Table 6. Selected Reports on occurrence (prevalence or incidence) of dementia and dementia subtypes¹ in the United States, by population setting, and study type.

Author	Dementia subtype(s)	Population / setting	Study type	Occurrence (prevalence or incidence)	Comment
Plassman [8], Langa [25]	Dementia, AD, VaD	Stratified random sample drawn from a nationally-representative cohort study (beginning in 1992) of persons born before 1954.	In-residence clinical assessment during 2001-2003 of participants aged ≥71 years for dementia with final diagnoses assigned by a consensus expert panel.	Prevalence in 2002 in those age ≥71 years: -Dementia: 13.9% (3.4 million) -AD: 9.7% (2.4 million) -VaD: 2.4% (0.6 million) Distribution of dementia subtypes: -AD: 69.9% -VaD: 17.4% -Other: 12.7%	Reported as the first population-based study of dementia to include persons from all regions of the United States and using a single standardized diagnostic protocol in a community-based sample [23]. By sex, prevalence increased by age for dementia, AD, and VaD.
Herbert [7],Bienias [22], Evans [24]	AD	Household residents over age 65 years in a geographically-defined biracial neighborhood of the south side of Chicago.	In-home clinical evaluation for AD of a stratified random sample of participants in longitudinal, population-based study of chronic health problems during 1993-2011, with U.S. prevalence estimates then developed using incidence rates from the Chicago sample, U.S. mortality, education, and U.S. Census Bureau population estimates.	Number of persons age >65 years in U.S. with AD in 2013: 5.0 million	National-level prevalence projections based on incidence estimates using persons residing in a single urban area, and assumed no incident dementia under age 65 years. Also assumed risk of dementia same for persons of Hispanic origin and the racial group with which they identify.
Savica [10]	DLB, PDD	Geographically-defined total population of Olmsted County, Minnesota, for the period 1991-2005.	Medical records linkage system was used to identify all persons who developed DLB or PDD; diagnosis confirmed through review of complete medical records by a movement disorders specialist.	Among persons in Olmsted County: -DLB incidence: 3.5 per 100,000 person-years overall, increasing with age and higher in men -PDD incidence: 2.5 per 100,000 person-years overall, increasing with age -Combined incidence: 5.9 per 100,000 person-years overall, increasing with age and higher in men	Noted by authors that both dementia subtypes share the same neuropathology and are difficult to differentiate at autopsy.
Knopman [9]	FTLD	5 prevalence studies (4 from Western Europe and 1 from Japan) and 3 incidence studies (1 from United States and 2 from Western Europe).	To estimate the prevalence of cases of the cognitive syndromes of FTLD (CS-FTLD, including behavioral variant frontotemporal dementia [bvFTD] or primary progressive aphasia [PPA]) in the United States in 2010,the authors used data from prevalence and incidence studies of FTLD and 7 studies of survival in FTLD	Estimated number of cases CS-FTLD: 20,000 – 30,000, with 10% under age 45 years and 30% over age 64 years.

¹Alzheimer's disease: AD; dementia with Lewy bodies: DLB; Parkinson disease dementia: PDD; Frontotemporal lobar degenerations: FTLD; vascular dementia: VaD