Series Neurological diseases in China 3 Dementia in China: epidemiology, clinical management, and research advances Longfei Jia, Meina Quan, Yue Fu, Tan Zhao, Yan Li, Cuibai Wei, Yi Tang, Qi Qin, Fen Wang, Yuchen Qiao, Shengliang Shi, Yan-Jiang Wang, Yifeng Du, Jiewen Zhang, Junjian Zhang, Benyan Luo, Qiumin Qu, Chunkui Zhou, Serge Gauthier, Jianping Jia, for the Group for the Project of Dementia Situation in China* China has the largest population of patients with dementia in the world, imposing a heavy burden on the public and Lancet Neurol 2019 health care systems. More than 100 epidemiological studies on dementia have been done in China, but the estimates Published Online of the prevalence and incidence remain inconsistent because of the use of different sampling methods. Despite September 4, 2019 improved access to health services, inadequate diagnosis and management for dementia is still common, particularly http://dx.doi.org/10.1016/ S1474-4422(19)30290-X in rural areas. The Chinese Government issued a new policy to increase care facilities for citizens older than 65 years, This is the third in a Series of but most patients with dementia still receive care at home. Western medicines for dementia symptoms are widely four papers about neurological used in China, but many patients choose Chinese medicines even though they have little evidence supporting efficacy. diseases in China The number of clinical trials of Chinese and western medicines has substantially increased as a result of progress in *Study group listed at the end of research on new antidementia drugs but international multicentre studies are few in number. Efforts are needed to the paper establish a national system of dementia care enhance training in dementia for health professionals, and develop Innovation Center for global collaborations to prevent and cure this disease. Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Introduction In this Review, we highlight the epidemiology, eco­ Medical University, Beijing, Dementia is a leading cause of disability in people older nomic burden, health­service system, and clinical trials of China (Prof J Jia MD, L Jia MD, than 65 years worldwide, including China.1–3 The number Alzheimer’s disease and other dementias in China. We M Quan MD, Y Fu MD, of patients with dementia in China accounts for approxi­ also discuss whether Chinese medicines have potential T Zhao MD, Y Li MS, C Wei MD, Y Tang MD, Q Qin MD, mately 25% of the entire population with dementia efficacy on dementia and, on the basis of progress and F Wang MD, Y Qiao BS); Beijing worldwide,4 creating a huge challenge for policy makers, challenges to date, we propose future priorities regarding Key Laboratory of Geriatric health­care professionals, and family members. In res­ the care of patients with dementia for policy makers, Cognitive Disorders, Beijing, China (Prof J Jia); Clinical Center ponse, over the past 10 years, the Chinese Government clinicians, and researchers in China and worldwide. This for Neurodegenerative Disease and dementia organisations have imple mented a series of Review will not include those with other types of dem­ and Memory Impairment, plans, culminating in the 13th Five­Year Plan to manage entia, such as frontotemporal demen tia, dementia with Capital Medical University, this disease, previous iterations of which have improved Lewy bodies, and Parkinson’s disease dementia, because Beijing, China (Prof J Jia); Center of Alzheimer’s Disease, Beijing the access of patients with dementia to health­care the data were generally not available. Institute for Brain Disorders, services. In part icular, the national pro gramme for train­ Beijing, China (Prof J Jia); ing dementia doctors, the implementation of new Epidemiology Department of Neurology, dementia guidelines,5,6 and the increased availability of Prevalence The Second Affiliated Hospital 7 of Guangxi Medical University, neuroimaging technologies, including MRI and PET, Over the past decade, many studies have focused on the Nanning, China (Prof S Shi MD); have enabled earlier and more accurate diagnosis of prevalence of dementia in China (appendix pp 3–8). A Department of Neurology and patients who might previously have been misdiagnosed or survey done in 1990 suggested that the prevalence of Center for Clinical overlooked. However, the success of these advances differs dementia was 4·60% and Alzheimer’s disease was Neuroscience, Daping Hospital, 15 Third Military Medical between urban and rural areas in China. In rural areas, 2·99% in individuals aged 65 years and older. In 2005, the University, Chongqing, China patients usually have difficulty access ing health services prevalence of Alzheimer’s disease was reported to be (Prof Y J Wang MD); Department (such as dementia specialist, memory clinics, and imag­ 3·5% following a large­sample, population­based survey in of Neurology, Shandong 8 16 Provincial Hospital Affiliated to ing facilities) com pared with patients in urban areas. four regions (with rural and urban areas). Thereafter, Shandong University, Jinan, Additionally, advances in diag nostic technology and many studies were done, but the results showed a broad China (Prof Y Du MD); methods have resulted in changes to diagnostic criteria,9–11 range for dementia prevalence, from 5·0% to 7·7% for Department of Neurology, which might affect the accuracy of epidemiological studies individuals aged 60 years and older and from 2·0% to Henan Provincial People’s and the results of clinical trials undertaken before 13·0% for individuals aged 65 years and older.17–24 However, Hospital, Zhengzhou University People’s Hospital, changes to diagnostic criteria. Since the 1990s, more than many of these surveys were done in single regions with Zhengzhou, China 100 epidemiological studies have been done in China small sample sizes and might not reflect the actual (Prof Ji Zhang MD); Department that have greatly contributed to the knowledge regard­ epidemiology. Two large­sample, multiregion studies have of Neurology, Zhongnan ing dementia prevalence and inci dence.12–14 However, been done, the first in 201425 and the second in 2019.26 Hospital, Wuhan University, Wuhan, China other aspects of the disease remain unclear and might The studies showed that the prevalence of dementia was (Prof Ju Zhang MD); limit the understanding of the disease from a national 5·14% (95% CI 4·71–5·57) in 2014,25 and 5·60% (3·50–7·60) Department of Neurology, perspective. in 201926 for individuals aged 65 years or older. The First Affiliated Hospital, www.thelancet.com/neurology Published online September 4, 2019 http://dx.doi.org/10.1016/S1474-4422(19)30290-X 1 Series Zhejiang University, A meta­analysis of 96 observational studies, published in (7·64%) in patients aged 60 years and older.30 The Hangzhou, China 2018, reported that the overall prevalence of dementia differences in global prevalence might be explained by (Prof B Luo MD); Department of in Chinese people aged 60 years and older was different demen tia survival time, environmental risk Neurology, The First Affiliated 13 Hospital of Xi’an Jiaotong 5·30% (4·30–6·30). The prevalence of dementia and factors and genetic factors, and mortality before the onset University, Xi’an, China Alzheimer’s disease was substantially higher in rural of dementia.31 Moreover, the heterogeneity in research (Prof Q Qu MD); Department of populations than in urban populations (6·05% vs 4·40% methods, including the use of different diagnosticcriteria, Neurology, The First Teaching 32,33 Hospital of Jilin University, for dementia and 4·25% vs 2·44% for Alzheimer’s disease), can affect results regarding dementia prevalence. Changchun, China probably due to the lower edu cational level in rural Thus, further investigation with a consistent method of (Prof C Zhou MD); and regions.25 Age and sex also affect dementia prevalence.12,25,27 diagnosing dementia is needed for confirmation of disease Departments of Neurology and A systematic review of 75 observational studies, published prevalence. Neurosurgery, and Department of Psychiatry, McGill Centre for in 2013, showed that the prevalence of dementia had Few multicentre and large­scale studies have been done Studies in Aging, McGill doubled at 5­year intervals (from the age of 55 to 99 years) on the prevalence of mild cognitive impairment in China University, Montreal, QC, and was higher in women than in men (the ratio of women over the past 10 years (appendix pp 3–8). From 2009 to Canada (Prof S Gauthier MD) to men was 1·65).12 The sex difference in the Alzheimer’s 2015, six studies that used different diagnostic criteria Correspondence to: disease prevalence was even higher (the ratio of women showed mild cognitive impairment prevalence ranging Prof Jianping Jia, Innovation 12 20,34–38 Center for Neurological to men was 2·37), which might be due to hormonal from 9·70% to 23·30% in Chinese individuals. These 28,29 Disorders, Department of differences and brain development factors. The number studies were done in single regions and did not rep­ Neurology, Xuanwu Hospital, of patients with dementia also varies in different geo­ resent the prevalence of mild cognitive impairment on a Capital Medical University, graphical areas; the prevalence of dementia is 5·5% in national scale. Subsequently, a study in multiple regions, Beijing 100053, China [email protected] northern China, 5·2% in central China, 4·8% in southern which included both urban and rural areas, reported China, and 7·2% in western China,