Chronological age, marked by dates and measured by the passage of time, does not always reveal the state of a person's organism, and is incapable of showing by itself how much it has aged or been preserved. To capture the heterogeneity of the elderly population, the World Health Organization (WHO) proposed, in a 2015 report, a new indicator: the intrinsic capacity (IC), a holistic concept that aims to better understand the pathways of aging.

Taking into account physical and mental capacities that are fundamental for keeping active lives, IC comprehends five domains: cognitive, psychological, sensory, locomotor, and vitality. In this context, a new study led by the Laboratory of Medical Investigation in Aging (LIM/66), of the Faculdade de Medicina da Universidade de São Paulo (FMUSP), has confirmed the validity and reliability of IC in measuring healthy aging in Brazil. The findings were published in May in the journal Lancet Regional Health - Americas.

"Our work is the first to validate this indicator in a large population sample of Brazilian adults. In this study we showed that intrinsic capacity is associated with the maintenance of functionality", says Prof. Claudia Kimie Suemoto, Associate of the Geriatrics Discipline at FMUSP.

The analysis included data from 7,175 participants aged 50 years and over from the Longitudinal Study on the Health of the Brazilian Elderly (ELSI-Brasil). The indexes of the IC domains were determined through questionnaires and physical performance tests. In general, individuals had a heterogeneous health status and chronological age was shown to be insufficient to determine their well-being status.

"Our findings demonstrate that intrinsic ability is weakly associated with chronological age, indicating that even older individuals can remain healthy, independent, and active," says Dr. Márlon Aliberti, LIM/66 researcher at FMUSP.

The study also concluded that IC is most strongly related to independence in activities of daily living (ADL) such as dressing and bathing, instrumental activities (IADL) such as shopping and food preparation, and advanced activities (AADL) such as hobbies and work. "Intrinsic ability, more than chronological age, captures what matters most to people's health as they age," says Dr. Liberate.

The next steps, according to the researcher, should include establishing a simpler measure that can be widely implemented in clinical practice, and exploring the interactions between intrinsic capacity and sociodemographic factors.