Measuring functional ability in Healthy Ageing: testing its validity using Japanese nationwide longitudinal data

Area of Science:

• Gerontology
• Public Health
• Sociology

Background:

• The UN Decade of Healthy Ageing emphasizes functional ability for monitoring progress.
• Functional ability encompasses an individual's capacity to engage in valued activities across five domains.
• This study investigates the construct validity, cross-validation, and predictive power of functional ability for well-being.

Purpose of the Study:

• To examine the construct validity of functional ability domains.
• To cross-validate functional ability domains using longitudinal data.
• To assess the predictive capacity of functional ability for subsequent well-being in older adults.

Main Methods:

• Utilized panel data from 35,093 community-dwelling Japanese adults aged 65 and above.
• Performed factor analyses on data from 2013 and 2016 to explore functional ability domains.
• Employed modified Poisson regression to associate functional ability domains with well-being in 2019.

Main Results:

• A three-factor model of functional ability, comprising 24 items, was identified and validated across both 2013 and 2016 data.
• The identified domains were: relationship building/maintenance, meeting basic needs/mobility, and learning/decision-making/contribution.
• All three validated functional ability domains significantly predicted subjective health and happiness in 2019.

Conclusions:

• Empirical evidence from Japan supports the conceptualization of functional ability in older populations.
• The study highlights the importance of functional ability as a key indicator for healthy ageing.
• Cross-national validation of the functional ability concept is recommended to support global healthy ageing strategies.