IIASA Young Scientists Summer Program: Health Transitions and Social Capital in Sub-Saharan Africa

作为国际应用系统分析研究所(应用系统分析所)青年暑期科学家方案(青年科学家方案)参与者的拟议工作将通过应用新的方法方法调查社会资本因素对老龄化进程的微观影响来扩展研究。YSSP与Warren Sanderson和Vegard Skirbekk合作研究的学术价值在于解决了这样一个事实，即现有的使用纵向数据计算多状态生命表(MSLT)的方法无法将随时间变化的协变量纳入分析。在撒哈拉以南非洲(SSA)的背景下，很难按时间不变因素将个人划分为有意义的子类别，尽管年龄、性别、教育和地区差异可能在老龄化过程中发挥重要作用，但时变因素，如艾滋病毒状况、成年子女的存在(及其艾滋病毒状况)、婚姻状况和农业利润可能对健康老龄化也很重要。MSLT模型允许对衰老过程固有的残疾和恢复的复杂过程进行建模，并生成各种残疾类别下的预期寿命。虽然没有得到充分发展或广泛应用，但Yang&Amp；Hall(2008)提出了一种潜在有用的方法，将时变因素纳入MSLT模型，使用联立方程方法进行有限因变量建模。在IIASA期间，学生将进一步开发和应用这种方法，将随时间变化的协变量纳入MSLT计算，并分析这些协变量如何减少/推迟残疾发生和提高存活率。YSSP的研究将直接有助于论文计划，以及解决大量需要进一步研究的更广泛的影响。在不久的将来，南部非洲地区的老龄化问题将变得越来越重要--在今后几十年中，45岁以上的成年人人口的增长速度将超过许多南部非洲国家中任何年轻的10岁年龄组，目前可获得的数据表明，南部非洲地区慢性致残性疾病的死亡率高于世界上几乎所有其他地区(WHO 2005)。在发展中国家的农村社区，功能性残疾是一个极其重要的话题，在那里，基于政府的社会服务可能缺乏或根本不存在。除了人口健康的基本知识外，人们对这些人口中的残疾、发病率和死亡率的过程知之甚少。目前，关于发展中国家老龄化的现有研究还不能全面概述从健康生活到残疾再到死亡的过渡途径。这项研究将集中在SSA的衰老过程和功能障碍的发展方面。特别是，重点将是这些过程可能会因个人层面的特点而有所不同，这方面以前很少有研究。拟议工作的主要目的是弥补我们在特别行政区健康、残疾和生命历程方面的知识空白，为学术界作出贡献，并确定捐赠者/政策制定者可以实现变革的需要领域。

The proposed work as an International Institute for Applied Systems Analysis (IIASA) Young Summer Scientist Program (YSSP) participant would extend the research by investigating the micro-level impact of social capital factors on the aging process by application of a novel methodological approach. The intellectual merit of the YSSP research collaboration with Warren Sanderson and Vegard Skirbekk is to address the fact that existing methodologies for multi-state life table (MSLT) calculation using longitudinal data are not able to incorporate time-varying covariates into analysis. In the context of sub-Saharan Africa (SSA), disaggregating individuals into meaningful sub-categories by time-invariant factors is difficult though age, sex, education, and regional differences may play a substantial role in the aging process, time-varying factors such as HIV status, presence of adult children (and their HIV status), marital status, and agricultural profits may also be important for healthy aging. MSLT models allow for the modeling of the complex processes of disablement and recovery inherent to the aging process, and generate expectancies of years lived in various categorizations of disability. Though not fully developed or widely used, Yang & Hall (2008) propose a potentially useful method of incorporating time-varying factors into a MSLT model using a simultaneous equations approach to limited dependent variable modeling. During the time at IIASA, the student would further develop and apply this method for incorporating time-varying covariates into MSLT calculation, and analyze how these covariates may reduce/delay disability onset and increase survivorship. The YSSP research will directly contribute to dissertation plans, as well as addressing a broader impact that is in substantial need of further research. Aging in SSA is an issue that will be of increasing importance in the near future--the population of adults aged 45+ will grow more rapidly in the next decades than that of any younger 10-year age group in many SSA countries, and currently available data suggest that mortality rates from chronic, disabling disease in SSA are higher than almost all other regions of the world (WHO 2005). Functional disability is an exceedingly important topic in rural communities of the developing world, where government-based social services may be lacking or nonexistent. Beyond the basics of population health, extremely little is known about processes of disability, morbidity, and mortality in these populations. Currently existing research on aging in the developing world has not been able to give a comprehensive overview of the transition pathways from healthy life to disability to death. The research will focus on how processes of aging and the development of functional disabilities play out in SSA. In particular, the focus would be on how these processes may differ by individual-level characteristics, something which has received very little previous research in this context. The primary aim of the proposed work is to remedy this blank area of our knowledge of health, disability, and the life course in SSA, both to contribute to the scholarly community and identify areas of need where donors/policymakers could effect change.