A1 Journal article (refereed)
The development of intrinsic capacity measures for longitudinal research : The Longitudinal Aging Study Amsterdam (2024)
Qi, Y., Schaap, L. A., Schalet, B. D., Hoogendijk, E. O., Deeg, D. J., Visser, M., Koivunen, K., Huisman, M., & van Schoor, N. M. (2024). The development of intrinsic capacity measures for longitudinal research : The Longitudinal Aging Study Amsterdam. Experimental Gerontology, 197, Article 112599. https://doi.org/10.1016/j.exger.2024.112599
JYU authors or editors
Publication details
All authors or editors: Qi, Yuwei; Schaap, Laura A.; Schalet, Benjamin D.; Hoogendijk, Emiel O.; Deeg, Dorly J.H.; Visser, Marjolein; Koivunen, Kaisa; Huisman, Martijn; van Schoor, Natasja M.
Journal or series: Experimental Gerontology
ISSN: 0531-5565
eISSN: 1873-6815
Publication year: 2024
Publication date: 09/10/2024
Volume: 197
Article number: 112599
Publisher: Elsevier
Publication country: United Kingdom
Publication language: English
DOI: https://doi.org/10.1016/j.exger.2024.112599
Publication open access: Openly available
Publication channel open access: Open Access channel
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/97435
Abstract
The World Health Organization has introduced the construct of intrinsic capacity (IC) as an important component of healthy ageing and overall well-being in older adults The present study aimed to develop domain-specific and composite IC scores and to validate these scores by examining their longitudinal relation with functioning.
Methods
We used prospective data on participants aged 57 to over 90 years, with a 10-year follow-up, from the Longitudinal Aging Study Amsterdam, an ongoing cohort study of older Dutch men and women Using a formative, stepwise approach, we identified indicators across the different domains of IC, i.e. vitality, sensory, cognition, psychology, and locomotion, using a combination of unidimensional factor analyses and Partial Least Squares Structural Equation Modelling (PLS-SEM). Next, domain-specific and composite IC scores were generated, and the construct validity (score across age groups) and criterion validity (relationship with change in functional limitations) were assessed.
Results
The multiple unidimensional factor analyses and PLS-SEM identified a total of 18 indicators, covering the five domains of IC. The mean composite IC score was 70.9 (SD = 0.9) in men and 69.7 (0.8) in women. The domain-specific and composite IC scores all showed good construct validity, with known-group validation results indicating age-related declines. A higher composite IC score was associated with less functional limitations over time (B = 0.20, 95%CI [0.19, 0.22]).
Conclusion
The developed domain-specific IC scores and the composite IC score effectively discriminated age-related declines in IC. Additionally, the composite IC score was longitudinally associated with functional limitations. By creating this comprehensive and reliable tool for tracking IC, we aim to provide valuable insights into the dynamics of ageing and support more effective strategies for promoting health and well-being throughout later life. These scores establish a foundation for future research to track longitudinal changes across various IC domains and relate these changes to key age-related outcomes.
Keywords: ageing; old age; intrinsic motivation; mental functioning; social functioning; physical functioning; research methods; longitudinal research; gerontology
Free keywords: intrinsic capacity: longitudinal measures: ageing; formative model
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Ministry reporting: Yes
Preliminary JUFO rating: 1
