice.com
DLB may be more likely to present as a nonamnestic form of mild cognitive impairment (MCI), while amnestic MCI is more likely in Alzheimer disease (AD).[2]Hemminghyth MS, Chwiszczuk LJ, Rongve A, et al. The cognitive profile of mild cognitive impairment due to dementia with Lewy bodies - an updated review. Front Aging Neurosci. 2020 Dec 23;12:597579.
https://www.frontiersin.org/articles/10.3389/fnagi.2020.597579/full
http://www.ncbi.nlm.nih.gov/pubmed/33424578?tool=bestpractice.com
[7]Ferman TJ, Smith GE, Kantarci K, et al. Nonamnestic mild cognitive impairment progresses to dementia with Lewy bodies. Neurology. 2013 Dec 3;81(23):2032-8.
http://www.ncbi.nlm.nih.gov/pubmed/24212390?tool=bestpractice.com
DLB is probably overrepresented in clinics that have a particular interest in neuropsychiatric disorders (due to psychosis being an indication for such referral). Mixed dementia pathology is common, with up to 50% of patients with AD having unsuspected Lewy-related pathology at autopsy.[1]McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: fourth consensus report of the DLB Consortium. Neurology. 2017 Jul 4;89(1):88-100.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496518
http://www.ncbi.nlm.nih.gov/pubmed/28592453?tool=bestpractice.com
The most recent consensus is that the 1-year rule in terms of cognitive symptoms preceding motor dysfunction is useful in distinguishing DLB from Parkinson disease-related neurocognitive disorder.[1]McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: fourth consensus report of the DLB Consortium. Neurology. 2017 Jul 4;89(1):88-100.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496518
http://www.ncbi.nlm.nih.gov/pubmed/28592453?tool=bestpractice.com
Incidence of DLB is approximately 0.1% per year for the general population. There is some evidence that prevalence is positively correlated with increasing age.[8]Zaccai J, McCracken C, Brayne C. A systematic review of prevalence and incidence studies of dementia with Lewy bodies. Age Ageing. 2005 Nov;34(6):561-6.
http://ageing.oxfordjournals.org/content/34/6/561.full
http://www.ncbi.nlm.nih.gov/pubmed/16267179?tool=bestpractice.com
Literature on other specific risk factors is limited. There is no consensus on whether there are any sex differences in prevalence; studies have reported both male and female preponderance.[9]Podcasy JL, Epperson CN. Considering sex and gender in Alzheimer disease and other dementias. Dialogues Clin Neurosci. 2016 Dec;18(4):437-46.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5286729
http://www.ncbi.nlm.nih.gov/pubmed/28179815?tool=bestpractice.com
[10]Mouton A, Blanc F, Gros A, et al. Sex ratio in dementia with Lewy bodies balanced between Alzheimer's disease and Parkinson's disease dementia: a cross-sectional study. Alzheimers Res Ther. 2018 Sep 12;10(1):92.
https://alzres.biomedcentral.com/articles/10.1186/s13195-018-0417-4
http://www.ncbi.nlm.nih.gov/pubmed/30208961?tool=bestpractice.com
There are not thought to be significant ethnic or geographic differences in prevalence.[8]Zaccai J, McCracken C, Brayne C. A systematic review of prevalence and incidence studies of dementia with Lewy bodies. Age Ageing. 2005 Nov;34(6):561-6.
http://ageing.oxfordjournals.org/content/34/6/561.full
http://www.ncbi.nlm.nih.gov/pubmed/16267179?tool=bestpractice.com