Prevalence Rates Of Dementia Research Articles

Age-specific and sex-specific prevalence and incidence of mild cognitive impairment, dementia, and Alzheimer dementia in blacks and whites: a report from the Einstein Aging Study.

As the population ages, the need to characterize rates of cognitive impairment and dementia within demographic groups defined by age, sex, and race becomes increasingly important. There are limited data available on the prevalence and incidence of amnestic mild cognitive impairment (aMCI) and nonamnestic mild cognitive impairment (naMCI) from population-based studies. The Einstein Aging Study, a systematically recruited community-based cohort of 1944 adults aged 70 or older (1168 dementia free at baseline; mean age, 78.8 y; average follow-up, 3.9 y), provides the opportunity to examine the prevalence and incidence rates for dementia, Alzheimer dementia (AD), aMCI, and naMCI by demographic characteristics. Dementia prevalence was 6.5% (4.9% AD). Overall dementia incidence was 2.9/100 person-years (2.3/100 person-years for AD). Dementia and AD rates increased with age but did not differ by sex. Prevalence of aMCI was 11.6%, and naMCI prevalence was 9.9%. aMCI incidence was 3.8 and naMCI incidence was 3.9/100 person-years. Rates of aMCI increased significantly with age in men and in blacks; sex, education, and race were not significant risk factors. In contrast, naMCI incidence did not increase with age; however, blacks were at higher risk compared with whites, even when controlling for sex and education. Results highlight the public health significance of preclinical cognitive disease.

Prevalence of Dementia in Al Kharga District, New Valley Governorate, Egypt

Background: With aging, there is a parallel increase in the prevalence of dementia worldwide. The aim of this work is to determine the prevalence of dementia among the population of Al Kharga District, New Valley, Egypt. Methods: Screening of all subjects aged ≥50 years (n = 8,173 out of 62,583 inhabitants) was done through a door-to-door survey by 3 neurologists, using a short standardized Arabic screening test and a modified Mini-Mental State Examination. Suspected cases were subjected to full clinical examination, psychometric assessment using the Cognitive Abilities Screening Instrument, Instrumental Activities of Daily Living Scale, Geriatric Depression Scale, Hachinski Ischemic Score, DSM-IV-TR diagnostic criteria, neuroimaging, and laboratory investigations, when indicated. Results: The prevalence rate of dementia was 2.26% for the population aged ≥50 years. It increased steeply with age to a maximum of 18.48% for those aged ≥80 years. Alzheimer’s disease (51.2%) was the most common subtype, followed by vascular dementia (28.7%), dementia due to general medical conditions (12.8%), and lastly dementia due to multiple etiologies (7.3%). Mild dementia was the commonest (53.7%). Conclusion: Dementia is prevalent in Egypt as elsewhere. Detection through a door-to-door surveyis the best method in developing countriesfor early detection of mild cases.

Trends in Alzheimer's Disease and Dementia in the Asian-Pacific Region

Dementia is an age associated illness with a devastating impact on patients and their families. In the USA, the broader society impact of dementia continues to be overwhelming, due largely to the huge health care and economic burden associated with the disease. Although the projected numbers of those affected, the economic, healthcare, and caregiver costs continue to have a place in US public policy, it is only recently that these issues are beginning to take a center stage in other regions in the world with their aging populations. It has been estimated that 35.6 million people are living with dementia worldwide—a number that is projected to increase to 65.7 million by 2030 and 115.4 million by 2050. Approximately, 60% of the worlds' population lives in the Asian Pacific region—a home to many different ethnic groups. This issue of the International Journal of Alzheimer's Disease is dedicated to dementia in the Asian and Pacific region and discusses from an Asian-Pacific perspective common themes often noted in the literature from Europe and North America. Themes discussed in this special issue include (1) the prevalence and incidence rates of dementia in Asian countries, (2) the role of biological and genetic risk factors to the development of dementia, (3) characterization of dementia in culturally diverse populations, and (4) activities of daily living functioning and its relation to cognitive functioning. In this issue, two studies examined the prevalence, incidence, and mortality rates of dementia. H. H. Dodge et al. examined changes in dementia prevalence and the relative prevalence of AD compared to VaD over time using eight large Japanese prevalence studies. Unlike past studies on this topic, the authors thoroughly examined diagnostic criteria used in each study (through contacting original investigators of the most studies), changing age structures as well as regional variability as possible explanations of trends in overall prevalence and ratios of AD to VaD. The study suggests that, in contrast to the USA and some European countries, all-cause dementia prevalence is increasing in Japan. It was inconclusive whether the prevalence of AD as opposed to VaD has been increasing or not, because of variability in diagnostic criteria, regional variability, and gender difference in vascular disease prevalence. This study illustrates the complexity of evaluating prevalence rates of dementia and how knowledge of population trends in risk factors and diagnostic methods influences the interpretation of data. In addition, the authors offer useful suggestions for future epidemiological work on dementia prevalence and incidence in Japan which may be applied to other countries. In another article, the prevalence rates and mortality of dementia was examined in elderly persons living in Hong Kong. This study suggests that within 30 years the number of people in Hong Kong aged 60 and older will be more than triple; thus, the increase of prevalence of dementia cases in this region will prove to be substantial. The authors also discuss two other important issues related to care for those with dementia: (1) the impact of a declining “oldest old support ratio” and (2) the burden of dementia as measured by the Disability Adjusted Life Years (DALYs) approach. The authors postulate that by using these two metrics, in addition to data regarding the ongoing trends in the region, a successfully long-term care strategy for dementia of the aging population in Hong Kong can be achieved.

Factors Associated With Increased Risk for Dementia in Individuals Age 80 Years or Older With Congestive Heart Failure

An increasing body of evidence shows that individuals diagnosed with congestive heart failure (CHF) are at a higher risk for dementia. However, the prevalence rate of dementia among persons with CHF in very old individuals has not been previously reported, and little is known about the comorbidities that place old persons with CHF at a higher risk for dementia. The aim of this study was to compare the prevalence of dementia in individuals 80 years or older who have CHF with that in individuals without CHF and to identify factors related to dementia in individuals diagnosed with CHF. A total of 702 participants from a Swedish population-based longitudinal study (Octogenerian Twin) were included. The group consisted of same-sex twin pairs, age 80 years or older, and 138 participants had CHF. Dementia was diagnosed according to criteria in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised. Generalized estimating equations including gender, age and educational level, waist circumference, diabetes, hypertension, smoking, depression, and blood values were used in a case-control analysis. Individuals with CHF had a significantly higher prevalence of vascular dementia, 16% vs 6% (P < 0.001), and of all types of dementia, 40% vs 30% (P < 0.01), than those not diagnosed with CHF. The generalized estimating equation models showed that depression, hypertension, and/or increased levels of homocysteine were all associated with a higher risk for dementia in individuals with CHF. Diabetes was specifically associated with an increased risk for vascular dementia. The prevalence of dementia was higher among individuals with CHF than in those without CHF. Diabetes, depression, and hypertension in patients with CHF require special attention from healthcare professionals because these conditions are associated with an elevated risk for dementia. Higher levels of homocysteine were also found to be a marker of dementia in patients with CHF. Further research is needed to identify the factors related to dementia in individuals 80 years or older diagnosed with CHF.

Trends in Prevalence and Mortality of Dementia in Elderly Hong Kong Population: Projections, Disease Burden, and Implications for Long-Term Care

Background. We describe the trends in prevalence and mortality of dementia among older people in Hong Kong over time. Projections of the number of older people with dementia through 2039 and estimation of the disease burden are also included. Methods. Prevalence data were extracted from previous studies in Hong Kong. Mortality data were obtained from the Department of Health of Hong Kong. Projections of the number of people with dementia were calculated by applying the prevalence rates of dementia obtained from previous studies to Hong Kong population projections. The burden of dementia was measured by Disability-Adjusted Life Years (DALYs). Results. The number of people aged 60 and above with dementia is projected to increase by 222%, from 103,433 in 2009 to 332,688 in 2039, with a large proportion of those living in institutions. The number of deaths due to dementia among people aged 60 and above has more than doubled between 2001 and 2009. Mortality rates for dementia have also risen. In 2006, about 286,313 DALYS were lost due to dementia. Conclusions. The information presented may be used to formulate a long-term care strategy for dementia of the ageing population in Hong Kong.

Diagnostic Validity of Age and Education Corrections for the Mini‐Mental State Examination in Older African Americans

To investigate whether demographic (age and education) adjustments for the Mini-Mental State Examination (MMSE) attenuate mean score discrepancies between African-American and Caucasian adults and whether demographically adjusted MMSE scores improve the diagnostic classification accuracy of dementia in African-American adults over unadjusted MMSE scores. Cross-sectional study. Community-dwelling adults participating in the Mayo Clinic Alzheimer's Disease Patient Registry and Alzheimer's Disease Research Center. Three thousand two hundred fifty-four adults (2,819 Caucasian, 435 African American) aged 60 and older. MMSE score at study entry. African-American adults had significantly lower unadjusted MMSE scores (23.0±7.4) than Caucasian adults (25.3±5.4). This discrepancy persisted despite adjustment of MMSE scores for age and years of education using established regression weights or newly derived weights. Controlling for dementia severity at baseline and adjusting MMSE scores for age and quality of education attenuated this discrepancy. In African-American adults, an age- and education-adjusted MMSE cut score of 23/24 provided optimal dementia classification accuracy, but this represented only a modest improvement over an unadjusted MMSE cut score of 22/23. The posterior probability of dementia in African-American adults is presented for various unadjusted MMSE cut scores and prevalence rates of dementia. Age, dementia severity at study entry, and quality of educational experience are important explanatory factors in understanding the existing discrepancies in MMSE performance between Caucasian and African-American adults. These findings support the use of unadjusted MMSE scores when screening older African Americans for dementia, with an unadjusted MMSE cut score of 22/23 yielding optimal classification accuracy.

Prevalence and Incidence Rates of Dementia and Cognitive Impairment No Dementia in the Mexican Population

To estimate the prevalence and incidence of dementia and cognitive impairment without dementia (CIND) in the Mexican population. The MHAS study is a prospective panel study of health and aging in Mexico with 7,000 elders that represent eight million participants nationally. Using measurements of cognition and activities of daily living of dementia cases and CIND were identified at baseline and follow-up. Overall incidence rates and specific rates for sex, age, and education were calculated. Prevalence was 6.1% and 28.7% for dementia and CIND, respectively. Incidence rates were 27.3 per 1,000 person-years for dementia and 223 per 1,000 persons-year for CIND. Rates of dementia and CIND increased with advancing age and decreased with higher educational level; sex had a differential effect depending on the age strata. Hypertension, diabetes, and depression were risk factors for dementia but not for CIND. These data provide estimates of prevalence and incidence of dementia and cognitive impairment in the Mexican population for projection of future burden.

Dementia in Chinese populations: Current data and future research

AbstractThis review summarizes the literature on the prevalence and incidence rates of dementia in Chinese populations, including survey results outside mainland China. We identified 15 prevalence studies and five incidence studies. The studies consistently reported sharply increased prevalence and incidence rates of dementia with increasing age. As estimated, there are at least 6,464,040 dementia patients in mainland China alone and we expect the number to rise in the coming decades. It is clear that dementia will be a new epidemic of the 21st century without major public health policies and preventive measures that target at the disease. We urge more research and hope that we will be able to prevent dementia or at least delay the onset in the near future with evidence‐based measures.

Prevalence and incidence of dementia among 75–80-year-old community-dwelling elderly in different districts of Antwerp, Belgium: The Antwerp Cognition (ANCOG) Study

Objective To analyse the prevalence and incidence of dementia in a population of community-dwelling elderly (aged 75–80), living in socio-economically differing districts of Antwerp (Belgium), taking into account possible gender and educational differences. Methods A longitudinal cohort study ( N = 825) with a 3-year follow-up period ( N = 363). The Mini Mental State Examination (MMSE) was used as a primary screen of cognitive functioning. Scoring 21 or below led to a second phase examination by a neurologist, including the CAMDEX-R-N and a neurological examination, to provide a tentative aetiological diagnosis of dementia. These procedures were conducted annually during a 3-year follow-up period. Results In accordance with international literature, the overall prevalence rate of dementia was 8.7%. The cumulative incidence rate (IR) of dementia was 36.60 per 1000 Py with annual IRs ranging from 34.39 over 35.16 to 49.04 per 1000 Py. Dementia of the Alzheimer type (DAT) was the most occurring prevalent and incident cause. Women appeared to be at higher risk and the occurrence of cognitive deterioration was more prominent in districts with lower socio-economic status, possibly related to a lower education level. Conclusion We demonstrate dementia is a considerable health problem in an urban Belgian population of community-dwelling elderly aged between 75 and 80 years old. In order to prepare health care and social security systems for the future management of dementia, proper epidemiological insight into the current and future magnitude of the burden of dementia, taking into account socio-economic differences, to which this study contributes, are required.

Epidemiological features of chronic and Alzheimer's diseases in the community-based elderly living in cities and counties in Hebei province

To understand the epidemiological features of Alzheimer's disease (AD) in the community-based elderly living in cities and counties in Hebei province. Under the stratified random sampling method, Mini Mental State Examination (MMSE) was used to evaluate senile dementia and Activity of Daily Living Scale (ADL) and to evaluate the daily lives of the elderly. Related dementia standard on the diagnose of AD and its subtypes was used. Statistically, data was analyzed through SPSS 13.0 software. The overall prevalence was 64.84% (2355/3632) on chronic diseases in those elderly who were over 60 years of age while AD appeared to be high and increased with age. The prevalence rate of dementia was 7.24% (263/3632), in which AD accounted for 4.87% (177/3632). Rates for other chronic diseases were as follows:hypertension (32.35%), diabetes (11.37%), chronic obstructive pulmonary disease (9.25%), coronary heart disease (8.84%) and stroke (7.16%). The prevalence of AD increased with age and was related to the low degree of education having. Elderly living in the communities of Hebei province showed high prevalent rates of chronic diseases including AD, which had become the major kind of diseases related to old age.

The use of the Digit Span Test in screening for cognitive impairment in acute medical inpatients

There is no valid instrument currently in use at acute-care hospitals in Hong Kong to aid the detection of cognitive impairment. The objectives of this study were to (1) validate the Digit Span Test (DST) in the identification and differentiation of dementia and delirium; and (2) determine the prevalence of major cognitive impairment in elderly people in an acute medical unit. During the study period from January to February 2010, 144 patients aged 75 years or more who had had unplanned medical admissions were assessed by nurses, using the Digit Span Forwards (DSF) and the Digit Span Backwards (DSB) tests. The DST scores were compared with the psychiatrists' DSM-IV-based diagnoses. Receiver Operating Characteristics curve (ROC) was used in conjunction with sensitivity and specificity measures to assess the performance of DST. The prevalence rates of dementia alone, delirium alone and delirium superimposed on dementia were 21.5%, 9% and 9% respectively. The prior case-note documentation rate was 13.2% for dementia and 2.8% for delirium. Regarding the detection of major cognitive impairment, the ROC curve of DSB showed a sensitivity of 0.77 and specificity of 0.78 at the optimal cutoff of <3. A significant association between scores on the DST and the Cantonese version of the Mini-Mental State Examination (CMMSE) was found in this study (p < 0.05 for DSF, p = 0.00 for DSB). Dementia and delirium were prevalent, yet under-recognized, in acute medical geriatric inpatients. The DSB is an effective tool in identifying patients with major cognitive impairment.

Psychological trauma and fear for personal safety as a result of behaviours that challenge in dementia: The experiences of healthcare workers

Few studies have systematically documented the psychological effects of exposure to aggression on healthcare workers. In 2007 an exploratory study invited 96 nurses and 228 care assistants from nine care homes to complete a questionnaire that incorporated the Impact Events Score — Extended (IES-E). Of the 112 returned (response rate 34.56%), 77 (68.8%) staff had been involved in an incident where they feared for their personal safety and 80 (71.4%) witnessed an incident where they feared for the safety of a colleague. Over the previous year 34% felt ‘very unsafe’ and almost 18% felt ‘terrified’. Violence against care home staff are not isolated incidents and irrespective of length of time working in dementia care staff lack the skills to identify triggers factors or appreciate the role they play in activating aggression. Their reluctance to engage with aggressive residents compromises care. An increasing ageing population combined with prevalence rates for dementia will place greater demands on care homes. Nationally agreed accredited qualifications for care assistants based on knowledge, and skills and attitudes specific to dementia care, may raise the standard of care. Infrastructures to support assaulted staff may reduce feelings of isolation, assist with recruitment and retention problems and provide social support.

Epidemiological studies of cognitive impairment and dementia across Eastern and Middle European countries (epidemiology of dementia in Eastern and Middle European Countries)

To determine the availability and the consistency of prevalence findings of epidemiological studies on cognitive impairment and dementia conducted in Eastern and Middle Europe. We adopted a stepwise multimethod study approach consisting of iterative literature searches for epidemiological articles published between 1990 and 2006 and subsequent data analyses of published material, reanalyses of existing accessible epidemiological data sets and expert inquiries in Eastern and Middle European countries. Systematic computer-assisted searches used the keywords: "dementia", "Alzheimer", "cognitive impairment", "incidence", "prevalence", "epidemiology" in combination with the name of the relevant countries or "Europe" in English and Polish language. We supplemented the literature search with a review of the references in the articles that were identified during the initial search. We were able to find few regional and country-specific epidemiological studies of various kinds (population-based, cohort, cross-sectional studies) and conducted on different restricted population groups of patients (from neurological units, out-patients units, residential homes). No studies were identified from most of the countries taken under consideration and the ones we found were characterized by an immense diversity with a considerable degree of clinical and methodological variations. The few studies that there are suggest prevalence rates of dementia in Eastern Europe similar to those in Western Europe. There is strong need for epidemiological studies in Eastern and Middle Europe, as well as for greater coordination and standardization of methods to improve the quality and comparability of epidemiological data to determine the prevalences' rates of dementia in all the EU countries.

Sociodemographic Risk Factors and Correlates of Dementia in Older Malaysians

Objective: The rapid expansion of the aged population in Malaysia is expected to greatly increase the number of persons with dementia in the country. However, data on dementia prevalence at the national level is lacking, and little is known about the sociodemographic risk factors and correlates of dementia. This paper describes a nationwide study of dementia prevalence and its sociodemographic risk factors and health correlates among older Malaysians. Methods: In the nationwide study, the Mental Health and Quality of Life of Older Malaysians, AGECAT-GMS was used to diagnose dementia in a nationally representative sample of 2,980 persons aged 60 and above. Results: The prevalence rate of dementia was 14.3%. Higher dementia prevalences were found in oldest age (26.3%), women (19.7%), no formal education (24.1%), Bumiputeras (32.2%), unmarried (19.4%), unemployed (31.3%) and very poor on self-rated health (33.3%). Multivariate logistic regression analyses showed that older age, female gender, no formal education, ethnicity and very poor self-rated health were independent risk factors and correlates of dementia. Conclusions: Relatively higher prevalence rates of dementia in older Malaysians were accounted for by greater proportions without education, Malay and Bumiputera ethnicity, and other unknown factors which should be further investigated.

Trends in the incidence and prevalence of Alzheimer’s disease, dementia, and cognitive impairment in the United States

Declines in heart disease and stroke mortality rates are conventionally attributed to reductions in cigarette smoking, recognition and treatment of hypertension and diabetes, effective medications to improve serum lipid levels and to reduce clot formation, and general lifestyle improvements. Recent evidence implicates these and other cerebrovascular factors in the development of a substantial proportion of dementia cases. Analyses were undertaken to determine whether corresponding declines in age-specific prevalence and incidence rates for dementia and cognitive impairment have occurred in recent years. Data spanning 1 or 2 decades were examined from community-based epidemiological studies in Minnesota, Illinois, and Indiana, and from the Health and Retirement Study, which is a national survey. Although some decline was observed in the Minnesota cohort, no statistically significant trends were apparent in the community studies. A significant reduction in cognitive impairment measured by neuropsychological testing was identified in the national survey. Cautious optimism appears justified.

Over‐ and under‐diagnosis of dementia in ethnic minorities: a nationwide register‐based study

Among dementia professionals in several European countries, it is believed that dementia is under-diagnosed and under-treated to a greater extent among ethnic minorities than in the native population. It is unknown whether this belief holds true. The objective of this study was to compare the prevalence of register-based dementia diagnoses in the largest ethnic minority groups in Denmark with the prevalence of register-based dementia diagnoses in the general Danish population. By linking the Danish hospital registers with the Danish Civil Registration System, nationwide dementia cases for three main ethnic minorities were identified. Age- and gender-specific prevalence rates for dementia were calculated and compared to previously published data for the general population. The study population consisted of 68 219 persons aged 20 and older. A total of 174 dementia cases were identified. The mean age at diagnosis was 57.7 years (SD = 16.2). Compared to the general population, there was a higher prevalence of dementia among those younger than 60 years, and a markedly lower prevalence of dementia among those 60 years and older. Dementia is under-diagnosed to a greater extent among ethnic minorities in the age group 60 years and older but is over-diagnosed in the age group younger than 60 years. Several factors may contribute to this pattern, including cultural differences in help-seeking behaviour, and problems in navigating the health-care system. Furthermore, cross-cultural assessment of dementia can be difficult because of language barriers and cultural differences.

Prevalence of dementia and dementia subtypes among community-dwelling elderly people in northern Nigeria

Dementia has important public health implications. The magnitude of the problem remains largely unknown in the developing countries. Three hundred and twenty-two community dwelling elderly persons and their caregivers in Zaria, Northern-Nigeria were enrolled in this study. They were interviewed using Community Screening Interview for Dementia (CSI-D), Consortium to Establish Registry for Alzheimer's disease (CERAD), Stick Design Test (SDT), Blessed Dementia Scale and a sociodemographic questionnaire. The data obtained were analyzed using the Statistical Package for Social Sciences version 15 for Windows. Diagnosis was based on fulfilling criteria for dementia in both the International Classification of Disease, 10th edition and the Diagnostic and Statistical Manual, 4th edition. The mean age of the subjects was 75.5 ± 9.4 years. The prevalence of dementia was 2.79% (CI 1-4.58%). Alzheimer's disease constituted 66.67% of all the cases of dementia in this community. Age was the only demographic factor associated with dementia. The prevalence rates of dementia and dementia subtypes in the developing countries are similar using standard diagnostic criteria and methods.

Dementia in Older Adults With Intellectual Disabilities-Epidemiology, Presentation, and Diagnosis

As life expectancy of people with intellectual disabilities (ID) extends into older age, dementia is an increasing cause of morbidity and mortality. To update and summarize current knowledge on dementia in older adults with ID, the authors conducted a comprehensive review of the published literature from 1997–2008 with a specific focus on: (1) epidemiology of dementia in ID in general as well as in specific genetic syndromes; (2) presentation; and (3) diagnostic criteria for dementia. The review drew upon a combination of searches in electronic databases Medline, EMBASE, and PsycINFO for original research papers in English, Dutch, or German. The authors report that varied methodologies and inherent challenges in diagnosis yield a wide range of reported prevalence rates of dementia. Rates of dementia in the population with intellectual disability not because of Down syndrome (DS) are comparable with or higher than the general population. Alzheimer's disease onset in DS appears earlier and the prevalence increases from under 10% in the 40s to more than 30% in the 50s, with varying prevalence reported for those 60 and older. Incidence rates increase with age. Few studies of dementia in other genetic syndromes were identified. Presentation differs in the ID population compared with the general population; those with DS present with prominent behavioral changes believed to be because of frontal lobe deficits. Authors recommend large-scale collaborative studies of high quality to further knowledge on the epidemiology and clinical presentation of dementia in this population.

Prevalence of Dementia in Puerto Rican Veterans is Higher than in Mainland U.S. Veterans

Prevalence of Dementia in Puerto Rican Veterans is Higher than in Mainland U.S. Veterans

Pro12Ala polymorphism in PPAR-γ2 and dementia in Chinese nonagenarians/centenarians

We examined the existence of a relationship between polymorphism and dementia in subjects aged 90 years and above. The sample included 732 unrelated Chinese nonagenarians/centenarians (aged 90-108 years, mean age 93.68 years; 67.5% women). The Pro12Ala variant was examined using polymerase chain reaction restriction fragment length polymorphism. Cognitive function was measured with 30-item mini-mental state examination. The genotype frequencies of the Pro12Ala polymorphism were 0% Ala12Ala, 9.1% Pro12Ala, and 90.9% Pro12Pro. The prevalence rates of dementia were 64.9% in the whole sample (45.0% for men and 74.5% for women). In both men and women, between subjects with and without 12Ala carriers, there was no significant difference in cognitive function scores and also no significant difference in prevalence of dementia; there was no significant difference in frequency of 12Ala carriers between subjects with and without dementia. Multiple logistic regression was performed by adjusting clinical factors that are thought to be associated with cognitive function or with 12Ala carriers. We found that 12Ala is not a risk factor for dementia. We found that Pro12Ala polymorphism in PPAR-gamma2 was not directly correlated with dementia among Chinese nonagenarians and centenarians.