Editorial

 

John Beard, PhD - Irene Diamond Professor of Productive Aging (in Health Policy Management, Epidemiology and in the Robert N. Butler Columbia Aging Center) and Director of the International Longevity Center USA at CUMC – New York, NY (United States)

 

Intrinsic Capacity: Making Health the Core Outcome of Healthspan Research

Major advances in geroscience, systems biology, and artificial intelligence—combined with unprecedented access to large, deeply phenotyped datasets—mean that for the first time in human history, we may be able to measure health directly, rather than infer it from the presence or absence of disease. Doing so could enable earlier detection of age-related declines and catalyze new interventions to extend healthy longevity. But this shift will require a clear and operationalizable definition of “health” and rigorous methods to assess it.

The World Health Organization’s (WHO) healthy ageing framework, introduced in the World Report on Ageing and Health (2015), provides a compelling foundation.  Rather than focus on the absence of disease, the WHO model frames health from the perspective of functioning.  A core construct of this framework is intrinsic capacity - “the composite of all the physical and mental capacities of an individual.” 

As a measure of individual level functioning, intrinsic capacity could become a transformative outcome for geroscience research, clinical practice, and population health.  Functioning is the health outcome most valued by older adults, so IC has direct relevance to their lived experience. IC is also a continuous outcome enabling monitoring of trajectories over time and early detection when these veer from norms.  Trials of interventions looking to influence trajectories would require far shorter followup periods than might be required for disease-based outcomes.   Moreover, people age even in the absence of disease.  While most biological research has tended to overlook these non disease-related declines, measurement of IC provides a mechanism to explore the biological drivers of these universal changes.

Yet the promise of IC will not be realized without conceptual clarity, measurement rigor, and alignment across biological, clinical, and public health domains.

 

History of the Intrinsic Capacity Construct

The World Report sought to establish a public health framework for healthy ageing that countered persistent stereotypes of older people as dependent and homogeneous—either “deserving poor” or “greedy geezers.” Guided by a capabilities approach and life-course perspective, healthy ageing was defined as “the process of developing and maintaining the functional ability that enables wellbeing.” This ability was described as arising from the intrinsic capacity of the individual, relevant environmental characteristics, and the interaction between the individual and their environment. To shift policy away from chronological age, the report proposed three broad target groups: high and stable capacity, declining capacity, and significant loss—an approach that has shaped global policy.

From the outset, however, intrinsic capacity has been interpreted inconsistently. The WHO model aimed to be consistent with, but not duplicate, the International Classification of Functioning, Disability and Health (ICF) which uses the term capacity to describe performance in a standard environment. But the World Report introduced “intrinsic capacity” as a new construct to emphasize the broad individual-level attributes that might contribute to functional ability, including biological features that might not be observable as performance. While this ambiguity was acceptable in a policy context, it has become problematic as IC is increasingly applied in clinical care and biological research.

WHO undertook a parallel initiative alongside the writing of the Report – “the development of guidelines on interventions to prevent and slow declines in physical and mental capacities in older people at community level”.  This comprised an extensive series of literature reviews of key characteristics considered in clinical practice to be common indicators of “declines in physical and mental capacity”: mobility loss, vision and hearing loss, malnutrition, cognitive declines and depressive symptoms. These reviews were considered by a large panel of experts to assess the quality and strength of evidence for each possible intervention.  While much of this work predated the World report, the findings were ultimately released in 2017 and renamed to be consistent with the World report as “Integrated Care for older people.  Guidelines on community-level interventions to manage declines in intrinsic capacity.”  They formed the basis for WHO’s ongoing integrated care for older people program (ICOPE), which uses a screening assessment of IC as the entry point for integrated clinical care. Early results of studies testing the implementation of this intervention suggest it is likely to be effective.¹  

Yet ICOPE was designed for case-finding, not for measuring IC across the adult life course or capturing subclinical change. Like measures of disease, frailty or deficits in activities of daily living, the ICOPE assessment provides limited information on the gradual declines that may have occurred before significant deficits become apparent.  Nor does it account for correlations between the various subdomains of capacity when calculating a summary IC score.  Its vitality domain is particularly limited, relying solely on nutrition screening, despite the handbook’s broader definition of vitality as encompassing metabolic, neuromuscular, immune, and stress-response functions.²  Despite its clinical utility, the ICOPE screen has uncertain sensitivity, specificity, and prognostic value and does not account for correlations across domains or capture the gradual declines that precede overt impairment.^3-5  

Toward a Structured Measurement Model

In 2017, WHO-affiliated investigators mapped IC to the ICF, identifying five subdomains—locomotor, cognitive, sensory psychological and vitality—as “pivotal” to intrinsic capacity. While the first four comprise overt measures of functioning consistent with traditional ICF approaches to capacity, vitality was conceptualized as describing the biological attributes required to maintain homeostasis. Empirical validation followed in 2019, demonstrating strong predictive validity for care dependence independent of age, socioeconomic status, and multimorbidity. Notably, vitality emerged within these biological analyses with a biologically grounded profile, including DHEAS, IGF-1, hemoglobin, FEV1, and grip strength. This 5 subdomain pattern (with variation in the specific measures used) has since been replicated in cohorts across continents and found to predict subsequent mortality and incidence of specific diseases.

Yet despite broad acceptance of the five-domain structure, methodological inconsistency remains high. Studies differ in scoring approaches, data sources, and measurement tools, particularly for vitality. As IC increasingly becomes a candidate outcome for clinical trials and aging biology studies, lack of standardization poses serious risks—misinterpretation, non-comparability, and potential loss of credibility.

Realizing the Potential of Intrinsic Capacity

To unlock IC’s transformative potential, several actions are urgent:

1. Establish Standardized Measurement Tools

IC measurement must be fit-for-purpose. ICOPE remains valuable as a clinical entry point, but it is not so useful for clinical or epidemiologic research.  Conversely, research approaches built on complex aging cohorts lack scalability and by necessity depend on measures collected for other purposes. We need parsimonious, sensitive, and adaptable measures that capture early change and work in diverse settings. Machine learning may accelerate their development.

2. Update Functional Assessments for the 21st Century

Many current IC measures were designed to diagnose geriatric syndromes and suffer from ceiling effects. New tools—gamified cognition platforms, sensor-based locomotor measures, digital mood and fatigue monitoring—are needed to detect subtle trajectory shifts.

3. Clarify the Role of Self-reported vs. Objective Measures

Large cohort studies often lack physical or cognitive performance data. Harmonized approaches—and validation studies—are needed to integrate subjective and objective measures without sacrificing validity.

4. Prioritize Trajectories, Not Snapshots

IC level and IC decline are likely to have distinct determinants. The intercept of IC trajectories reflects life-course accumulation of capacity; the slope reflects aging processes and modifiable risk. Healthy aging research—and policy—must target change over time (i.e. the slope), not static scores.  The use of continuous measures like IC will also require different analytical approaches than have been traditionally used for disease-based outcomes.

5. Develop Biomarkers Anchored in IC Trajectories

Biomarkers linked to static IC scores are useful but are essentially surrogates. Biomarkers linked to rates of decline are more likely to identify biological mechanisms of aging and respond to geroscience interventions. Dried blood spots and other scalable biospecimens could support population-level adoption.

6. Leverage Genomics and Epigenomics

GWAS and EWAS of IC trajectories are already yielding biologically plausible pathways. Extending this work offers opportunities for interventions outside traditional disease paradigms.

Conclusion

Intrinsic capacity provides a unified lens through which to understand, measure, and ultimately improve human health across longer lives. Interest is exploding—over XXX papers used the construct in 2024—and investment is accelerating. But momentum alone is insufficient. Without measurement rigor, conceptual clarity, and translational alignment, IC risks becoming yet another promising but fragmented framework.

To change the future of aging, we must finish the foundational work: standardize measurement, modernize tools, embed biological insight, and prioritize trajectories. IC offers the possibility to reclaim health—not disease—as the fundamental outcome of ageing. We should not squander that opportunity.

 

 

1             Liu, W. et al. Effectiveness of Integrated Care for Older Pepole (ICOPE) in Improving Intrinsic Capacity in Older Adults: A Systematic Review and Meta‐Analysis. Journal of clinical nursing 34, 1013-1031 (2025).

2             Organization, W. H. Integrated care for older people (‎ICOPE)‎: guidance for person-centred assessment and pathways in primary care. 2nd edn,  (World Health Organization, 2025).

3             Rodríguez-Laso, Á., García-García, F. & Rodríguez-Mañas, L. The ICOPE intrinsic capacity screening tool: measurement structure and predictive validity of dependence and hospitalization. The Journal of nutrition, health and aging 27, 808-816 (2023).

4             Rojano i Luque, X. et al. Identification of decreased intrinsic capacity: Performance of diagnostic measures of the ICOPE Screening tool in community dwelling older people in the VIMCI study. BMC geriatrics 23, 106 (2023).

5             Lu, F. et al. Diagnostic performance analysis of the Integrated Care for Older People (ICOPE) screening tool for identifying decline in intrinsic capacity. BMC geriatrics 23, 509 (2023).