%0 Journal Article %J Ann Intern Med %D 2008 %T Prevalence of cognitive impairment without dementia in the United States. %A Brenda L Plassman %A Kenneth M. Langa %A Gwenith G Fisher %A Steven G Heeringa %A David R Weir %A Mary Beth Ofstedal %A James R Burke %A Michael D Hurd %A Guy G Potter %A Willard L Rodgers %A David C Steffens %A John J McArdle %A Robert J. Willis %A Robert B Wallace %K Aged %K Aged, 80 and over %K Cognition Disorders %K Dementia %K disease progression %K Humans %K Longitudinal Studies %K Prevalence %K United States %X

BACKGROUND: Cognitive impairment without dementia is associated with increased risk for disability, increased health care costs, and progression to dementia. There are no population-based prevalence estimates of this condition in the United States.

OBJECTIVE: To estimate the prevalence of cognitive impairment without dementia in the United States and determine longitudinal cognitive and mortality outcomes.

DESIGN: Longitudinal study from July 2001 to March 2005.

SETTING: In-home assessment for cognitive impairment.

PARTICIPANTS: Participants in ADAMS (Aging, Demographics, and Memory Study) who were age 71 years or older drawn from the nationally representative HRS (Health and Retirement Study). Of 1770 selected individuals, 856 completed initial assessment, and of 241 selected individuals, 180 completed 16- to 18-month follow-up assessment.

MEASUREMENTS: Assessments, including neuropsychological testing, neurologic examination, and clinical and medical history, were used to assign a diagnosis of normal cognition, cognitive impairment without dementia, or dementia. National prevalence rates were estimated by using a population-weighted sample.

RESULTS: In 2002, an estimated 5.4 million people (22.2%) in the United States age 71 years or older had cognitive impairment without dementia. Prominent subtypes included prodromal Alzheimer disease (8.2%) and cerebrovascular disease (5.7%). Among participants who completed follow-up assessments, 11.7% with cognitive impairment without dementia progressed to dementia annually, whereas those with subtypes of prodromal Alzheimer disease and stroke progressed at annual rates of 17% to 20%. The annual death rate was 8% among those with cognitive impairment without dementia and almost 15% among those with cognitive impairment due to medical conditions.

LIMITATIONS: Only 56% of the nondeceased target sample completed the initial assessment. Population sampling weights were derived to adjust for at least some of the potential bias due to nonresponse and attrition.

CONCLUSION: Cognitive impairment without dementia is more prevalent in the United States than dementia, and its subtypes vary in prevalence and outcomes.

%B Ann Intern Med %I 148 %V 148 %P 427-34 %8 2008 Mar 18 %G eng %N 6 %L newpubs20080528_AnnIntMed.pdf %1 http://www.ncbi.nlm.nih.gov/pubmed/18347351?dopt=Abstract %2 PMC2670458 %4 Cognitive Functioning/Dementia/Health Risk/PREVALENCE %$ 18530 %R 10.7326/0003-4819-148-6-200803180-00005 %0 Journal Article %J Neuroepidemiology %D 2007 %T Prevalence of dementia in the United States: the aging, demographics, and memory study. %A Brenda L Plassman %A Kenneth M. Langa %A Gwenith G Fisher %A Steven G Heeringa %A David R Weir %A Mary Beth Ofstedal %A James R Burke %A Michael D Hurd %A Guy G Potter %A Willard L Rodgers %A David C Steffens %A Robert J. Willis %A Robert B Wallace %K Age Distribution %K Aged %K Aged, 80 and over %K Cohort Studies %K Dementia %K Female %K Geriatric Assessment %K Health Surveys %K Humans %K Logistic Models %K Male %K Prevalence %K Sex Distribution %K United States %X

AIM: To estimate the prevalence of Alzheimer's disease (AD) and other dementias in the USA using a nationally representative sample.

METHODS: The Aging, Demographics, and Memory Study sample was composed of 856 individuals aged 71 years and older from the nationally representative Health and Retirement Study (HRS) who were evaluated for dementia using a comprehensive in-home assessment. An expert consensus panel used this information to assign a diagnosis of normal cognition, cognitive impairment but not demented, or dementia (and dementia subtype). Using sampling weights derived from the HRS, we estimated the national prevalence of dementia, AD and vascular dementia by age and gender.

RESULTS: The prevalence of dementia among individuals aged 71 and older was 13.9%, comprising about 3.4 million individuals in the USA in 2002. The corresponding values for AD were 9.7% and 2.4 million individuals. Dementia prevalence increased with age, from 5.0% of those aged 71-79 years to 37.4% of those aged 90 and older.

CONCLUSIONS: Dementia prevalence estimates from this first nationally representative population-based study of dementia in the USA to include subjects from all regions of the country can provide essential information for effective planning for the impending healthcare needs of the large and increasing number of individuals at risk for dementia as our population ages.

%B Neuroepidemiology %I 29 %V 29 %P 125-32 %8 2007 %G eng %N 1-2 %L newpubs20071203_ADAMSprevalence.pdf %1 http://www.ncbi.nlm.nih.gov/pubmed/17975326?dopt=Abstract %4 aging/Dementia/Epidemiology %$ 18200 %R 10.1159/000109998