Determinants and trajectories of healthy life expectancy and deficit accumulation in older adults in Germany - follow-up of the KORA-Age cohort study

如果预期寿命的延长和出生率的放缓增加了慢性病患者在人口中所占的比例，那么这将是一个组织和财政挑战。关于发病率的压缩或扩大的经验证据仍然是矛盾的。健康预期寿命(HLE)因国家而异，德国低于欧洲平均水平。在这里，性别、年龄阶层和出生队列的估计是模棱两可的。健康预期寿命的异质性可能是由于关键(战前、战后)生命周期的影响，也可能是由于生命周期中机能状态的逐渐恶化，即赤字累积。因此，我们建议在一个具有代表性的德国老年人口样本中研究HLE的决定因素，考虑出生队列和DA的早期生活经历。我们计划使用成熟的KORA(奥格斯堡地区合作卫生研究)平台进行新的数据收集，并使用我们现有的来自KORA-Age队列的数据。我们计划在KORA年龄队列中检查HLE和DA作为出生队列和性别的函数，并检查DA与死亡率的关系。自1984年以来，在德国奥格斯堡和周围的两个县进行了四项基于人口的横断面研究，即KORA调查S1至S4。KORA年龄队列包括2008年底KORA调查中年龄在65岁或以上的所有参与者，即1943年或之前出生的人。KORA-年龄的基线研究于2009年进行。拟议的队列研究将作为对KORA-年龄基线研究估计2500名参与者的7年重新评估。参与者将在2015/2016年间年龄在73岁至96岁之间(年龄较大的分组，第I层)。此外，KORA调查的年轻参与者在2008年底还不到65岁，因此没有资格参加KORA年龄基线，但到2015年底将达到65岁至72岁，将作为所有KORA S1-S4参与者(即1944年至1950年出生，年轻亚组，第二层)的按年龄和性别分层的样本。所有信息将通过邮寄健康跟踪、一份简短的健康问卷和电话访谈的方式获得。健康预期将被定义为在不同健康状态下度过的直到死亡的时间。作为DA的综合衡量标准，将按照明确的程序构建赤字累积指数(DAI)。DAI将包含体征和症状、疾病、功能障碍和活动限制。多变量对数线性、混合效应和COX回归模型将适用于数据。包括大范围的出生队列，并进行纵向随访，应该能够理清导致发病率压缩或延长的机制，将年龄、月经和队列效应分开。

Increasing life expectancy combined with slowing birth rates will be an organizational and financial challenge if this increases the share of persons in the population living longer periods of time with chronic disease. Empirical evidence regarding the compression or extension of morbidity is still ambivalent. Healthy life expectancy (HLE) varies largely across countries, with Germany being below the European average. Here, estimates are ambiguous across gender and age strata and birth cohorts. Heterogeneity in healthy life expectancy can be due to the influence of critical (pre-, peri-post-war) life periods or to the gradual deterioration of functional status over the life span, i.e. deficit accumulation (DA). We therefore propose to study determinants of HLE in a representative sample of the aged German population, taking early life experience as a consequence of birth cohort and DA into account. We plan to use the well-established KORA (Cooperative Health Research in the Region of Augsburg) platform for a new data collection, and to use our already existing data from the KORA-Age cohort. We plan to examine HLE and DA as a function of birth cohort and sex in the KORA Age cohort, and to examine the association of DA with mortality. Since 1984 four cross-sectional population based studies, the KORA surveys S1 to S4, were conducted in Augsburg, Germany, and two surrounding counties. The KORA-Age cohort includes all participants from those KORA surveys aged 65 years or older at the end of 2008, i.e. born in or before 1943. The baseline study of KORA-Age took place in 2009. The proposed cohort study will be carried out as a 7-year re-assessment of estimated 2500 participants of the KORA-Age baseline study. Participants will be aged 73 to 96 years in 2015/2016 (older subgroup, stratum I). Additionally, the younger participants from the KORA surveys who were not yet 65 at the end of 2008 and thus not eligible for KORA-Age baseline but will be 65 to 72 at the end of 2015 will be included as an age- and sex-stratified sample of all KORA S1-S4 participants (i.e. born from 1944 to 1950, younger subgroup, stratum II). All information will be obtained by means of a postal health follow-up with a short health questionnaire and a telephone interview. Health expectancy will be defined as the time spent in different health states until death. As summary measure for DA, a Deficit Accumulation Index (DAI) will be constructed according to a well-defined procedure. The DAI will contain signs and symptoms, diseases, functional impairments and activity restrictions. Multivariable log-linear, mixed-effects and Cox regression models will be fitted to the data. Including a wide span of birth cohorts with longitudinal follow-ups should make it possible to disentangle the mechanisms that lead to a compression or extension of morbidity, separating age, period, and cohort effects.