The Lancet：中国和其他发展中国家的痴呆症水平被低估

由英国伦敦大学国王学院（King’s College London）的科学家领导的与中国北京大学的同事合作开展的一项大规模国际研究提示，中国和其他发展中国家的痴呆症患者的数量比此前认为的要多得多。即将发表在《柳叶刀》The Lancet杂志上的这项研究是首个发现中国、墨西哥和秘鲁等国家的痴呆症发病率可能与西方发达国家一样多的研究。此外，这是首个研究以证明在较不发达的国家和在发达国家一样，教育都能为防范痴呆症提供实质性的保护。

根据世界卫生组织（WHO）的数字，全世界有3560万人患痴呆症，这个数字预计每20年就会翻一番。表现为认知功能恶化的痴呆症是老年人残疾和依赖性的主要原因——这不仅对于病人，而且对于病人的家属和护理提供者来说也是无法抵抗的。常常因缺乏对痴呆症的认识和理解，而导致了污名化以及对诊断和治疗的阻碍。

这组科学家使用一种对较轻的病例敏感的新的跨文化方法，从而评价中国人口以及古巴、多米尼加共和国、委内瑞拉、秘鲁和墨西哥人口中的痴呆症水平。与此前的许多仅限于单个地点的研究不同，他们的研究涉及了农村和城市地区的将近1.28万名年龄在65岁和65岁以上的人。他们比较了痴呆症的发病率，从而确定诸如教育和文化水平等因素是否能预防这种综合征的发展。

他们发现，痴呆症的发病率是使用此前的标准方法计算出的发病率的1.5倍到2.5倍。在对年龄进行标准化之后，研究人员发现痴呆症发病率一致性地类似于或者高于此前欧洲研究观察到的痴呆症发病率。

“我们在中国发现的痴呆症发病率之高提醒我们，我们正面临一场全球性的流行，而且需要把注意力更多地放在预防上，”领导了这项研究的伦敦大学国王学院的Martin Prince教授说。“我们的发现提示，在北京城市和农村环境中的发病率类似于在欧洲高收入国家发现的发病率。”

“我们的研究为认知储备假说——更好的大脑发育可以缓解晚年的神经退化效应——提供了支持性的证据。这些发现提示，早期生活的影响、教育以及学习读写可能对于减少晚年的痴呆症的风险具有特别的重要性。我们需要更多地理解认知储备、如何衡量它，以及它在各种文化中是如何被激发的。”

与那些没有痴呆症的人相比，在该研究开始的时候有痴呆症的人死亡的风险几乎是前者的3倍。这些发现还表明了痴呆症的发病率与年龄增加、性别为女性以及教育程度低独立地相关，但是与职业成就不相关。

这组科研人员此前发现了北京城区和农村地区在护理安排上的差异。北京城区一半以上的患痴呆症的老年人是由雇佣的住家看护人员照顾的，而农村地区的患痴呆症的人几乎都是由家庭成员照顾的，这些人常常是未受过培训的而且可能不得不放弃他们的工作。（生物谷Bioon.com）

doi:10.1016/S0140-6736(12)60399-7
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Dementia incidence and mortality in middle-income countries, and associations with indicators of cognitive reserve: a 10/66 Dementia Research Group population-based cohort study

Prof Martin Prince MD a , Daisy Acosta MD b, Cleusa P Ferri PhD a, Mariella Guerra PhD c, Prof Yueqin Huang PhD d, Prof Juan J Llibre Rodriguez PhD e, Aquiles Salas MD f g, Ana Luisa Sosa PhD h, Joseph D Williams MD i, Prof Michael E Dewey PhD a, Isaac10:25 2012-5-23 Acosta MSc h, Amuthavalli T Jotheeswaran MSc j, Zhaorui Liu MPH d

Background Results of the few cohort studies from countries with low incomes or middle incomes suggest a lower incidence of dementia than in high-income countries. We assessed incidence of dementia according to criteria from the 10/66 Dementia Research Group and Diagnostic and Statistical Manual of Mental Disorders (DSM) IV, the effect of dementia at baseline on mortality, and the independent effects of age, sex, socioeconomic position, and indicators of cognitive reserve. Methods We did a population-based cohort study of all people aged 65 years and older living in urban sites in Cuba, the Dominican Republic, and Venezuela, and rural and urban sites in Peru, Mexico, and China, with ascertainment of incident 10/66 and DSM-IV dementia 3—5 years after cohort inception. We used questionnaires to obtain information about age in years, sex, educational level, literacy, occupational attainment, and number of household assets. We obtained information about mortality from all sites. For participants who had died, we interviewed a friend or relative to ascertain the likelihood that they had dementia before death. Findings 12 887 participants were interviewed at baseline. 11 718 were free of dementia, of whom 8137 (69%) were reinterviewed, contributing 34 718 person-years of follow-up. Incidence for 10/66 dementia varied between 18·2 and 30·4 per 1000 person-years, and were 1·4—2·7 times higher than were those for DSM-IV dementia (9·9—15·7 per 1000 person-years). Mortality hazards were 1·56—5·69 times higher in individuals with dementia at baseline than in those who were dementia-free. Informant reports suggested a high incidence of dementia before death; overall incidence might be 4—19% higher if these data were included. 10/66 dementia incidence was independently associated with increased age (HR 1·67; 95% CI 1·56—1·79), female sex (0·72; 0·61—0·84), and low education (0·89; 0·81—0·97), but not with occupational attainment (1·04; 0·95—1·13). Interpretation Our results provide supportive evidence for the cognitive reserve hypothesis, showing that in middle-income countries as in high-income countries, education, literacy, verbal fluency, and motor sequencing confer substantial protection against the onset of dementia. Funding Wellcome Trust Health Consequences of Population Change Programme, WHO, US Alzheimer's Association, FONACIT/ CDCH/ UCV