# The Concept of Health, From Definition to Measurement and the Implications of the Reserves-Based Model for Nursing in France

Camille Joannès, Fanny Crozes, Michelle Kelly-Irving, Cyrille Delpierre, Sébastien Couarraze

► To cite this version:

Camille Joannès, Fanny Crozes, Michelle Kelly-Irving, Cyrille Delpierre, Sébastien Couarraze. The Concept of Health, From Definition to Measurement and the Implications of the Reserves-Based Model for Nursing in France. Journal of Advanced Nursing, 2025, 81 (5), pp.2739-2747. 10.1111/jan.16555. hal-04744380

HAL Id: hal-04744380

https://hal.science/hal-04744380v1

Submitted on 18 Oct 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
DISCURSIVE PAPER

OPEN ACCESS

# The Concept of Health, From Definition to Measurement and the Implications of the Reserves-Based Model for Nursing in France

Camille Joannès¹

<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

Fanny Crozes¹,²

Michelle Kelly-Irving¹

Cyrille Delpierre¹

Sébastien Couarze³

¹EQUITY Research Team, Center for Epidemiology & Research in POPulation Health (CERPOP), UMR 1295, University Toulouse III Paul Sabatier, Toulouse, France | ²Institute of Nursing Training, Toulouse University Hospital, Toulouse, France | ³Department of Medicine, Maieutics and Paramedicine, Faculty of Health, AGING Research Team, Center for Epidemiology & Research in POPulation Health (CERPOP), UMR 1295, University Toulouse III Paul Sabatier, Toulouse, France

**Correspondence:** Camille Joannès (camille.joannes@univ-tlse3.fr)

**Received:** 29 April 2024

| **Revised:** 11 September 2024

| **Accepted:** 4 October 2024

**Funding:** The authors received no specific funding for this work.

**Keywords:** health | nursing theory | population health | research methods

## ABSTRACT

**Aim:** To discuss a reserves-based model of Health, recently developed in the literature, defining Health and moving from conceptual considerations to methods of measuring Health, applicable to nursing practice and research.

**Design:** Discursive paper.

**Methods:** A discursive paper critically synthesising a reserves-based model of Health for conceptualising and operationalising Health, with reference to key Health theories from nursing science and social epidemiology.

**Results:** In the reserves-based model of Health, Health was defined as the ability to maintain/restore physical, socioemotional, cognitive and physiological health reserves in order to adapt and self-manage to life's challenges. Health was measured by the sum of indicators of deterioration of health reserves.

**Conclusion:** The reserves-based model of Health defining Health through the prism of adaptation reinforces the holistic vision of Health, appropriate to nursing practice, based on the interconnectedness of the whole person and the whole system.

**Implications for the Profession and Patient Care:** This reserves-based model of Health is likely to modify nursing practices. Nursing diagnosis of patient adaptation could be implemented, in order to offer support care adapted to the patient's capacity to adapt, enabling health promotion strategies to be developed. Nursing research on health reserves is a future promising direction to act on individuals' capacity to adapt.

## 1 | Introduction

France is currently experiencing a major turning point in the evolution of the nursing profession and the field of nursing science. The nursing profession has been reshaped, with the autonomy of advanced practice nursing aimed at developing high-level competencies. These include education, prevention, screening activities, technical and clinical monitoring procedures,

and the ability to make prescriptions (Colson, Galfout, and Schwingrouber 2024; Décret N° 2018-629 Du 18 Juillet 2018 Relatif à l'exercice Infirmier En Pratique Avancée 2018). Nursing science has been integrated into the university setting, which implies the recognition and development of academic careers in nursing sciences (Colson et al. 2021). A new reform, expected shortly, aims to expand nursing competencies for example by emphasising key missions in prevention. It also plans to update

<footnote>This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.</footnote>

<footnote>© 2024 The Author(s). Journal of Advanced Nursing published by John Wiley & Sons Ltd.</footnote>
the training curriculum, emphasising the acquisition and dis-
semination of research, the production of evidence-based data
and the implementation of projects focussed on community and
population health. Furthermore, the reform is designed to en-
hance career progression and development. The current French
political circumstances have led to the postponement of certain
deadlines to at least 2025. Nevertheless, the nursing community
has high expectations for these reforms. Health is therefore a
central focus in the redefinition of nursing education and the
profession. Considering this changing context, the question of
Health in relation to nursing science is addressed in this discur-
sive paper.

Health is at the core of nursing activity and, consequently,
is a fundamental concept in the field of nursing research
(Fawcett 1984). However, the concept of Health does raise sev-
eral issues. First, it has an ambiguous meaning. What does
Health actually mean? A recent scoping review found that there
is a wide variety of concepts of Health, with numerous sub-
themes (van Druten et al. 2022). Therefore, it would be valuable
to investigate the evolution of the definition of Health across
various disciplines, including nursing, to identify their strengths
and limitations. Second, the operationalisation of the concept of
Health in care practice and research. How to measure Health?
Converting this abstract concept into a measurable observation
will make it easier to transpose the concept of Health into rou-
tine care. The challenge of this specific measure would be to
guide care practices in a more appropriate way to suit patients'
needs. Thus, it is essential to establish an operational definition
of Health to move from concept to practical measurement in
nursing practice and research.

In this discursive paper, we aimed to discuss a reserves-based
model of Health recently developed in the literature, by encom-
passing the definition of health and transitioning from concep-
tual considerations to methods of measurement, applicable to
nursing practice and research.

## 2 | Background

Over the last few decades, the concept of Health has broadened
and become more complex, while simultaneously knowledge
about people being cared for has increased. Within the para-
digm of categorisation, the biomedical definition of Health spec-
ifying Health as the absence of disease and disability, has been
most widely used in medical care and research. In this way, the
concept of Health is mainly defined in terms of the absence of
illness, and Health is characterised not by its own inherent at-
tributes where ‘Health is nothing positive, it is simply not being
ill’ (Herzlich 1969). This definition of Health implies identifying,
isolating and treating the root cause of illnesses, as well as tack-
ling the lethal factors involved. The nursing practices associated
with this approach involve recognising the signs and symptoms
that indicate the evolution of the disease, participating in the
treatment administration and monitoring of the patient’s con-
dition (Lecordier 2011). However, this definition of Health has
several limitations due to the categorisation of individuals as
sick or not, resulting in classification biases that have long been
recognised (Amzat and Razum 2014; Boorse 1977). This thresh-
old for classifying individuals does not include the multiple

symbolic values that accompany the concept of illness, which
vary according to the dominant culture, civilisation and histor-
ical period (Ereshefsky 2009; King 1954). This model therefore
leads to confusion between Health and medicine, the assimila-
tion of which is too narrow to define Health.

In 1946, The World Health Organization defined Health as ‘a
state of complete physical, mental and social well-being and
not merely the absence of disease or infirmity’ (World Health
Organization 1946), with the aim of guiding national and global
health governance. However, the utopian and unmeasurable
nature of Health related to the absolute nature of the term
‘complete’, in relation to ‘well-being’, can lead to the mistaken
assumption that almost all individuals are ill (Huber et al. 2011;
Larson 1996; Leonardi 2018), particularly with the ageing pro-
cess. Furthermore, this definition does not consider the living
conditions and the multiple factors surrounding individuals that
are components of Health.

Within the paradigm of integration, Health was then broadened
by considering it holistically, recognising the complexity of the
environment surrounding individuals, as represented by the
Dahlgren-Whitehead model (Dahlgren and Whitehead 1991).
This model considers Health associated with the individual's en-
vironment (Pépin, Ducharme, and Kérouac 2017) and consisting
of health determinants distributed at the individual, meso and
macro levels. These health determinants are the 'conditions in
which people are born, grow, work, live, and age, and the wider
set of forces and systems shaping the conditions of daily life'
(Commission on Social Determinants of Health 2008). The nursing practices associated with this approach place greater emphasis on understanding people, their values, lifestyles, history and culture, and involve cooperation within a multidisciplinary team of carers. However, while it seems promising to define the specificity of Health in a multidimensional way (mental, social and well-being) and in relation to the external environment surrounding individuals, these definitions of Health downplay the role of individual capacities to overcome life's challenges and live well despite chronic illness or disability.

Within the transformation paradigm with the aim of achieving
harmony of body and mind, the ability of individuals to cope
with their environment and to self-manage has been recognised
in the Ottawa Charter (World Health Organization 1986). In
Nursing Sciences, early theories of Health and adaptation, no-
tably Roy's adaptation model (Roy 1997), provided a robust and
comprehensive theoretical framework. Roy's adaptive model
posits that the individual can be conceptualised as an integrated
whole, engaged in a constant interaction with the environment.
This model further suggests that the individual's coping mech-
anisms can be enhanced through the implementation of nursing interventions (Callis 2020; Mansouri et al. 2019; Roy 2011).
The nursing practices associated with this approach are moving
away from the omnipotence of the carer, towards the engage-
ment of nurses in health promotion and education, supporting
individuals to solve their own health issues. In line, with Roy's
adaptation model, Huber and colleagues proposed in 2011 an al-
ternative definition of Health centred on individuals and their
ability to adapt, as follows: Health is 'the ability to adapt and
self-manage in the face of social, physical and emotional chal-
lenges' (Huber et al. 2011). Specifically, an individual's health
is understood when their psychological organisation, organism or social participation can implement a protective response to restore equilibrium in the face of social, physiological or psychological stress. This consideration of Health as the ability to cope has grown increasingly popular in recent years. However, it should be emphasised that this ability is not identical between individuals. Indeed, an individual who is born, grows up and lives in an environment with many stressors will not have the same type of adaptation during his or her life as an individual evolving in a more protective environment with more resources that can be used immediately for the needs of daily life (Cullati, Kliegel, and Widmer 2018). To address interindividual differences in adaptation, the concept of health reserves has been recently developed by Cullati and colleagues. Health reserves are latent capacities with a protective function to adapt and cope with adverse life events, and maintained by a sufficient quantity of resources (Cullati, Kliegel, and Widmer 2018). Figure 1 presents a schematic representation of health reserves as a means of adapting Health.

## 3 | Overview of the Issue

This synthesis of key health theories in nursing sciences and social epidemiology to conceptualise Health has raised the interest of conceptualising it through the lens of adaptation. This perspective shifts away from solely focusing on the aetiology of diseases—examining symptoms, syndromes and systemic causes—towards a holistic conception of Health, emphasising the interrelation between individuals and their environment. The concept of health reserve has been found to be an effective way of addressing individual differences in the ‘ability to adapt and self-manage’. The first issue is therefore to link these different conceptualisations around a single definition of Health, that is, to integrate the concept of health reserves into the definition of Health as an adaptive capacity. The second issue is to move from conceptual considerations to defining methods of measuring Health. Addressing these two issues would then provide a

Health framework applicable to nursing practice and research. This discursive paper will present and discuss a reserves-based model of Health recently developed in the literature (Joannès et al. 2023) that addressed these issues.

## 4 | Results

### 4.1 | Definition of Health in the Reserves-Based Model

In the light of the conceptual evolution in the definitions of Health, the reserves-based model of Health has defined Health through the prism of adaptation (Huber et al. 2011) and further developed it by incorporating the concepts of reserves developed by Cullati and colleagues (Cullati, Kliegel, and Widmer 2018). The definition of Health used was the individual's ability to maintain or restore health reserves in order to adapt and self-manage to social, physical and emotional challenges (Joannès et al. 2023). Health reserves have been identified as physical, socioemotional, cognitive (Ben-Shlomo 2013) and physiological (Lu, Pikhart, and Sacker 2019). Table 1 presents the description of each health reserve.

### 4.2 | Reserves-Based Model Method for Measuring Health

This consideration of Health through adaptation means that if the presence of adaptation (p) implies optimal health (q), then impaired health (not p) necessarily implies compromised adaptation (not q), and vice versa. Given the complexity of measuring adaptation itself, the reserves-based model chose to measure it through its contrapositive, that is, a compromised adaptation, also called accommodation (Frisancho 1993). It has been assumed that accommodation generates a cost on health reserves. This cost on health reserve could be observable in mid-life, after the build-up phase during the youth and before the

<figure><img src="image_4.png" /><figcaption>**FIGURE 1** | Schematic representation of the concept of reserves extracted from the study of Cullati S. and al. (Cullati, Kliegel, and Widmer 2018). The level of reserves is illustrated by the blue and orange lines. The blue line (A) represents the situation of a successful adaptation to adverse life events. The orange line (B) represents a situation of a compromised adaptation to adverse life events, leading to vulnerability.</figcaption></figure>
<table><caption>TABLE 1 | Description of health reserves and example of indicators of measurement.</caption><thead><tr><th>Health reserve</th><th></th><th>Examples of indicators of deteriorating health reserves</th></tr></thead><tbody><tr><td>Physical reserve</td><td>Refers to an individual's intrinsic physical or functional capacity of body functions, accumulated over a lifetime, to carry out physical activities. It aims to maintain functional integrity and contributes to an adaptive response to environmental physical challenges (Kuh et al. 2014)</td><td><ul><li>Chronic pain or Chronic Widespread Pain (Jones et al. 2007; Jones, Power, and Macfarlane 2009)</li><li>Grip strength (Sayer and Kirkwood 2015)</li><li>Standardised physical mobility tests (Soubra, Chkeir, and Novella 2019)</li></ul></td></tr><tr><td>Socio-emotional reserve</td><td>Characterises the intrinsic ability, built up throughout life and influenced by social and cultural factors, to cope with an emotional and social stressor (Ben-Shlomo, Cooper, and Kuh 2016; Lu, Pikhart, and Sacker 2019)</td><td><ul><li>Clinical Interview Schedule (CIS-r) (Lewis et al. 1992)</li><li>Malaise inventory (Scully 2014)</li><li>Schedule for Clinical Assessment in Neuropsychiatry (SCAN) (Wing et al. 1990)</li></ul></td></tr><tr><td>Cognitive reserve</td><td>Corresponds to the 'level of protection against the clinical manifestations of neurological damage', that is, the capacity accumulated throughout life to maintain and improve cognitive functioning in order to delay its decline due to ageing (Stern 2009)</td><td><ul><li>Patient Health Questionnaire (PHQ) (Kroenke, Spitzer, and Williams 2001)</li><li>Hamilton Anxiety and Depression Scale (Ham-A and Ham-D) (Maier et al. 1988)</li><li>Other validated screening instrument assessing psychological distress</li></ul></td></tr><tr><td>Physiological reserve</td><td>Related to the concept of allostasis, an active process by which the body attempts to maintain normal physiological regulation in response to stress (Sterling and Eyer 1988) and avoid physiological imbalances across systems</td><td><ul><li>The Trail Making test A and B (Ciolek and Lee 2020)</li><li>Cognitive Reserve Index questionnaire (Nucci, Mapelli, and Mondini 2012)</li><li>Montreal Cognitive Assessment (MoCA) test (Nasreddine et al. 2005)</li><li>Other validated cognitive assessment</li></ul></td></tr></tbody></table>

natural decline phase of later life, as can be expected with aging and the progressive loss of functional and cognitive abilities as illustrated by the Strachan-Sheikh Model (Blane et al. 2013; Kuh and Ben-Shlomo 2004). The assumption is that the cost on health reserves can be then measured by indicators of health reserve deterioration. According to the definition adopted, four health reserves were retained, that is, physical, socioemotional, cognitive and physiological reserves. Indicators of deteriorating health reserves were considered to be clinical symptoms or validated measures of chronic wear and tear corresponding to health reserves. A list of nonexhaustive indicators of deteriorating health reserves that could be available and used in care practice to measure Health has been provided (Table 1).

Once a set of indicators has been selected, this reserves-based model proposed to combine them by summing them to construct a measure of overall Health. Assuming that each indicator had the same weight as the others, each indicator was given a uniform weight. The overall Health measure can then be classified into three categories: 'Optimal/Medium/Impaired'. The 'Optimal' corresponds to the absence of values taken by

indicators indicating a potential health risk or wear and tear. The 'Medium' corresponds to the presence of a value taken by an indicator indicating a potential health risk or wear and tear. The 'Impaired' category corresponds to the presence of two or more values taken by indicators indicating a potential health risk or wear and tear.

## 4.3 | Application of the Reserves-Based Model Method to Measure Health Within a Cohort

An application of the reserves-based model was performed using data of 9377 subjects from the UK birth cohort *National Child Development Study* (NCDS 58). The data used were those collected when the individuals were aged between 44 and 45, through a biomedical survey (blood and saliva samples and anthropometric measurements) and a home clinical assessment. A measure of overall Health in middle adulthood was obtained with the identification of indicators of deterioration in health reserves. The indicators selected were *allostatic load* (AL) for physiological reserve, *chronic widespread pain* (CWP)
for physical reserve and the *clinical interview schedule-revised* (CIS-r) for socioemotional reserve. No indicator of cognitive reserve was available in the data set. Each indicator was reformatted so that their categories varied from 0 to 1. The overall measure of Health was constructed by summing the previously selected indicators. The overall health measure was then categorised into three groups: 'Optimal/Medium/Impaired' based on the hypothetico-deductive methodology developed previously: the 'Optimal' category corresponded to the absence of health risk value taken by AL, CWP and CIS-r; the 'Medium' category corresponded to the presence of one health risk value taken by AL, CWP and CIS-r; the 'Impaired' category corresponded to the presence of two or more values taken by AL, CWP and CIS-R. Table 2 illustrates the construction of the overall health measure according to the categories of each selected indicator.

The criterion validity of the overall Health measure was examined by modelling the relationship between the overall Health measure and subsequent mortality as well as later self-rated health, first using logrank tests or Chi square, then logistic regressions or Cox proportional regression, as appropriate. Statistical modelling found that individuals with an impaired overall Health were at greater risk of dying or reporting poor perceived health over a 14-year period following the initial overall Health measure.

The robustness of the method was assessed using comparative analyses. A further grouping of the general health measure indicated that the observed results did not depend on the categorisation of the general health measure. Another choice of health reserve indicator reported that the observed results were not biased by the variables constituting the overall Health measure. Random subsamples of the data using a negative control variable were set up and revealed the results observed were not biased by the data of the initial sample.

## 5 | Discussion

### 5.1 | Summary of the Findings and Comparison With Other Health Models

The reserves-based model has defined Health as the individual's ability to maintain or restore health reserves in order to adapt, and the measurement of Health was based on the identification and summation of indicators of deterioration in health reserves. The measure created from this model based on reserves was found to be a good predictor of subsequent poor perceived health and mortality.

The reserves-based model is in line with holism in nursing sciences (Dossey et al. 2015). Indeed, the reserves-based model considers not only the physical aspects of health but also the emotional, mental and social dimensions of the individual and recognises that these they are interconnected and that imbalances in one dimension can affect the others, which has an impact on the overall measure of health of the reserves-based model. However, the reserves-based model involves dimensionality with the consideration of the socioemotional, physiological, physical, cognitive reserves, which may diverge from holism that considers health from a global perspective. This fragmentation of Health arises from the objective of operationalising the concept of Health for quantitative measurement. Despite this initial fragmentation, the reserves-based model ultimately achieves reunification as the dimensions are reconsidered collectively through the aggregation of each reserve's indicators, leading to a comprehensive measurement of health in its holistic sense.

The reserves-based model is also in line with the adaptation model proposed by Roy, which postulates that individuals adapt to environmental influences, or stimuli, using innate

<table><caption>TABLE 2 | Construction of the overall health measure according to selected indicators.</caption><thead><tr><th colspan="5">Selected indicators</th></tr><tr><th>Allostatic load</th><th>Clinical Interview Schedule revised</th><th>Chronic Widespread Pain</th><th></th><th>Overall health</th></tr></thead><tbody><tr><td>Low</td><td>No mental disorder</td><td>No Chronic Widespread Pain</td><td>↔</td><td>Optimal</td></tr><tr><td>Medium</td><td>No mental disorder</td><td>No Chronic Widespread Pain</td><td></td><td rowspan="2">Medium</td></tr><tr><td>High</td><td>No mental disorder</td><td>No Chronic Widespread Pain</td><td></td></tr><tr><td>Low</td><td>Common mental disorders</td><td>No Chronic Widespread Pain</td><td></td><td rowspan="2">Impaired</td></tr><tr><td>Low</td><td>No mental disorder</td><td>Chronic Widespread Pain</td><td></td></tr><tr><td>Medium</td><td>Common mental disorders</td><td>No Chronic Widespread Pain</td><td></td><td rowspan="2"></td></tr><tr><td>Medium</td><td>No mental disorder</td><td>Chronic Widespread Pain</td><td></td></tr><tr><td>High</td><td>Common mental disorders</td><td>No Chronic Widespread Pain</td><td></td><td rowspan="2"></td></tr><tr><td>Low</td><td>Common mental disorders</td><td>Chronic Widespread Pain</td><td>↔</td></tr><tr><td>High</td><td>No mental disorder</td><td>Chronic Widespread Pain</td><td></td><td rowspan="3"></td></tr><tr><td>Medium</td><td>Common mental disorders</td><td>Chronic Widespread Pain</td><td></td></tr><tr><td>High</td><td>Common mental disorders</td><td>Chronic Widespread Pain</td><td></td></tr></tbody></table>

Note: The grey colour of the initial two rows serves to differentiate the column headings and sub-headings from the subsequent results. The grey arrows indicate the category to which each row of results in the right-hand column belongs.
or acquired adaptation mechanisms, which are biological, psychological and social (Roy 1997). Roy's Adaptation Model implies that the individual adapts to changes in the environment or responds to stimuli using innate or acquired adaptation mechanisms, which are biological, psychological and social. This model is applied in nursing practice whenever a patient suffers from an illness for the first time or experiences a difficulty in their state of health, or faces the end of their life, to give them the means to act and achieve positive results. However, while the reserves-based model studied physical, psychosocial, cognitive and physiological reserves, Roy's model considers modes of adaptation to be 'physiological', 'self-concept', 'role function' and 'interdependence'. These similarities and differences with the model proposed by Roy, on the one hand, reinforce the approach of the reserves-based model in the field of nursing and, on the other hand, open up discussions on its application in the nursing process, particularly when assessing patient's behaviour and reaction to stimuli, and the nursing response in return.

## 5.2 | Limitations

The reserves-based model of Health has its limitations, notably related with the measurement of Health itself.

A first limitation is related to the thresholds chosen. In the current application, the allostatic load indicator used in the construction of the measurement of Health is categorised as low/medium/high based on its statistic distribution within the UK study cohort. The question then arises as to its use in nursing practice if there is no validated 'clinical' threshold for the indicators chosen. Furthermore, the thresholds for defining 'optimal', 'medium' and 'impaired' Health are of major consequences for nursing practice: a change in an individual's health status from 'optimal' to 'medium' Health is of less concern from a change in health status from 'medium' to 'impaired' Health. These issues deserve to be further investigated.

A second limitation is related to the nonexhaustive, and therefore modifiable, list of indicators of health reserve deterioration. This list must be improved, particularly for the use of this concept in nursing practice. It would be of interest to compare the indicators used in the reserves-based model with those used in population studies to measure human Health (OECD Publishing 2023) or those related to quality of life, such as the SF-36 (Ware 2000), or frailty, which are used in research on healthy and successful ageing (Fuellen et al. 2019; Lara et al. 2013; Lu, Pikhart, and Sacker 2019). This list must also be developed when an indicator cannot be measured, as in the present application where the cognitive reserve was not measured as no corresponding indicator was identified. This implied a lack of precision in the validation of the measurement of overall Health with a possible underestimation of the results observed with mortality and perceived health.

A third limitation is related to the absence of differentiated weighting of indicators in the measurement of overall Health. This assumes that each indicator corresponds to a health reserve and that these reserves theoretically play an equivalent role in Health. Defining the precise role that each reserve could have on

the others and on Health is a complex issue when choosing the weighting to be assigned. This reserves-based model, which is relatively simple via the sum of indicators, produces a synthetic measure that has been shown to capture a common variance between its various components.

A last limitation relates to the transferability of the measure of Health. The measure of Health studied was a cross-sectional measure in midadulthood, supposed to reflect the overall Health of the individual. It first raises the question of how this non-prospective measure of Health can be inferred from Health at other ages. The choice of this cross-sectional measure is based both on Krieger's ecosocial theory (Krieger 2001), which postulates that Health at a given age is the consequence of a life-course process affected by all the past experiences, and also on the Strachan-Sheikh Model (Kuh and Ben-Shlomo 2004), which postulates that health follows a trajectory resulting from a build-up followed by a decline phase related to advanced age. However, the measurement of Health in midadulthood between these two phases is only valid for cognitive and motor functions, which follow these trajectories, but not for well-being, which has a U-shaped trajectory over the life course (Blanchflower 2021). This raises the question of the appropriate period of life for measuring socioemotional reserve. Further research is required in nursing science to analyse whether repeated Health measurements provide better information about an individual's holistic Health.

The United Kingdom is home to a distinctive series of birth cohort studies, which provide a unique opportunity to examine health status across the life course and to compare health outcomes with those of non-French-speaking Western health systems. France has a number of databases, including EPP, Gazel, E3N, Paquid, EVA and SNDS. However, it is unclear whether these databases contain sufficiently detailed information to measure health using the reserves-based model. Furthermore, it is uncertain whether nurses can access or collect this information on a routine basis. Discussion and evolution are expected to prioritise the collection of and access to this data.

## 5.3 | Perspectives

This set of limitations opens avenues for discussion between diverse professionals from nursing sciences, medicine, public health, social epidemiology, psychology and philosophy of sciences about the different health models and suggests a more in-depth conceptual analysis to improve the reserves-based model in relation to the theory of adaptation in nursing care. From a nursing science and practice perspective, consideration should be given to translating the reserves-based model at individual level rather than population level. Indeed, the global health measure is currently validated with probability analyses comparing population groups with others, producing averaged results of individual data. The current composite measure of Health, itself based on composite measures such as allostatic load composed of a sum of biomarkers, and the thresholds for these measures initially defined/validated on populations with their own characteristics, requires applied research to help identify and implement pragmatic ways of operationalising this concept in nursing care.
Furthermore, nursing research on the various dimensions that make up these reserves and to study health reserves throughout life is a future promising direction. This could enable to examine the way in which health reserves are built up, maintained and activated over the life course. This could lead to identify factors likely to affect ‘the ability to adapt and self-manage’, and specifically those are likely to ‘restore’ health reserves, thereby contributing to improve health. The identification of the determinants of positive health would make it possible to develop interventions, involving nurses, to enhance individuals' ability to adapt, that is, to act on resilience in health.

Given that health promotion is one of the nursing profession's core missions, the reserves-based model would enable a redefinition of the contours of these missions to carry out potentially more relevant actions according to the forthcoming new French nursing decree. Healthcare practices aligned with the reserves-based model may encompass nursing assessments and diagnosis of a patient's health adaptation, considering their age, sex and levels of health reserve, using indicators of their deterioration through health wear and tear. Through the prism of wear and tear, this approach will make it possible to measure the patient's adaptation to the health consequences of their life course, enabling tailored supportive care based on their specific circumstances. Healthcare professionals' and patients' understanding of the meaning of health reserves will encourage patients' active participation and empowerment, and help avoid misunderstandings in practice (Song and Kong 2015). In addition, the importance of accounting for inequalities in adaptation between individuals enables an equitable approach of care that can addresses social health inequalities.

This approach based on the reserves model can lead to an evolution in practices public health for nursing in France. An example illustrating this evolution is the HIV screening (Leblanc et al. 2018). Prior to 2012, HIV screening in France was nontargeted and performed by doctors in emergency departments for patients with symptoms related to HIV, following a 'population approach'. However, this method was insufficient for early infection detection. A few years later, screening practices evolved into a 'high-risk strategy', with nurses conducting targeted HIV screening based on individual patient characteristics. This approach could further develop into a 'vulnerable population approach', considering individuals' health reserves and implementing targeted actions based on their health adaptation with HIV diagnosis. The paradigmatic evolution of health through adaptation calls for an evolution of nursing practices, which could be taken up by advanced practice nurses with support from the current healthcare system in France in prevention and health promotion, although their political agenda prioritisation is not emphasised. Furthermore, the measures do not exhaust the possibilities for enabling France to benchmark health care outcomes with those of non-Francophone Western healthcare systems. At a time when public policies are increasingly geared towards preventive measures, and when professions are evolving, the way to (re)think about Health is now crucial.

## 6 | Conclusion

The conception of Health through the prism of a coping mechanism reverses the traditional negative way of considering Health

as the presence of disease. This new positive and community-based approach, integrating a holistic dimension of Health, has a strong message based on the identification of factors favouring self-fulfilment (Fowokan et al. 2023). This paradigmatic evolution is not just a conceptual change, it is also likely to profoundly modify the healthcare system through its innovative actions. The role of the various healthcare players, including nurses, can be significantly modified and strengthened by the missions entrusted to them. This broader, and therefore less medical, definition of health strengthens the role of other professions, first and foremost nurses, whose mission is to take into account the patient as a whole, and also to promote health, from the patient's point of view to the person in their environment.

## Conflicts of Interest

The authors declare no conflicts of interest.

## Data Availability Statement

The authors have nothing to report.

## Peer Review

The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer-review/10.1111/jan.16555.

## References

Amzat, J., and O. Razum. 2014. "Health, Disease, and Illness as Conceptual Tools." In *Medical Sociology in Africa*, edited by J. Amzat and O. Razum, 21–37. Switzerland: Springer Nature. https://doi.org/10.1007/978-3-319-03986-2_2.

Ben-Shlomo, Y. 2013. *A Life Course Approach to Healthy Ageing*. Edited by D. Kuh, R. Cooper, R. Hardy, and M. Richards. Oxford: Oxford University Press. https://doi.org/10.1093/acprof:oso/9780199656516.001.0001.

Ben-Shlomo, Y., R. Cooper, and D. Kuh. 2016. "The Last Two Decades of Life Course Epidemiology, and Its Relevance for Research on Ageing." *International Journal of Epidemiology* 45, no. 4: 973–988. https://doi.org/10.1093/ije/dyw096.

Blanchflower, D. G. 2021. "Is Happiness U-Shaped Everywhere? Age and Subjective Well-Being in 145 Countries." *Journal of Population Economics* 34, no. 2: 575–624. https://doi.org/10.1007/s00148-020-00797-z.

Blane, D., M. Kelly-Irving, A. d'Errico, M. Bartley, and S. Montgomery. 2013. "Social-Biological Transitions: How Does the Social Become Biological?" *Longitudinal and Life Course Studies* 4, no. 2: Article 2. https://doi.org/10.14301/llcs.v4i2.236.

Boorse, C. 1977. "Health as a Theoretical Concept." *Philosophy of Science* 44, no. 4: 542–573. https://doi.org/10.1086/288768.

Callis, A. M. 2020. "Application of the Roy Adaptation Theory to a Care Program for Nurses." *Applied Nursing Research* 56: 151340. https://doi.org/10.1016/j.apnr.2020.151340.

Ciolek, C. H., and S. Y. Lee. 2020. "Chapter 19—Cognitive Issues in the Older Adult." In *Guccione's Geriatric Physical Therapy*, edited by D. Avers and R. A. Wong, 4th ed., 425–452. Missouri, USA: Mosby. https://doi.org/10.1016/B978-0-323-60912-8.00019-1.

Colson, S., S. Galfout, and J. Schwingrouber. 2024. "Advanced Practice Nursing in France: A Critical Reflection of the Past Five Years." *Journal of Advanced Nursing* 80: 3003–3005. https://doi.org/10.1111/jan.16134.
Colson, S., A. Muller, L. Visier, B. Vennat, E. Noel-Hureaux, and R. Gagnayre. 2021. "Development of the Nursing Science University Field in France: National and International Perspectives." *Journal of Advanced Nursing* 77, no. 4: 1633-1634. https://doi.org/10.1111/jan.14756.

Commission on Social Determinants of Health. 2008. "Closing the Gap in a Generation: Health Equity Through Action on the Social Determinants of Health: Final Report of the Commission on Social Determinants of Health." *Combler Le Fossé En Une Génération: Instaurer l'équité En Santé En Agissant Sur Les Déterminants Sociaux de La Santé: Rapport Final de La Commission Des Déterminants Sociaux de La Santé* 247. https://iris.who.int/handle/10665/43943.

Cullati, S., M. Kliegel, and E. Widmer. 2018. "Development of Reserves Over the Life Course and Onset of Vulnerability in Later Life." *Nature Human Behaviour* 2: 551-558. https://doi.org/10.1038/s41562-018-0395-3.

Dahlgren, G., and M. Whitehead. 1991. *Policies and Strategies to Promote Social Equity in Health. Background Document to WHO-Strategy Paper for Europe* (2007:14; Arbetsrapport). Stockholm, Sweden: Institute for Futures Studies.

Décret N° 2018-629 Du 18 Juillet 2018 Relatif à l'exercice Infirmier En Pratique Avancée. 2018. https://www.legifrance.gouv.fr/jorf/id/JORFT EXT000037218115.

Dossey, B. M., L. Keegan, C. C. Barrere, and M. A. B. Helming. 2015. *Holistic Nursing: A Handbook for Practice*. Burlington, MA, USA: Jones & Bartlett Publishers.

Ereshefsky, M. 2009. "Defining 'Health' and 'Disease'." *Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences* 40, no. 3: 221-227. https://doi.org/10.1016/j.shpsc.2009.06.005.

Fawcett, J. 1984. "The Metaparadigm of Nursing: Present Status and Future Refinements." *Image: The Journal of Nursing Scholarship* 16, no. 3: 84-87. https://doi.org/10.1111/j.1547-5069.1984.tb01393.x.

Fowokan, A., J. L. Giosa, M. Saari, and P. Holyoke. 2023. "Mapping a Comprehensive Assessment Tool to a Holistic Definition of Health for Person-Centred Care Planning in Home Care: A Modified eDelphi Study." *BMC Health Services Research* 23, no. 1: 1268. https://doi.org/10.1186/s12913-023-10203-5.

Frisancho, A. R. 1993. *Human Adaptation and Accommodation*. Ann Arbor: University of Michigan Press.

Fuellen, G., L. Jansen, A. A. Cohen, et al. 2019. "Health and Aging: Unifying Concepts, Scores, Biomarkers and Pathways." *Aging and Disease* 10, no. 4: 883-900. https://doi.org/10.14336/AD.2018.1030.

Herzlich, C. 1969. *Santé et Maladie. Analyse d'une Représentation Sociale*. 1st ed. Aubervilliers, Paris: École des Hautes Études en Sciences Sociales.

Huber, M., J. A. Knottnerus, L. Green, et al. 2011. "How Should We Define Health?" *BMJ* 343: d4163. https://doi.org/10.1136/bmj.d4163.

Joannès, C., H. Colineaux, G. Guernec, R. Castagné, and M. Kelly-Irving. 2023. "Toward a Conceptual Framework of Health and Its Operational Definition: An Application in the 1958 British Birth Cohort." *BMC Public Health* 23, no. 1: 100. https://doi.org/10.1186/s12889-022-14967-z.

Jones, G. T., C. Power, and G. J. Macfarlane. 2009. "Adverse Events in Childhood and Chronic Widespread Pain in Adult Life: Results From the 1958 British Birth Cohort Study." *Pain* 143, no. 1: 92-96. https://doi.org/10.1016/j.pain.2009.02.003.

Jones, G. T., A. J. Silman, C. Power, and G. J. Macfarlane. 2007. "Are Common Symptoms in Childhood Associated With Chronic Widespread Body Pain in Adulthood?: Results From the 1958 British Birth Cohort Study." *Arthritis & Rheumatism* 56, no. 5: 1669-1675. https://doi.org/10.1002/art.22587.

Karimi, M., R. Castagné, C. Delpierre, et al. 2019. "Early-Life Inequalities and Biological Ageing: A Multisystem Biological Health Score Approach in Understanding Society." *Journal of Epidemiology and Community Health* 73, no. 8: 693-702. https://doi.org/10.1136/jech-2018-212010.

King, L. S. 1954. "What is Disease?" *Philosophy of Science* 21, no. 3: 193-203.

Krieger, N. 2001. "Theories for Social Epidemiology in the 21st Century: An Ecosocial Perspective." *International Journal of Epidemiology* 30, no. 4: 668-677. https://doi.org/10.1093/ije/30.4.668.

Kroenke, K., R. L. Spitzer, and J. B. Williams. 2001. "The PHQ-9: Validity of a Brief Depression Severity Measure." *Journal of General Internal Medicine* 16, no. 9: 606-613. https://doi.org/10.1046/j.1525-1497.2001.016009606.x.

Kuh, D., and Y. Ben-Shlomo. 2004. "A Life Course Approach to Respiratory and Allergic Diseases." In *A Life Course Approach to Chronic Disease Epidemiology*, edited by D. Kuh, Y. Ben Shlomo, and S. Ezra. Oxford: Oxford University Press. https://doi.org/10.1093/acprof:oso/9780198578154.003.0010.

Kuh, D., S. Karunanananthan, H. Bergman, and R. Cooper. 2014. "A Life-Course Approach to Healthy Ageing: Maintaining Physical Capability." *Proceedings of the Nutrition Society* 73, no. 2: 237-248. https://doi.org/10.1017/S0029665113003923.

Lara, J., A. Godfrey, E. Evans, et al. 2013. "Towards Measurement of the Healthy Ageing Phenotype in Lifestyle-Based Intervention Studies." *Maturitas* 76, no. 2: 189-199. https://doi.org/10.1016/j.maturitas.2013.07.007.

Larson, J. S. 1996. "The World Health Organization's Definition of Health: Social Versus Spiritual Health." *Social Indicators Research* 38, no. 2: 181-192. https://doi.org/10.1007/BF00300458.

Leblanc, J., G. Hejblum, D. Costagliola, et al. 2018. "Targeted HIV Screening in Eight Emergency Departments: The DICI-VIH Cluster-Randomized Two-Period Crossover Trial." *Annals of Emergency Medicine* 72, no. 1: 41-53.e9. https://doi.org/10.1016/j.annemergmed.2017.09.011.

Lecordier, D. 2011. "La Santé et les Soins Infirmiers: L'évolution de Concepts Centraux Dans un Contexte Scientifique Donné." *Recherche en Soins Infirmiers* 106, no. 3: 82-85. https://doi.org/10.3917/rsi.106.0082.

Leonardi, F. 2018. "The Definition of Health: Towards New Perspectives." *International Journal of Health Services* 48, no. 4: 735-748. https://doi.org/10.1177/0020731418782653.

Lewis, G., A. J. Pelosi, R. Araya, and G. Dunn. 1992. "Measuring Psychiatric Disorder in the Community: A Standardized Assessment for Use by Lay Interviewers." *Psychological Medicine* 22, no. 2: 465-486. https://doi.org/10.1017/S0033291700030415.

Lu, W., H. Pikhart, and A. Sacker. 2019. "Domains and Measurements of Healthy Aging in Epidemiological Studies: A Review." *Gerontologist* 59, no. 4: e294-e310. https://doi.org/10.1093/geront/gny029.

Maier, W., R. Buller, M. Philipp, and I. Heuser. 1988. "The Hamilton Anxiety Scale: Reliability, Validity and Sensitivity to Change in Anxiety and Depressive Disorders." *Journal of Affective Disorders* 14, no. 1: 61-68. https://doi.org/10.1016/0165-0327(88)90072-9.

Mansouri, A., S. Baraz, N. Elahi, A. S. Malehi, and B. Saberipour. 2019. "The Effect of an Educational Program Based on Roy's Adaptation Model on the Quality of Life of Patients Suffering From Heart Failure: A Clinical Trial Study." *Japan Journal of Nursing Science* 16, no. 4: 459-467. https://doi.org/10.1111/jjns.12255.

McEwen, B. S., and E. Stellar. 1993. "Stress and the Individual: Mechanisms Leading to Disease." *Archives of Internal Medicine* 153, no. 18: 2093-2101. https://doi.org/10.1001/archinte.1993.00410180039004.
Nasreddine, Z. S., N. A. Phillips, V. Bédirian, et al. 2005. "Montreal Cognitive Assessment, MoCA: A Brief Screening Tool for Mild Cognitive Impairment." *Journal of the American Geriatrics Society* 53, no. 4: 695-699. https://doi.org/10.1111/j.1532-5415.2005.53221.x.

Nucci, M., D. Mapelli, and S. Mondini. 2012. "Cognitive Reserve Index Questionnaire (CRIq): A New Instrument for Measuring Cognitive Reserve." *Aging Clinical and Experimental Research* 24, no. 3: 218-226. https://doi.org/10.3275/7800.

OECD Publishing. 2023. *Health at a Glance 2023: OECD Indicators*. Paris, France: OECD Publishing. https://doi.org/10.1787/7a7afb35-en.

Pépin, J., F. Ducharme, and S. Kérouac. 2017. "CHAPITRE 2 L'influence des paradigmes." In *La Pensée Infirmière 4ème Édition* (Chenelière Education, 32).

Roy, C. 1997. "Future of the Roy Model: Challenge to Redefine Adaptation." *Nursing Science Quarterly* 10, no. 1: 42-48. https://doi.org/10.1177/089431849701000113.

Roy, C. 2011. "Research Based on the Roy Adaptation Model: Last 25 Years." *Nursing Science Quarterly* 24, no. 4: 312-320. https://doi.org/10.1177/0894318411419218.

Sayer, A. A., and T. B. L. Kirkwood. 2015. "Grip Strength and Mortality: A Biomarker of Ageing?" *Lancet* 386, no. 9990: 226-227. https://doi.org/10.1016/S0140-6736(14)62349-7.

Scully, C. 2014. "4—Signs and Symptoms." In *Scully's Medical Problems in Dentistry*, edited by C. Scully, 7th ed., 97-122. Kidlington, Oxford, UK: Churchill Livingstone. https://doi.org/10.1016/B978-0-7020-5401-3.00004-7.

Song, M., and E.-H. Kong. 2015. "Older Adults' Definitions of Health: A Metasynthesis." *International Journal of Nursing Studies* 52, no. 6: 1097-1106. https://doi.org/10.1016/j.ijnurstu.2015.02.001.

Soubra, R., A. Chkeir, and J.-L. Novella. 2019. "A Systematic Review of Thirty-One Assessment Tests to Evaluate Mobility in Older Adults." *BioMed Research International* 2019: 1354362. https://doi.org/10.1155/2019/1354362.

Sterling, P., and J. Eyer. 1988. *Allostasis: A New Paradigm to Explain Arousal Pathology*. NJ, USA: Handbook of Life Stress, Cognition and Health.

Stern, Y. 2009. "Cognitive reserve." *Neuropsychologia* 47, no. 10: 2015-2028. https://doi.org/10.1016/j.neuropsychologia.2009.03.004.

van Druten, V. P., E. A. Bartels, D. van de Mheen, E. de Vries, A. P. M. Kerckhoffs, and L. M. W. Nahar-van Venrooij. 2022. "Concepts of Health in Different Contexts: A Scoping Review." *BMC Health Services Research* 22, no. 1: 389. https://doi.org/10.1186/s12913-022-07702-2.

Ware, J. E. 2000. "SF-36 Health Survey Update." *Spine* 25, no. 24: 3130-3139. https://doi.org/10.1097/00007632-200012150-00008.

Wing, J. K., T. Babor, T. Brugha, et al. 1990. "SCAN. Schedules for Clinical Assessment in Neuropsychiatry." *Archives of General Psychiatry* 47, no. 6: 589-593. https://doi.org/10.1001/archpsyc.1990.01810180089012.

World Health Organization. 1946. *Constitution of the World Health Organization*. New York, USA: World Health Organization. https://www.who.int/fr/about-us/who-we-are/constitution.

World Health Organization. 1986. *The Ottawa Charter for Health Promotion*. Ottawa, Canada: World Health Organization. http://www.who.int/healthpromotion/conferences/previous/ottawa/en/.