Towards a multidimensional healthy ageing phenotype

There is great interest in developing tools to measure healthy ageing and to identify early stages of health impairment, which may guide the implementation of interventions to prevent or delay the development of disease, disability, and mortality. Here, we review the most recent developments directed to operationalize, and test, definitions of healthy ageing.

There is lack of consensus about how to define healthy ageing and, unsurprisingly, diversity in the instruments for its measurement. However, progress is being made in describing and in devising tools to capture the healthy ageing phenotype. Attempts to measure healthy ageing have relied primarily on cross-sectional data collected in older people. More recent studies have assessed the healthy ageing phenotype using markers of multiple functional domains and have used longitudinal data to model the dynamics and trajectories of healthy ageing.

Given the complexity of the ageing process, no single measure is able to predict the ageing trajectory. Current attempts to operationalize the healthy ageing phenotype have relied on markers and data from earlier cohort studies and are limited by the tools used to collect data in those studies. Such data are often unsuitable to detect early subtle declines in function and/or are inappropriate for use in younger old adults. Future studies employing more objective and novel markers of healthy ageing are likely to offer opportunities to define and operationalize the healthy ageing phenotype.