A1 Journal article (refereed)
Development and validation of an intrinsic capacity composite score in the Longitudinal Aging Study Amsterdam : a formative approach (2023)

Koivunen, K., Hoogendijk, E. O., Schaap, L. A., Huisman, M., Heymans, M. W., & van Schoor, N. M. (2023). Development and validation of an intrinsic capacity composite score in the Longitudinal Aging Study Amsterdam : a formative approach. Aging Clinical and Experimental Research, 35(4), 815-825. https://doi.org/10.1007/s40520-023-02366-2

JYU authors or editors

Koivunen, Kaisa

Publication details

All authors or editors: Koivunen, Kaisa; Hoogendijk, Emiel O.; Schaap, Laura A.; Huisman, Martijn; Heymans, Martijn W.; van Schoor, Natasja M.

Journal or series: Aging Clinical and Experimental Research

ISSN: 1594-0667

eISSN: 1720-8319

Publication year: 2023

Publication date: 23/02/2023

Volume: 35

Issue number: 4

Pages range: 815-825

Publisher: Springer Science and Business Media LLC

Publication country: Italy

Publication language: English

DOI: https://doi.org/10.1007/s40520-023-02366-2

Research data link: https://www.lasa-vu.nl/

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/85719

Additional information: The datasets generated during the current study are not publicly available due to confidentiality, but the data underlying the results presented in this study are available from the Longitudinal Aging Study Amsterdam (LASA) and may be requested for research purposes. More information on data requests can be found on the LASA website: www.lasa-vu.nl.

Abstract

Background
Intrinsic capacity (IC) defined by the WHO refers to the composite of five domains of capacities. So far, developing and validating a standardized overall score of the concept have been challenging partly because its conceptual framework has been unclear. We consider that a person’s IC is determined by its domain-specific indicators suggesting a formative measurement model.

Aims
To develop an IC score applying a formative approach and assess its validity.

Methods
The study sample (n = 1908) consisted of 57–88-year-old participants from the Longitudinal Aging Study Amsterdam (LASA). We used logistic regression models to select the indicators to the IC score with 6-year functional decline as an outcome. An IC score (range 0–100) was constructed for each participant. We examined the known-groups’ validity of the IC score by comparing groups based on age and number of chronic diseases. The criterion validity of the IC score was assessed with 6-year functional decline and 10-year mortality as outcomes.

Results
The constructed IC score included seven indicators covering all five domains of the construct. The mean IC score was 66.7 (SD 10.3). The scores were higher among younger participants and those who had lower number of chronic diseases. After adjustment for sociodemographic indicators, chronic diseases, and BMI, a one-point higher IC score was associated with a 7% decreased risk for 6-year functional decline and a 2% decreased risk for 10-year mortality.

Conclusions
The developed IC score demonstrated discriminative ability according to age and health status and is associated with subsequent functional decline and mortality.

Keywords: older people; ageing; functional capacity; measuring instruments (indicators); validity

Free keywords: functional ability; healthy aging; measurement; WHO

Fields of science: