Lui VW, Lam LC, Luk DN, Wong LH, Tam CW, Chiu HF, Appelbaum PS. Capacity to make treatment decisions in Chinese older persons with very mild dementia and mild Alzheimer disease. Am J Geriatr Psychiatry. 2009 May;17(5):428-36.

OBJECTIVES: This study aims at assessing mental competence in Chinese patients with mild and very mild dementia with a semistructured assessment method and the impact of repeated presentations of information on patients' mental competence. DESIGN: Subjects with mild and very mild dementia were compared with cognitively intact subjects. SETTING: Chinese subjects were recruited from local social centers and residential hostels for the elderly in Hong Kong. PARTICIPANTS: Sixty-six Chinese community-dwelling older adults (aged from 65 to 87 years) were recruited. MEASUREMENTS: Clinical diagnosis was made by experienced geriatric psychiatrists. Subjects were assessed with the Mini-Mental State Examination and the Clinical Dementia Rating (CDR). Mental capacity to consent to treatment was assessed by using the Chinese version of the MacArthur Competence Assessment Tool-Treatment (MacCAT-T) and independent clinician ratings based on the definition in the Mental Capacity Act 2005 of the United Kingdom. RESULTS: Thirty-three (50%) participants were diagnosed with very mild or mild dementia (CDR = 0.5 or 1). In this group, 15 (45.5%) subjects were rated as mentally incompetent in clinician ratings. In the assessment of interrater reliability, the intraclass correlation coefficient of MacCAT-T summary scores among three raters ranged from 0.64 to 0.83. The MacCAT-T summary scores correlated significantly with clinician ratings, years of education, Mini-Mental State Examination score, and CDR. In contrast to the nonimpaired group, repeated presentation of information did not significantly improve capacity in the demented group. CONCLUSION: Results from this study suggest that even patients with very mild dementia in this population can show substantial deficits in decision-making capacity, and that improved capacity is not likely to result from repeated disclosure of information.

Dong MJ, Peng B, Lin XT, Zhao J, Zhou YR, Wang RH. The prevalence of dementia in the People's Republic of China: a systematic analysis of 1980-2004 studies. Age Ageing. 2007 Nov;36(6):619-24.

BACKGROUND: Dementia has been a major public health problem. However, there has not yet been a nationwide investigation or systematic analysis of the prevalence of dementia in China from 1980 to 2004. OBJECTIVES: The aim of this study was to analyse the prevalence of dementia and its major subtypes [Alzheimer disease (AD), vascular dementia (VD)] among the population aged 60 years and older in China from 1980 to 2004. METHODS: Epidemiological investigations on dementia in China published in journals and covering the period from 1980 to 2004 were identified manually and on-line by using CBMDISK, Chongqing VIP database and CNKI database. Those reported in English journals were identified using MEDLINE. Selected studies had to describe an original study defined by strict screening and diagnostic criteria. The fixed effects model or random effects model was employed according to statistical test for homogeneity. RESULTS: Twenty-five studies were selected, the statistical information of which was collected for systematic analysis. Our results showed that AD and VD were the two major subtypes of dementia in China, and the pooled prevalence of AD and VD for the population aged 60 years and older was 1.6 and 0.8%, respectively. There was a higher prevalence of AD in the illiterate elderly population (3.2%) than in those who received years of education. The chronological prevalence of AD increased significantly from 1980 to 2004. In southern and northern China, the prevalence of AD was 2.0 and 1.2%, respectively, while VD was 0.6 and 1.1%, respectively. CONCLUSIONS: In the last 24 years, AD and VD were the two major subtypes of dementia in China. The prevalence of AD may be affected by sex, education, occupation or age. The prevalence of VD, which was higher in northern than in southern China, seems not to be affected by age, sex or education.

Zhou DF, Wu CS, Qi H, Fan JH, Sun XD, Como P, Qiao YL, Zhang L, Kieburtz K. Prevalence of dementia in rural China: impact of age, gender and education. Acta Neurol Scand. 2006 Oct;114(4):273-80.

OBJECTIVE: To determine the prevalence of dementia and Alzheimer's disease (AD) in rural China. METHODS: A cross-sectional study was conducted within a cohort of adults older than 50 years of age in Linxian County, China. A Chinese version of the Mini-Mental State Examination (CMMSE) was used to screen cases of possible dementia. Three different cutoff points on CMMSE were applied depending on the participant's level of education. The participants then were given psychiatric interviews, medical and neurological examinations, and psychometric tests to ascertain the clinical diagnoses of dementia and AD. RESULTS: Among the 16,095 participants, 5.26% were screened positive with 374 diagnosed as having dementia. Among them, AD accounted for 80.5%. The adjusted prevalence rates were 0.33%, 0.89%, 3.43%, and 8.19% in people in age groups 50-54, 55-64, 65-74, and 75 and above, respectively. The prevalence of AD correlated with the participant's level of education, and was 2.61%, 0.94%, and 0.56% in the illiterate group, in the primary school group, and in the middle school or higher group, respectively. Adjusted by education levels a higher prevalence in women was observed in the illiterate group. CONCLUSIONS: The prevalence of dementia in this population is similar to that reported from other areas in mainland China and Taiwan with aging being a significant risk factor. After controlling for age, being a female and having received less number of years of education were associated with an higher prevalence of AD.

Ferri CP, Prince M, Brayne C, Brodaty H, Fratiglioni L, Ganguli M, Hall K, Hasegawa K, Hendrie H, Huang Y, Jorm A, Mathers C, Menezes PR, Rimmer E, Scazufca M; Alzheimer's Disease International. Global prevalence of dementia: a Delphi consensus study. Lancet. 2005 Dec 17;366(9503):2112-7.

BACKGROUND: 100 years after the first description, Alzheimer's disease is one of the most disabling and burdensome health conditions worldwide. We used the Delphi consensus method to determine dementia prevalence for each world region. METHODS: 12 international experts were provided with a systematic review of published studies on dementia and were asked to provide prevalence estimates for every WHO world region, for men and women combined, in 5-year age bands from 60 to 84 years, and for those aged 85 years and older. UN population estimates and projections were used to estimate numbers of people with dementia in 2001, 2020, and 2040. We estimated incidence rates from prevalence, remission, and mortality. FINDINGS: Evidence from well-planned, representative epidemiological surveys is scarce in many regions. We estimate that 24.3 million people have dementia today, with 4.6 million new cases of dementia every year (one new case every 7 seconds). The number of people affected will double every 20 years to 81.1 million by 2040. Most people with dementia live in developing countries (60% in 2001, rising to 71% by 2040). Rates of increase are not uniform; numbers in developed countries are forecast to increase by 100% between 2001 and 2040, but by more than 300% in India, China, and their south Asian and western Pacific neighbours. INTERPRETATION: We believe that the detailed estimates in this paper constitute the best currently available basis for policymaking, planning, and allocation of health and welfare resources.

Zhang ZX, Zahner GE, Román GC, Liu J, Hong Z, Qu QM, Liu XH, Zhang XJ, Zhou B, Wu CB, Tang MN, Hong X, Li H. Dementia subtypes in China: prevalence in Beijing, Xian, Shanghai, and Chengdu. Arch Neurol. 2005 Mar;62(3):447-53.

BACKGROUND: Prevalences of Alzheimer disease (AD) and vascular dementia (VaD) in China reportedly differ from those in Western countries. OBJECTIVE: To estimate prevalence of AD and VaD in 4 regions of China. DESIGN: Cross-sectional, population-based prevalence survey with a stratified, multistage cluster sampling design. SETTING: Rural (n = 99) and urbanized (n = 71) communities of Beijing, Xian, Shanghai, and Chengdu. PARTICIPANTS: A sample of 34 807 community residents (94% of those eligible) 55 years or older. MAIN OUTCOME MEASURES: Participants were screened with the Chinese Mini-Mental State Examination. Those who screened positive (n = 3950) underwent a standardized diagnostic workup. Screening sensitivity was assessed in a 3.3% random sample (n = 1008 of the 30 857 who passed the screening). Diagnoses of AD and VaD were made according to National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer Disease and Related Disorders Association and National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences criteria, respectively. Final diagnoses were made after a 6-month confirmation interval. RESULTS: We identified 732 AD cases and 295 VaD cases. Prevalence in persons 65 years or older was 3.5% (95% confidence interval, 3.0%-3.9%) for AD and 1.1% (95% confidence interval, 0.9%-1.1%) for VaD. After post hoc correction for negative screening errors, prevalence increased to 4.8% for AD and remained at 1.1% for VaD. CONCLUSION: Prevalence of dementia subtypes in China is comparable with that in Western countries.

Wang W, Wu S, Cheng X, Dai H, Ross K, Du X, Yin W. Prevalence of Alzheimer's disease and other dementing disorders in an urban community of Beijing, China. Neuroepidemiology. 2000 Jul-Aug;19(4):194-200.

A door-to-door two-phase study was used to investigate the prevalence of senile dementia in an urban community of Beijing. In the study population, 5,003 individuals aged 60 years and older (>/=65 years, n = 3,728) were screened at home with the Chinese version of the MMSE. Persons who screened positive for dementia, using different cutoff scores based on degree of literacy, were further evaluated using the criteria of DSM-III-R and ICD-10. Among subjects who screened positive in phase I, 134 were diagnosed as having dementia in phase II. The prevalence ratios of dementia were 2.68% in the population aged 60 years and older, and 3.49% in the population aged 65 years and older. The prevalence rates among those aged 65 years and older were 1.85% for Alzheimer's disease, 1.37% for vascular dementia and 0.27% for other dementia (including mixed dementia). The prevalence of all dementia and AD increased steeply with advancing age and was consistently higher in women, but it was not obviously higher for VaD in women. Alzheimer's disease was the commonest type of dementia. Our prevalence figures for dementia and AD are similar to those previously reported for China.

Liu HC, Fuh JL, Wang SJ, Liu CY, Larson EB, Lin KN, Wang HC, Chou P, Wu ZA, Lin CH, Wang PN, Teng EL. Prevalence and subtypes of dementia in a rural Chinese population. Alzheimer Dis Assoc Disord. 1998 Sep;12(3):127-34.

We conducted a single-stage community-based study of dementia on all registered residents > or =65 years in age in a rural Chinese community. Neurologists conducted semistructured interviews and examined all participants; they also interviewed family members in cases where dementia was suspected. The diagnosis was made by consensus according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 3rd ed, revised (DSM-III-R). Among the 2,055 contacted individuals, 1,736 (84.5%) participated in the study and 44 ( 13 men and 31 women) were diagnosed as having dementia, including 35 (80%) with probable Alzheimer disease (AD) and 3 (7%) with vascular dementia (VsD). The rates of dementia were 0.5% for ages 65-74 years, 2.9% for ages 75-84 years, and 12.0% for ages 85-101 years. The overall rate was 2.5% for age > or =65 years. After controlling for age, neither a lack of formal education nor being a woman was a risk factor for dementia. At 2-year follow-up, 30 of the 44 demented participants had died, yielding a 2-year survival rate of 32%. The present results corroborated our previous findings of lower prevalence rates of dementia among the Chinese than among Western populations, and both genetic and sociocultural factors may have contributed to the low rates. The lack of neuroradiological imaging studies in the present study may have contributed to the finding of an unusually low rate of VsD.

Liu HC, Chou P, Lin KN, Wang SJ, Fuh JL, Lin HC, Liu CY, Wu GS, Larson EB, White LR, et al. Assessing cognitive abilities and dementia in a predominantly illiterate population of older individuals in Kinmen. Psychol Med. 1994 Aug;24(3):763-70.

A community survey of dementia was conducted on a Chinese islet. A total of 221 men and 234 women in the age range of 50-92 were assessed. The Cognitive Abilities Screening Instrument (CASI), a 100-point cognitive test designed for cross-cultural studies and adapted in Chinese for individuals with little or no formal education, was administered twice by trained field workers with a retest interval of 3 to 4 weeks. In addition, all participants were assessed by physicians who did not know the CASI scores. The physicians' assessment included a complete neurological examination, plus semi-structured tests and interviews covering cognitive abilities, daily activities, depression, cerebrovascular disease, and Parkinson's disease. Dementia was diagnosed by consensus among the physicians according to the DSM-III-R criteria. Among the 455 participants, 16 cases of dementia were identified, including 13 with probable Alzheimer's disease and 1 each with vascular dementia, Parkinson's disease, and alcoholism. The rates of dementia were 0, 3.9 and 11.5% for the age groups of 50-69, 70-79 and 80-92; and 4.4, 2.0 and 0% for the education groups of 0-1, 2-6 and 7-15 years of schooling. No sex difference was found after controlling for education. The Chinese version of the CASI had an intraclass retest reliability of 0.90. Using a cut-off score of < or = 50 for dementia, the sensitivity was 0.88 and the specificity was 0.94. The preliminary study suggests that the CASI can be used in Chinese populations with generally low education levels and that Alzheimer's disease was the most common type of dementia in this population.

Shen YC, Li G, Li YT, Chen CH, Li SR, Zhao YW, Zhang WX. Epidemiology of age-related dementia in China. Chin Med J (Engl). 1994 Jan;107(1):60-4.

The results of these epidemiological studies suggest that the morbidity of age related moderate and severe dementia among the population of 65+ was 1.82%, when adjusted by 1984 US population ratio, it became 3.2%, as reported by US and European authors. Yet MID appears more common than PDD, which was more close to the data from Japan. The average annual incidence of moderate and severe dementia for persons aged 60+ was 0.3% (95% CI: 0.08%-0.52%). The incidence for those aged 70-79 (0.41%) was similar to that reported by US authors (Sluss), 0.58% among 70-74 years old, but lower than that observed by European authors (Hagnell, Magnusso) varied from 1.2% to 5.2% in the same age group. These great differences are likely to be partly due to differences in the age structure of samples, instruments for testing dementia, and diagnostic criteria. The course and outcome of dementia after 3-year follow-up indicated that the average survival time was 8 years, and the risk for death of dementia was 3 times higher than that of the whole cohort; the results were similar to those reported by westerners. The major risk factors for AD as identified in this study showed that family history both in first degree relatives of AD and psychosis were significantly associated with AD. The finding was consistent with the genetic hypothesis in western countries. In 7 risk factors that have been studied in US and European countries, 6 showed that the family history of dementia was significantly associated with AD.

Zhang MY, Katzman R, Salmon D, Jin H, Cai GJ, Wang ZY, Qu GY, Grant I, Yu E, Levy P, et al. The prevalence of dementia and Alzheimer's disease in Shanghai, China: impact of age, gender, and education. Ann Neurol. 1990 Apr;27(4):428-37.

We report the prevalence rates for dementia and Alzheimer's disease (AD) obtained from a probability sample survey of 5,055 noninstitutionalized older persons in Shanghai, China. A two-stage procedure was used for case finding and case identification. A Chinese version of the Mini-Mental State Examination was used to determine cases of possible dementia. Three different cutoff points on this mental status test were used depending on the respondent's level of education. Clinical evaluations, based on functional assessments and psychiatric interview, medical and neurological examinations, three standardized mental status tests, and a selected group of psychometric tests, were made in the second stage of the study to ascertain the clinical diagnosis of dementia and AD utilizing the Diagnostic and Statistical Manual for Mental Disorders, edition 3 and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria, respectively. The prevalence rate of dementia in persons 65 years and older was 4.6%. Clinically diagnosed AD accounted for 65% of the subjects with dementia. These findings indicate that the prevalence of dementia in Shanghai is very much higher than figures published earlier for China and Japan, and at the lower part of the range of values reported for community residents in the United States and other Western countries, but less than half of that reported in the recently published survey of the elderly in East Boston. Increasing age, gender (female), and low education are each highly significant and independent risk factors for dementia. One hypothesis to explain the increased prevalence in elderly women who had received no formal education invokes the possibility of an effect of early deprivation, perhaps lowering brain "reserve," allowing the symptoms of dementia to appear at an earlier date during disease progression.

Wang G, Cheng Q, Zhang S, Bai L, Zeng J, Cui PJ, Zhang T, Sun ZK, Ren RJ, Deng YL, Xu W, Wang Y, Chen SD. Economic impact of dementia in developing countries: an evaluation of Alzheimer-type dementia in Shanghai, China. J Alzheimers Dis. 2008 Sep;15(1):109-15.

The main objective of this study was to assess the economic cost of Alzheimer's disease (AD) in Shanghai, China, as a pilot study for future evaluations. Sixty-seven patients with AD were interviewed, and the information of the AD-related cost and resources used was collected from October 2005 to September 2006. By retrospective analysis, annual costs were calculated and expressed in Chinese renminbi (RMB). Direct cost per patient per year averaged approximately 8,432 RMB (1,058 USD), indirect cost per patient per year was 10,568 RMB (1,326 USD), and annual costs were 19,001 RMB (2,384 USD) per patient per year in this investigation. Total cost was significantly associated with the degree of severity including cognitive function (MMSE) and activity of daily living (ADL). With the increase in the number of persons at risk for developing AD, the economic burden of AD patients in China is significantly heavy.