北京大学国家发展研究院教授、北京大学健康老龄与发展研究中心主任曾毅与4位合作者联署的题为“Survival, disability in activities of daily living, physical and cognitive functioning among the oldest-old in China: a cohort study”的论文日前在国际医学健康科学最顶级学术期刊《柳叶刀》（The Lancet）发表（该刊2014/2015年影响因子为45.2）。
在人口老化和老龄健康领域，目前国际上一种理论认为，随着社会经济发展，老年人口在延长寿命的同时残障期也会缩短，被称为“胜利的胜利”（success of success）；然而，另一种理论认为，老年人寿命延长同时使虚弱者存活，导致老年人群中残障比例增加，被称为“胜利的失败”（failure of success）。目前国际上对这两种理论的实证研究和争议较多，但尚无定论，尤其国外关于高龄老人的研究样本较小，难以得出稳健结论。
针对这一个重要议题，曾毅及其合作者基于北京大学国家发展研究院健康老龄与发展研究中心自1998年启动、已持续进行17年的“中国老龄健康影响因素跟踪调查研究”近两万名80岁及以上高龄老人数据进行分析发现，2008年高龄老人死亡率和日常生活自理能力 （吃饭、穿衣、洗澡、室内活动、自己去厕所和随后自我清洗）残障比例比1998年显著下降。但是，2008年高龄老人躯体活动能力测试（从坐在椅子上自己独立站起来、捡起地上的书、自转一圈）以及认知功能的残障比例比10年前显著增长。如何解释这些似乎相互矛盾的发现呢？曾毅等认为，十几年来，老百姓生活水平大大提高和医疗进步，使高龄老人健康状况某些方面有改善，加上帮助他们的日常生活辅助设施条件（如洗澡、厕所设施，冰箱、洗衣机普及等）有所改善，导致日常生活能力残障比例下降。但是，医疗条件与生活水平改善同时使健康较差的高龄老人存活率提高，不少按以前医疗和生活条件可能已死亡的高龄老人被“救”而活下来了，导致平均躯体活动能力和认知功能残障率增高，这将给社会长期照料和亿万家庭生活质量带来严峻挑战。基于实证分析以及相关的理论探讨，曾毅等在《柳叶刀》发表的论文认为，国际相关文献中广泛使用的“胜利的失败”概念用词太过悲观夸张，建议将它修正为更加客观准确的概念用词“胜利的成本（costs of success）”及其相对应的 “胜利的效益（benefit of success）”，并进行了相应的成本效益分析。其核心思想是：人类寿命提高（胜利）带来效益的同时，也有一定的成本，而成本不是以往不少国际文献所称的“失败（failure）”，因此没有必要为此而恐慌，但需要积极奋发应对，研究制订和实施一系列行之有效的政策措施，全社会共同努力，实现人口和经济社会健康老龄化。
《柳叶刀》杂志集团将曾毅等的这一论文作为重要科学发现专门举行了面对全球的网上新闻发布，宣布“这是世界上规模最大的高龄老人研究，其发现对中国和其他所有面临人口老化挑战的国家都有重要意义”。《柳叶刀》还邀请加拿大两位著名老龄健康学者专门对这一重要发现撰写了积极肯定的评论。
延伸阅读：
《柳叶刀》集团从The Lancet主刊及医学健康科学12个专业领域子刊共13个学术期刊每周发表的大约120篇论文中挑选1-3篇他们认为最重要的科学发现举行面对全球的网上新闻发布。以下是《柳叶刀》杂志集团将曾毅等的论文作为重要科学发现专门举行的面对全球的网上新闻发布稿。
THE LANCET: Chinese oldest-old population is growing but individuals have poorer physical and cognitive function
The number of people living beyond 80 years old – from octogenarians to centenarians – in China is growing but they have poorer physical and cognitive function compared with their counterparts from 10 years ago, according to the largest study of its kind, published in The Lancet.
Population ageing is one of the major challenges facing most countries in the world. With the oldest-old population (those aged 80 years old or over) set to grow much faster than other age groups, this poses challenges for health systems, social care and families as this group often need daily assistance and medical care.
Previous studies have found opposing results when researching the health of this group, with some research suggesting people are living longer and in better health, while other studies suggest people are living in worse health as they age.
These differences may be a result of advances in medical technology, lifestyle improvements and increased socioeconomic status postponing disability and chronic diseases for the oldest-old group, or of lower mortality meaning more elderly people survive with chronic health problems.
To study these effects, the researchers compared 19528 people [1] aged 80-105 in China who were born 10 years apart. In the Chinese Longitudinal Healthy Longevity Study surveys taken in 1998 and 2008, the researchers estimated mortality rates and analysed data of participants’ physical ability (from three tests of whether they could stand up from a chair, pick up a book from the floor and turn around 360 degrees), cognitive function and self-reported problems in daily activities (eating, dressing,transferring, using the toilet, bathing and continence) .
They found that mortality was lower for the oldest-old who were born a decade later – meaning a greater proportion of people in each age group in the 2008 survey were surviving. For octogenarians, mortality decreased from 10.3% in 1998 to 9.6% in 2008; for nonagenarians, mortality decreased from 24.1% to 23.4%; and from 40.7% to 38.0% for centenarians.
However, those surveyed in 2008 had worse physical function than their counterparts from 10 years earlier, and this was the same for all age groups. The same was true of cognitive function, where the average cognitive function score for octogenarians, nonagenarians and centenarians decreased between 1998 and 2008.
Despite this, the group born later reported fewer difficulties performing daily activities than those born 10 years earlier.
The researchers say that these opposing findings illustrate that two theories of ageing are at play – the benefits and costs of success of living longer.
The ‘benefits of success’ theory suggests that people are living longer with lower levels of disability in daily living as a result of better medications, leading healthy lifestyles, having fewer disabilities caused by chronic diseases, and because improvements in socioeconomic status and living standards have helped to facilitate daily living and delay deterioration as they age. Whereas the ‘costs of success’ theory suggests that living longer might mean frail individuals survive life-threatening illnesses but live with health problems as a result – meaning the oldest-old population faces lower levels of physical and cognitive function.
“The findings of our study provide a clear warning message to societies with ageing populations – although lifespans are increasing, other elements of health are both improving and deteriorating leading to a variety of health and social needs in the oldest-old population.” said lead author Professor Yi Zeng, National School of Development at Peking University (China) and Medical School of Duke University (USA). “This combination poses an enormous challenge for health systems, social care and families around the world. In order to live well for longer, it is important to develop more services to meet the various needs of growing elderly populations. For those with disabilities this may include long-term and acute daily care as well as mobility aids. While for those living well, working opportunities, social and leisure activities, continued learning and psychological counselling could support them to continue living well for longer.” [2]
The researchers note that those assessed in 2008 may have reported fewer difficulties in their day-to-day lives as a result of having better amenities and tools that support them in their daily activities. However, the researchers say that more in-depth studies will be needed to confirm how and why levels of self-reported disability in daily living decreased while observed levels of disability in physical and cognitive functions increased in 2008.
They also propose that further research could include prevalence of chronic diseases and other older age groups (those aged 65-79 years) to help fully understand the process of ageing healthily and could provide more evidence for the types of interventions needed to support this age group.
Writing in a linked Comment, Professor Kenneth Rockwood, Dalhousie University, Canada, said: “The population that was old in China at the end of the 20th century had been through enormous social changes, including in government and social organisation, income levels, and food security. Later changes – such as migration to rapidly growing urban areas, the one child policy, and variable access to health care – each would have affected the health of China’s oldest-old. For example, just as education and socioeconomic factors might mitigate the disabling nature of poor physical performance, they might also account for the increased cognitive impairment in the later-born cohorts, who have had less educational opportunity. The health costs and benefits of improved longevity are not just a matter of science: what people desire matters too. For the part that is science, however, we need measures that are precise enough to allow light to be shed on the puzzle of unexplained heterogeneity in health among people of the same age.”
NOTES TO EDITORS
The study was funded by the National Natural Science Foundation of China, US National Institute of Aging and the United Nations Funds for Population Activities. It was conducted by scientists from Peking University, Duke University School of Medicine, National University of Singapore, University College London, Zhejiang University, University of Southern Denmark and the Max Planck Institute for Demographic Research.
For more information about the Chinese Longitudinal Healthy Longevity Study, please see:https://sites.duke.edu/centerforaging/programs/chinese-longitudinal-healthy-longevity-survey-clhls/
[1] Within the study, there were 7288 people aged 80-89 years (3235 people in 1998 and 4053 people in 2008), 7234 aged 90-99 years (2896 in 1998, 4338 in 2008), and 5006 aged 100-105 years (2197 in 1998, 2809 in 2008).
[2] Quote direct from author and cannot be found in the text of the Article.
For interviews with the second author Qiushi Feng, Singapore, please contact: E)fengqiushi@nus.edu.sgT) +65 6516 4420; For interviews about the Chinese Longitudinal Healthy Longevity Study, please contact Xiaoyan Lei, standing associate director of the Center for Healthy Aging and Development Study at National School of Development of Peking University, China: E)xylei@nsd.pku.edu.cnT) +86 10 62758946; For email communication with lead author, Yi Zeng, Peking University and Duke University, please contact: E)zengyi@nsd.pku.edu.cn
For interviews with Comment author, Professor Kenneth Rockwood, Dalhousie University, Canada, please contact E)rockwoodtravel@gmail.comT) +1 902 488 8631
For embargoed access to the Article & Comment, please see:http://press.thelancet.com/oldestold.pdf
For embargoed access to the Appendices, please see:http://press.thelancet.com/oldestoldAPPX.pdf
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