Towards a core outcome set (COS) for intrinsic capacity (IC) intervention studies in adults in midlife and beyond: a scoping review to identify frequently used outcomes and measurement tools.

"Declarations Conflict of interestDS-R, OB, Y-IR, and CB serve as Senior Advisors to the World Health Organization (WHO) Collaborating Center for Epidemiology of Musculoskeletal Health and Aging, Division of Public Health, Epidemiology, and Health Economics, University of Liège, Liège, Belgium. Y-IR serves as a member of the Board of Directors of the Clinical Consortium on Healthy Ageing (CCHA) of the WHO, Geneva, Switzerland. All authors declare they do not have any personal or financial relationships with other organizations or people that could inappropriately influence their work. Ethical approvalThis is a scoping review, for this study type, Ethics Committee approval is not required. Informed consentFor this type of study, formal consent is not required. Conflict of interest DS-R, OB, Y-IR, and CB serve as Senior Advisors to the World Health Organization (WHO) Collaborating Center for Epidemiology of Musculoskeletal Health and Aging, Division of Public Health, Epidemiology, and Health Economics, University of Liège, Liège, Belgium. Y-IR serves as a member of the Board of Directors of the Clinical Consortium on Healthy Ageing (CCHA) of the WHO, Geneva, Switzerland. All authors declare they do not have any personal or financial relationships with other organizations or people that could inappropriately influence their work."

"Funding No funding has been received to conduct this review."

"This ScR followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) (Completed checklist is available in Supplementary material, Table 1S) []. The COS-STAD for the design of a COS study was followed as far as possible [, , ]. The protocol was registered in the International prospective register of systematic reviews (PROSPERO, CRD42023437223), Open Science Framework, and the Core Outcome Measures in Effectiveness Trials (COMET) database on June 2023."