Supplementary Material for: Study Protocol of the 10-year longitudinal Amersfoort Cohort Study on Functional decline, Healthy aging, and Frailty (AMCOHF) in a community-dwelling older population

Introduction: Frailty, characterized by a reduction in intrinsic capacity across multiple physiological systems, is a key concern in healthy aging. Insight in the trajectory of an individual's functional ability and intrinsic reserve capacity in a relatively younger population of older adults is lacking. This study aims to investigate the early stages of frailty by tracking trajectories of physical indicators of intrinsic capacity before frailty becomes clinically evident.
Methods: The AMersfoort COhort study on functional decline, Healthy aging and Frailty (AMCOHF) is a unique 10-year prospective cohort study evaluating the predictive value of longitudinal trajectories of physical parameters for frailty onset or robustness maintenance. An a-select community-dwelling robust population of Amersfoort (55-75 years) in the Netherlands will undergo baseline assessments for inclusion criteria and will be followed longitudinally every 2.5 years. Frailty status is assessed using the Fried phenotype, Rockwood frailty index, and Groningen frailty indicator. Testing procedures and questionnaire completion include physical performance tests in the domains: 1) musculoskeletal system, 2) articular system, 3) cardiorespiratory system, 4) sensory system, 5) immune system, and 6) uro-gynaecological system. Study outcomes focus on intrinsic capacity, functional ability, explanatory data, and frailty. Statistical analyses evaluating the predictive capacity include logistic regression, confirmatory factor or latent class analysis, and structural equation modeling. Non-probability convenience sampling recruits 2078 robust participants, estimating a 1-year frailty incidence of 1.5%-6.0%. Ethical approval was obtained, and the trial is prospectively registered on Open Science Framework (DOI: 10.17605/OSF.IO/RMBQV).
Conclusion: The AMCOHF study will contribute to knowledge about markers to predict an accelerated decline in intrinsic capacity in an early stage. This knowledge is important to deploy prevention strategies at an earlier stage in life then those currently undertaken, ultimately reducing healthcare costs and contributing to a healthy aging population.

引言：衰弱症（frailty）是以多生理系统内在能力减退为特征的健康老龄化核心关切问题。目前针对55至75岁这一相对年轻的老年群体，其个体功能轨迹与内在储备能力的相关认知仍存在缺口。本研究旨在通过追踪衰弱症临床显现前的内在能力物理指标变化轨迹，探究衰弱症的早期阶段。
方法：阿默斯福特功能衰退、健康老龄化与衰弱症队列研究（AMCOHF）是一项独特的10年前瞻性队列研究，旨在评估物理参数纵向轨迹对衰弱症发病或健康状态维持的预测价值。荷兰阿默斯福特市经初步筛选的社区居住健康群体（55-75岁）将接受基线评估以确认入组标准，并每2.5年进行一次纵向随访。衰弱状态的评估采用弗里德表型（Fried phenotype）、罗克伍德衰弱指数（Rockwood frailty index）以及格罗宁根衰弱指标（Groningen frailty indicator）。测试流程与问卷填写涵盖六大系统的体能测试：1）肌肉骨骼系统；2）关节系统；3）心肺系统；4）感觉系统；5）免疫系统；6）泌尿生殖系统。本研究的结局指标聚焦于内在能力、功能能力、解释性数据以及衰弱症。用于评估预测能力的统计分析方法包括逻辑回归、验证性因子分析、潜类别分析以及结构方程模型。本研究采用非概率便利抽样法，共招募2078名健康参与者，预估1年内衰弱症发病率为1.5%至6.0%。本研究已获得伦理批准，并在开放科学框架（Open Science Framework，OSF）上进行了前瞻性注册（DOI: 10.17605/OSF.IO/RMBQV）。
结论：AMCOHF研究将为识别可预测早期内在能力加速衰退的标志物提供理论依据。该研究成果有助于在比当前更早的人生阶段部署预防策略，最终降低医疗保健成本，助力实现健康老龄化的群体目标。