jfa journal

AND option

OR option


A. Zamudio-Rodríguez1, J.-F. Dartigues1, H. Amieva1, K. Pérès1

1. University of Bordeaux, Inserm, Bordeaux Population Health Research Center, UMR 1219, Bordeaux, France.
Corresponding author: Alfonso Zamudio Rodríguez. Centre de recherche Inserm, UMR 1219. Rue Léo Saignat, 33076 Bordeaux cedex, France. Phone: +33 (5) Fax: +33 (5), E-mail: alfonso.zamudio-rodriguez@u-bordeaux.fr

J Frailty Aging 2020;in press
Published online November 24, 2020, http://dx.doi.org/10.14283/jfa.2020.62


The population of older adults over 60 years is growing faster than any other age group and will more than double between 2020 and 2050. This increase has led to clinical, public health, and policy interest in how to age “successfully”. Before the Rowe and Kahn’s model proposed thirty years ago, aging was seen as a process of losses associated with diseases and disability. However, since the emergence of this model, there has been a shift towards a more positive view, serving for promoting diverse medical or psychosocial models, and personal perspectives. Several technical terms of “success” (e.g. “successful aging”, “healthy aging”, “active aging”, “aging well”…) coexist and compete for the meaning of the concept in the absence of a consensual definition. Our literature review article aims to study discrepancies and similarities between the main technical terms through quantitative or qualitative studies. A literature review using PubMed, SCOPUS, PsycINFO, Psycarticles, Psychology, and Behavioral Sciences Collection, Cochrane database, and clinicaltrials.gov databases was conducted. A total of 1057 articles were found and finally, 43 papers were selected for full extraction. We identified several components in these definitions, which reveal considerable inconsistency. The results particularly suggest that lay personals perspectives could bridge the gap between biomedical and psychosocial models in successful aging. In conclusion, an optimal definition would be a multidimensional one that could combine functional capacities, psychosocial abilities, environmental factors and subjective assessments of one’s own criteria to discriminate older adults at potential risk of “unsuccessful” aging to healthy aging trajectories.

Key words: Healthy aging, public health, review, successful aging, theorical models.



More people than ever before are reaching older ages. The proportion of people over 60 years is growing faster than any other age group due to both increasing longevity and declining fertility rates. Furthermore, in many industrialized countries, the first generations after the Second World War are currently reaching old age, the so-called baby boomers. The current aging population will more than double between 2020 and 2050, whereas the oldest old one –those aged over 80 years- should be multiplied by 5 in the same period (1). This demographic revolution has led to clinical, public health, policy, and individual interest regarding how to age “successfully”. The first key element in order to determine this “success” was established in 1948 when the World Health Organization (WHO) Member States adopted a new definition of health as “a state of complete physical, mental, and social well-being and not merely the absence of diseases” (2). However, despite this framework, the conception of aging was viewed as a period of degradation associated with disease and dependency, where little attention was given to people with healthy trajectories.
In 1961, the introduction of the term “Successful Aging” (SA) induced a fundamental shift, even though the consensus over the definition of this new concept and the way to measure it was (and to a certain extent still is) far from being reached (3). Actually, the word “successfully” is commonly used in the literature as a universal reference term for older people with healthy trajectories. Moreover, this concept brought a step that fostered the development of a positive view of aging and promoted research in order to demonstrate a possibly high level of functioning across several domains in old age. Consequently, different technical terms have emerged. These terms co-exist and compete to define this concept, including successful, healthy, active, well-being and others; terms that are often overlapping (4).
In 1987, Rowe and Kahn proposed in the normal category of aging, an additional distinction between usual and SA as nonpathological states. Eventually, ten years later, they summarized the central findings of that work, proposing the first model of “SA”, which was defined as “a low probability of disease and disability, high cognitive and physical functioning, as well as productive activity and activity involving relations with others” (5). This model has been essential in our understanding of the healthy aging process. Nonetheless, this model mainly relied on a biomedical approach underestimating the contribution of psychosocial, or personal perspectives on the aging process.
On the other hand, after Rowe and Kahn’s model of SA, numerous holistic theories have been proposed to improve the concept using different approaches involving environmental factors, security, and social active engagement models (6), until more recently ones based on subjective criteria, such as life-satisfaction or well-being (7, 8). These theories suggest a shift to a more holistic vision of SA (9, 10). In this vein, the WHO introduced in 2002 the concept of “active aging”, defined as: “Process of optimizing opportunities of health, participation, and security, seeking to improve life quality as people get older. Active aging consists of a health policy, influenced by gender and culture, and that is composed of behavioral, personal, physical, social, and economic determinants, as well as health and social service” (4).
Even though, more than half a century has passed since the introduction of the different technical terms of SA (“healthy”, “active”, “successful”, “well-being”, …), no universal operationalization or standardized definition has emerged (11). A variety of objective and subjective measures have been proposed in order to operationalize it (12) and several essential components have been identified, such as cognitive, physical, psychosocial, or environmental dimensions (13–15). Our literature review article aims to identify discrepancies and convergences between the main technical terms of SA through quantitative or qualitative or mixed methodology.



Search strategy

A literature review through PubMed, SCOPUS, PsycINFO, Psycarticles, Psychology and Behavioral Sciences Collection, Cochrane database, and clinicaltrials.gov databases was conducted. The comprehensive research strategy included six successful technical terms: “successful aging”, “healthy aging”, “active aging”, “aging well”, “self-perceived successful aging”, and “subjective well-being in late life”.
These terms were used in orthography conventions of both “aging” and “ageing”. In addition, where possible, some restrictions were used in the database such as “original articles” type of publication, “English” language, articles involving only “humans”, and the age of the participants “65 years and older” at the time of assessment of SA. This process was replicated where possible through the seven databases mentioned above by using the successful technical terms sequentially followed by the three keywords: “Definition” OR “concept” OR “determinant”. A wildcat operator, i.e. “*”, was inserted as a suffix to capture all permutations. The research included all the articles published before July 2019. A total of 1,057 articles were found, of which 650 were screened after deleting 407 duplicates.

Study inclusion

Peer-reviewed research articles on the SA concept, conducted through quantitative, qualitative, or mixed methodology in community-dwelling older adults, were included. When an author published several articles with the same techical term, the most relevant ones were taken into account according to the inclusion criteria. Included articles were then rated for relevance to our study objective.

Exclusion criteria

We excluded book reviews, short comments, letters, and papers which had a specialized focus solely on biology, physiology, immunology, genetics, laboratory or animal research, practical therapy, etc. Studies conducted in older adults with specific pathological conditions (e.g., HIV, frailty, cancer, Alzheimer’s disease) were excluded since the perspective of this review is the SA in the general older population.

Data extraction

The title (first) and abstract (second) of each article were reviewed in order to identify relevancy for full-text extraction. Forty-three articles were selected for full extraction (Figure 1).

Figure 1
Inclusion flowchart of the screening process for study inclusion

*Specific subject on biology, physiology, immunology, genetics, laboratory or animal research, practical therapy, odontology, nutrition, etc. †Specific pathological conditions e.g., HIV, frailty, cancer, Alzheimer’s disease.


Included studies

The global search strategy identified 1,057 articles. After exclusion of the duplicates, the screening on title (n=650) and abstract (n=218) finally led to 43 studies that met inclusion criteria for full-text extraction (Figure 1). We distinguished 19 quantitative, 23 qualitative and 1 mixed-method studies that are summarized in tables 1 and 2 displaying: Authors, year, country, age population, study design (cross-sectional/longitudinal), sample size, models, operational definition, and main results.

Study characteristics

As may be seen in tables 1 and 2, the majority of the studies (19 of the 43 studies) were conducted in the United States. The sample size ranged widely from 15 to 17,886 and the age of participants from 15 to 102 years. Nearly half of the studies used quantitative methods and half qualitative methods (one study used mixed). Interestingly, the two thirds were published in the last ten years.

Table 1
Operationalization of SA and the Outcome Measures of Quantitative Studies

OR= odds ratio; IC= confidence interval; Non-standardized coefficients; HR: hazard ratio; SA=Successful Aging, QoL= quality of life; RR= relative risk; MCI= mild cognitive impairment; Receiver operating characteristic= ROC; AUC = Area Under the ROC Curve

Table 2
The Conception of SA by Integrating Older People’s Views in Qualitative Studies


A healthy aging trajectory could be more than only “successfully”?

Our literature review highlighted three main approaches of successful aging: 1) The biomedical models “focusing largely in terms of absence of disease, frailty or dependence and the continued maintenance of the physical and cognitive functions” as the main elements; 2) The psychosocial perspectives which emphasize the quality of life, engagement in social activities, and personal or community support; 3) The laypersons’ perspectives models which refers to people’s conceptions regarding what it means to age well.

Models mainly biomedical

The biomedical models of SA are mainly based on “the optimization of life expectancy, taking into account high physical and mental functional performance, mobility, and high levels of independence” (16, 17).
In this sense, an approach combining both mortality and morbidity would be relevant to define SA, such as the Disability-Free Life Expectancy, the Disability-Adjusted Life Years (DALYs) (18) or the Disability-Adjusted Life Expectancy (DALE) (19) (Table 3). Those global measures of population health provide a useful assessment of the impact of premature death and disability and other non-fatal health outcomes in the short and long term, but these indicators are probably not subtle enough to cover all the dimensions of SA.
This multidimensionality is proposed in the Rowe and Kahn’s model which is a reference in the literature of SA. It relies on disease and disability, cognitive and physical functioning, and participation in social activities (5). Even though this model has been widely applied, it has several important limitations. First of all, on “normal” aging (non-pathological) the model distinguishes “usual” or “successful” aging, excluding aging people with diseases (pathological aging) from SA. Considering SA as disease-free is quite unrealistic and too restrictive. Indeed, as recently underlined by the WHO (20), above a certain age category, most of older persons have one or more diseases, which, when well controlled, have no or little influence on their wellbeing. This approach which only considers two non-pathologic groups of older people, i.e. “usual” or “successful”, does not reflect the considerable heterogeneity among older adults (21). The group called “usual” (non-pathologic but at high risk) involves people presenting a normal decrease in physical, cognitive, and social functioning concerning age whereas the group called “successful” (at low risk and high functioning) refers to high levels of physiological and cognitive functioning. Finally, this model does not take into account the self-perceived dimension of SA, making it primarily medical and objective (22) (Table 3).

Table 3
Multiple models of technical terms in Successful Aging with respect to operationalizations and outcomes

Note: LY= year prevalence; Q= disability weight; PYLL= years of life lost due to premature death; BWB: Physical well-being; RMSEA= Root mean square error of approximation. *=Weights closer to 1 imply that a year spent in that condition is perceived as being more equivalent to death than to a state of health; †=Percentage of Participants Aging. Successfully by Definition of Successful Aging and Individual Characteristics for; ‡= These five domains are each individually well documented in the research literature; §= Percentages are weighted; **= p<0.001 for age groups. 1= Northern: Denmark, Sweden, Estonia; 2= Western: Austria, Belgium, France, Germany, Luxembourg, Holland /The Netherlands, Switzerland; 3= Southern: Italy, Spain; 4= Eastern: Czech Republic, Slovenia


Towards a more holistic approach: the introduction of psychosocial and environment factors

The current view relies on an holistic conception of SA that encompasses physical and cognitive functioning (23, 24), autonomy (25), independence (26), environment factors (living environment) (27), financial security (28), social, family and couple relationships (29, 30).
In this context, an initiative emerged from the 21st-century aging research agenda developed by the United Nations and the International Association of Gerontology and Geriatrics in 2004, the Global Research Network on Ageing (GARNet) (31) (Table 3). GARNet is a collaborative project of “aging-well” which uses the GARNet index that measures the five following domains: physical health and dependency; mental/cognitive effectiveness; social support resources; daily life activity (engagement), and material security. This initiative promotes the adoption of aging-well strategies that enable health and well-being, which is essential for extending life span and quality of life. Aging-well, it relies on individual behaviors and life-course material and social environments that limit functional decline (mainly caused by chronic conditions) to help older adults maintaining their independence and health (31). In this sense, it progressively decenters the approach from pure health; well-being becoming the central goal of the model along with quality of life, which increases the scope for enjoying the additional years of life. Showing high levels of well-being in older adults should not be overlooked since it is becoming an increasingly important goal for older adults themselves, caregivers, and also physicians (15). In fact, it has been shown that up to 45-50% of older people express satisfaction with their aging process even though they are poorly performing on objective measures (6). This finding can be seen at first sight as a paradox since with advancing age, older adults experience higher levels of well-being, until about 3-5 years near the end of life (26). Well-being is an integral component of adding life to years in an increasing longevity context, emphasizing the need for a multidimensional definition of SA (32).
In 2014, the WHO’s term proposed in a policy framework such as Active and Healthy Aging (AHA), as “the process of optimizing opportunities for health, participation and security in order to enhance quality of life as people age” (33) which became widely accepted, but without general agreement on what its application really means. So, the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) provided the use of operational tools to serve this purpose (34) with a focus on the relationship between activity and health. Since then, the concept was enriched with the addition of “active” as an extension of the concept for “healthy aging” being still more holistic and inclusive, encompassing different domains (e.g. social, economic, cultural, spiritual and civic affairs) (35) (Table 3). The AHA aims to lengthen life expectancy and delay functional dependency, thus preserving autonomy. The AHA working definition lists several steps to achieve these goals: 1) a multilevel approach of the AHA is necessary in order to determine the different items that must be considered; 2) it is necessary to find the tools that allow achieving the multilevel definition; 3) tools should be used in a single questionnaire; and 4) psychometric measurement capacities should be evaluated. However, at the same time, the AHA definition raises fundamental concerns both on structural and economic barriers. In addition, active aging and SA focuses on “youthful” activities that emphasize health and independence in a very ambitious way, which could lead to a form of stigmatization, i.e. “youthism”, if this level of activity is not reached. On the other hand, the economic downturn in different parts of the world could lead to material difficulties and with the resulting loss of opportunities for activity.
More recently, in 2016, the World Health Assembly reframed the components of healthy aging as part of the global strategy and plan of action on aging and health. This framework views healthy aging from a functional rather than a disease-based perspective as “the process of developing and maintaining functional ability that leads to well-being in old age” (20). Functional ability is determined by the person’s intrinsic capacity (i.e. all the individual physical and mental capacities that a person can draw on in daily life), the relevant environmental factors (i.e., all the resources or barriers that will determine whether a person can engage him/herself in activities or not) and the interaction between the two. Functional ability is defined as the health-related attributes that enable people to be and do what they have reason to value (i.e., meeting basic needs; learning, growing and making decisions; moving around; building and maintaining relationships; and contributing). Using the International Classification of Functioning, Disability and Health (ICF) (36) framework as background in order to facilitate the translation of the current theoretical model into practice, it is important to identify the inner nature of its constituting constructs, in particular, the constituent elements of the central construct of intrinsic capacity (i.e. locomotion, vitality, cognition, psychological, vision or hearing) (Table 3).to know where to observe, what to measure and how to monitor. Consequently, healthy aging shows the continuous interaction between intrinsic capacity of individuals in link with the environments they inhabit (supportive or barrier): appropriate and integrated care (technical and medical products, artificial replacements, transplants…), technical aids (auxiliary device, such as a walking stick, wheelchair…), social resources on which the older person can rely on, the use of technologies or support for multiple services (accessible stores, banks and professional services) (20, 37). The health policy of the Global Strategy and Action in this area is generally in the framework of the notion of age-friendly environments, involving both physical and social components (20).

Laypersons’ perspectives

Qualitative research contributed to improving the conception of SA by integrating older people’s views (38) which have essential implications of what individuals consider as SA for complementing traditional models (39), which are predominantly studied by models based on quanlitative approach.
Lay perspectives include a broad framework of criteria that combine basic resources (Table 2 and 3) (functioning (23), social health (40), financial security (41), family and intergenerational care (42) psychological factors (mental) (29), personal attitudinal (43), life satisfaction (35), positive outlook (44), self-consciousness (45), behavioral strategies (resilience (42), coping (44), contribution to life (26), accomplishments (29), productivity (35), learning new things (46), adaptation to an aging body (28) and beliefs (spirituality (27), having a sense of purpose (47), cultural variations (9), among others.
On the one hand, studies suggest that lay perspectives in SA give a great value to the importance of the psychological aspects of older adults, as accepting oneself, including the development of a realistic self-appraisal and a review of one’s past experiences “I’ve never felt more authentically me, ever, than I do right now. And it’s just so cool…” (45). On the other hand, this approach also focuses on social environments of older adults, the importance of active engagement with life and growth, including novel, productive, and social engagement, and the value of a positive attitude: “Keep your old friends, make some new ones, don’t isolate yourself” (45, 48). As a result of these model, the concept of SA is explored across cultures experiences and values that the population can express, as individuals provided with a conscience, language, and will (what is capable of value).
To illustrate the complementarity of older people’s perspectives with other traditional approaches of SA. A Dutch research on octogenarians with qualitative interviews compared the meaning of SA between two approaches; one based on laypersons’ perspectives and the other on the bio-psychosocial approach (major disability, cognitive impairment, depression, and regular social activities). According to this latter definition, only 10% of the participants were categorized as SA, compared to 81% of the participants as SA rated by laypersons’ perspectives definition. As a conclusion of this study, older persons view SA as a process of adaptation (e.g., thanks to strategy of coping or resilience) and maintain high levels of well-being despite disease or disability (42). Rather than a state of sole physical or mental efficiency, where the presence of a disease in old age excludes from successful aging. SA should also integrate laypersons’ perspectives, as recently recommended by the WHO (20), where healthy aging is based on what people have reason to value and not the absence of disease. According to this approach, more persons could be considered to be successfully aged.
An essential resource for both personal and community development is the aspects of sustainability, which promote a more dynamic process of well-being in aging, such as financial security, which allows the use of resources such as health services, social activity, and civic participation (49).
However, despite its increasing importance in the literature, limited evidence has been provided to assess how the views of laypeople on SA brings added value to the concept of SA.



Our literature review aims to identify divergences and convergences from different technical terms of “successful aging” across quantitative and qualitative studies. This review confirms that since the initial coining of the term SA more than 50 years ago, the conceptualization and operationalization of the concept remains controversial and tricky to achieve. Many definitions of SA emerged and with them, multiple research methods, including unidimensional (14) or multidimensional (32) approaches, models based on objective or subjective (50)criteria, with qualitative or quantitative or mixed methodology, following a continuum (51) or through dichotomous profiles.
One of the lessons learned is the increasing importance given to the personal perspectives of the older persons. A recent review of operational definitions of SA reveals that there are more than twice as many studies that postulate operational definitions of SA as studies that examine lay perspectives of SA (52). As recommended in the Healthy Aging concept proposed by the WHO (20),the SA approach should be centered on what is important to the person and the ways (medical and environmental) to reach this goal. As they age, individual’s place a high value in the achievement of social goals, frequently related to family (partner, children and brothers/sisters) and leisure activities, or receiving emotional care (e.g. the care of the partner) (28, 43, 53, 54). In this sense, SA needs to be multi-dimensional and be seen as a continuum instead of dichotomized (successful versus unsuccessful) category, and needs to incorporate layperson’s perspectives for social significance, to be sensitive to differences in opportunities to age successfully and to variations in values between cultures (29, 55, 56).
This review also evidences the profound heterogeneity in the operationalization of the SA concept. The activity and social engagement elements (6) were identified as those reported most frequently. In addition, elements as economy and nature are absent in most conceptualizations of the SA. In this field, many authors addressed the topic of SA with their own outcome measures, assuming an adequate approach without much attempt at conceptual or theoretical definition. The SA models vary from pure biomedical (57, 58) (solely based on physical and cognitive parameters -e.g., studies on healthy life expectancy-) (59), to pure psychosocial (holistic conception –e.g., age-friendly environments-) or the lay models (older people’s views), while, some others, postulate intrinsic interactions among the different dimensions, which evidence the complexity of the term “successfully” in the aging process. Finally, another issue results from the fact that some parameters are used to define SA in some studies, whereas in others they are considered as outcomes. For instance, life satisfaction is assumed to be an essential predictor of SA while it is also defined as a significant outcome of SA (35).
This review has limitations. First, it was not possible to classify studies by technical term, due to the wide overlapping of the approaches used and the lack of clarity regarding the theoretical definitions, as mentioned above. We also limited our research after 65 years of age and only focused on the most frequently used models of the literature (limiting our research on six successful technical terms).
The main strength of our review is that it included both quantitative and qualitative studies. Considering such a range of studies allowed highlighting significant divergences between biomedical conceptualizations of SA and layperson’s perspectives approaches.



Healthy aging is an interrelated multidimensional process profoundly heterogeneous, with significant variations between individuals in the experiences lived. For healthy aging trajectories, an optimal approach should be one’s in terms of functional capacity, psychosocial abilities, environmental factors across the life course and also subjective assessments of one’s own criteria. This operationalized definition is crucial to provide pragmatic tools able to identify older adults with potential risk of “unsuccessful” aging and also ways to improve healthy aging trajectories of individuals. Therefore, the need for a consensual and operational definition is becoming a necessity not to say an emergency to face the public health, social, economic and individual challenges induced by our fast-aging populations.


Acknowledgments: The authors thank Coralie Thore for providing assistance with documentary support. AZR in appreciation of Mr. Pierre and Mrs. Aline Costet for your splendid hospitality during the summer of 2020.
Author Contributions: AZR and KP planned the review and search protocol; AZR wrote the paper review and conducted the data extraction. KP contributed to draft revisions. JFD and HA reviewed this paper.
Funding: The Fondation pour la Recherche Médicale (DOC20161136217 to AZR) supported this work. Funding has no role in the design, analysis, or preparation of this manuscript.
Ethical approval: Not required.
Data sharing statement: No additional data are available.



1. United Nations. Department of Economic and Social Affairs, Population Division. World Population Ageing. 2019. www.unpopulation.org. Accessed 26 May 2020
2. World Health Organization. Basic documents: forty-ninth edition (including amendments adopted up to 31 May 2019). 2020. http://apps.who.int/iris. Accessed 05 June 2020.
3. Havighurst RJ. Successful Aging1. The Gerontologist 1961;1:8–13
4. Bélanger E, Ahmed T, Filiatrault J, Yu H-T, Zunzunegui MV. An Empirical Comparison of Different Models of Active Aging in Canada: The International Mobility in Aging Study. Gerontologist 2015;57:197–205
5. Rowe JW, Kahn RL. Human aging: usual and successful. Science 1987;237:143–149
6. Doyle YG, Mc Kee M, Sherriff M. A model of successful ageing in British populations. The European Journal of Public Health 2012;22:71–76
7. Iwamasa GY, Iwasaki M. A New Multidimensional Model of Successful Aging: Perceptions of Japanese American Older Adults. J Cross Cult Gerontol 2011;26:261–278
8. Stenner P, McFarquhar T, Bowling A. Older people and ‘active ageing’: Subjective aspects of ageing actively. J Health Psychol 2011;16:467–477
9. Tam M. Understanding and Theorizing the Role of Culture in the Conceptualizations of Successful Aging and Lifelong Learning. Educational Gerontology 2014;40:881–893
10. Fisher BJ. Successful aging and life satisfaction: A pilot study for conceptual clarification. Journal of Aging Studies 1992;6:191–202
11. Cosco TD, Prina AM, Perales J, Stephan BCM, Brayne C. Operational definitions of successful aging: a systematic review. Int Psychogeriatr 2014;26:373–381
12. Pruchno RA, Wilson-Genderson M, Cartwright F. A Two-Factor Model of Successful Aging. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences 2010;65B:671–679
13. Jeon S-N, Shin H, Lee H-J. Dynamics of Constructs in Successful Aging of Korean Elderly: Modified Rowe and Kahn’s Model. Osong Public Health and Research Perspectives 2012;3:137–144
14. Caballero FF, Soulis G, Engchuan W, et al. Advanced analytical methodologies for measuring healthy ageing and its determinants, using factor analysis and machine learning techniques: the ATHLOS project. Sci Rep 2017;7:43955
15. Ng TP, Broekman BFP, Niti M, Gwee X, Kua EH. Determinants of Successful Aging Using a Multidimensional Definition Among Chinese Elderly in Singapore. Am J Geriatr Psychiatry 2009;17:407–416
16. Palmore E. Predictors of successful aging. Gerontologist 1979;19:427–431
17. Strawbridge WJ, Wallhagen MI, Cohen RD. Successful Aging and Well-Being. Gerontologist 2002;42:727–733
18. Grosse SD, Lollar DJ, Campbell VA, Chamie M. Disability and Disability-Adjusted Life Years: Not the Same. Public Health Rep 2009;124:197–202
19. Mathers CD, Sadana R, Salomon JA, Murray CJ, Lopez AD. Estimates of DALE for 191 countries: methods and results. Lancet 2001;357:1685–91
20. World Health Organization (ed). World report on ageing and health. 2015. WHO, Geneva
21. Cosco TD, Stephan BCM, Brayne C. (Unsuccessful) Binary Modeling of Successful Aging in the Oldest-Old Adults: A Call for Continuum-Based Measures. J Am Geriatr Soc 2014;62:1597–1598
22. Rodriguez-Laso A, McLaughlin SJ, Urdaneta E, Yanguas J. Defining and Estimating Healthy Aging in Spain: A Cross-sectional Study. The Gerontologist 2018;58:388–398
23. Jopp DS, Wozniak D, Damarin AK, De Feo M, Jung S, Jeswani S. How Could Lay Perspectives on Successful Aging Complement Scientific Theory? Findings From a U.S. and a German Life-Span Sample. The Gerontologist 2015;55:91–106
24. Young Y, Fan M-Y, Parrish JM, Frick KD. Validation of a Novel Successful Aging Construct. Journal of the American Medical Directors Association 2009;10:314–322
25. Stenner P, McFarquhar T, Bowling A. Older people and ‘active ageing’: Subjective aspects of ageing actively. J Health Psychol 2011;16:467–477
26. Nosraty L, Jylhä M, Raittila T, Lumme-Sandt K. Perceptions by the oldest old of successful aging, Vitality 90+ Study. Journal of Aging Studies 2015;32:50–58
27. Tohit N, Browning CJ, Radermacher H. ‘We want a peaceful life here and hereafter’: healthy ageing perspectives of older Malays in Malaysia. Ageing and Society 2012;32:405–424
28. Amin I. Perceptions of Successful Aging among Older Adults in Bangladesh: An Exploratory Study. J Cross Cult Gerontol 2017;32:191–207
29. Nguyen AL, Seal DW. Cross-Cultural Comparison of Successful Aging Definitions Between Chinese and Hmong Elders in the United States. J Cross Cult Gerontol 2014;29:153–171
30. Lee JE, Kahana B, Kahana E. Successful Aging from the Viewpoint of Older Adults: Development of a Brief Successful Aging Inventory (SAI). Gerontology 2017;63:359–371
31. Hawkins BA. Aging Well: Toward a Way of Life for All People. Prev Chronic Dis 2005;2
32. Phelan EA, Anderson LA, Lacroix AZ, Larson EB. Older Adults’ Views of “Successful Aging”–How Do They Compare With Researchers’ Definitions? J Am Geriatr Soc 2004;52:211–216
33. World Health Organization. Active ageing: a policy framework. 2002. WHO, Geneva.
34. Bousquet J, Kuh D, Bewick M, et al. Operational definition of Active and Healthy Ageing (AHA): A conceptual framework. J Nutr Health Aging 2015;19:955–960
35. Marsillas S, De Donder L, Kardol T, et al. Does active ageing contribute to life satisfaction for older people? Testing a new model of active ageing. Eur J Ageing 2017;14:295–310
36. World Health Organization (ed). International classification of functioning, disability, and health: ICF short version. 2001. World Health Organization, Geneva
37. Schulz R, Heckhausen J. A life span model of successful aging. American Psychologist 1996;51:702–714
38. Tohit N, Browning CJ, Radermacher H. ‘We want a peaceful life here and hereafter’: healthy ageing perspectives of older Malays in Malaysia. Ageing & Society 2012;32:405–424
39. Jopp DS, Wozniak D, Damarin AK, De Feo M, Jung S, Jeswani S. How could lay perspectives on successful aging complement scientific theory? Findings from a u.s. And a German life-span sample. Gerontologist 2015;55:91–106
40. Bowling A. Enhancing later life: How older people perceive active ageing? Aging & Mental Health 2008;12:293–301
42. Montross LP, Depp C, Daly J, et al. Correlates of Self-Rated Successful Aging Among Community-Dwelling Older Adults. Am J Geriatr Psychiatry 2006;14:43–51
43. Bryant LL, Corbett KK, Kutner JS. In their own words: a model of healthy aging. Social Science & Medicine 2001;53:927–941
44. Fisher BJ. Successful aging and life satisfaction: A pilot study for conceptual clarification. Journal of Aging Studies 1992;6:191–202
45. Reichstadt J, Sengupta G, Depp CA, Palinkas LA, Jeste DV. Older Adults’ Perspectives on Successful Aging: Qualitative Interviews. Am J Geriatr Psychiatry 2010;18:567–575
46. Chen L-K. Benefits and dynamics of learning gained through volunteering: A qualitative exploration guided by seniors’ self-defined successful aging. Educational Gerontology 2016;42:220–230
47. Bowling A, Iliffe S. Which model of successful ageing should be used? Baseline findings from a British longitudinal survey of ageing. Age and Ageing 2006;35:607–614
48. Douglas H, Georgiou A, Westbrook J. Social participation as an indicator of successful aging: an overview of concepts and their associations with health. Aust Health Review 2017;41:455
49. Chong AM-L, Ng S-H, Woo J, Kwan AY-H. Positive ageing: the views of middle-aged and older adults in Hong Kong. Ageing and Society 2006; 26:243–265
50. Cosco TD, Stephan BCM, Brayne C. Validation of an a priori, index model of successful aging in a population-based cohort study: the successful aging index. Int Psychogeriatr 2015;27:1971–1977
51. McLaughlin SJ, Jette AM, Connell CM. An Examination of Healthy Aging Across a Conceptual Continuum: Prevalence Estimates, Demographic Patterns, and Validity. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2012;67:783–789
52. Cosco TD, Prina AM, Perales J, Stephan BCM, Brayne C. Lay perspectives of successful ageing: a systematic review and meta-ethnography. BMJ Open 2013;3:e002710
53. Hsu H-C. Exploring elderly people’s perspectives on successful ageing in Taiwan. Ageing and Society 2007;27:87–102
54. Lewis J. The Role of the Social Engagement in the Definition of Successful Ageing among Alaska Native Elders in Bristol Bay, Alaska. Psychology & Developing Societies 2014;26:263–290
55. Tam M. Understanding and Theorizing the Role of Culture in the Conceptualizations of Successful Aging and Lifelong Learning. Educational Gerontology 2014;40:881–893
56. Ng SH, Cheung C-K, Chong AML, Woo J, Kwan AYH, Lai S. Aging Well Socially through Engagement with Life: Adapting Rowe and Kahn’s Model of Successful Aging to Chinese Cultural Context. Int J Aging Hum Dev 2011; 73:313–330
57. Seeman TE, McEwen BS, Rowe JW, Singer BH. Allostatic load as a marker of cumulative biological risk: MacArthur studies of successful aging. Proceedings of the National Academy of Sciences 2001;98:4770–4775
58. Tyas SL, Snowdon DA, Desrosiers MF, Riley KP, Markesbery WR. Healthy ageing in the Nun Study: definition and neuropathologic correlates. Age Ageing 2007;36:650–655
59. Negash S, Smith GE, Pankratz S, et al. Successful Aging: Definitions and Prediction of Longevity and Conversion to Mild Cognitive Impairment. Am J Geriatr Psychiatry 2011;19:581–588
60. Ferdows NB, Jensen GA, Tarraf W. Healthy Aging After Age 65: A Life-Span Health Production Function Approach. Res Aging 2018;40:480–507
61. Nimrod G, Ben-Shem I. Successful Aging as a Lifelong Process. Educational Gerontology 2015;41:814–824





1. Center on Aging and Health, Johns Hopkins University, Baltimore, Maryland, USA; 2. Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore Maryland, USA; 3. Department of Philosophy, Loyola University of Maryland, Baltimore, Maryland, USA; 4. Division of Biostatistics and Bioinformatics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, USA
Corresponding author: Brian Buta, MHS, 2024 E. Monument St., Suite 2-700, Baltimore, Maryland. Phone: 410-502-3412. Email: bbuta@jhu.edu

J Frailty Aging 2018;7(2):127-133
Published online March 7, 2018, http://dx.doi.org/10.14283/jfa.2018.9



Introduction: Frailty affects 15% of non-institutionalized older adults in the United States, yet confusion remains in defining and, in turn, assessing frailty. Figurative language, such as metaphor, can help to explain difficult scientific concepts and to form new theories.  We aimed to examine the use of figurative language to describe frailty and to identify themes in the way figurative expressions are used. Understanding how frailty is described figuratively may offer insights for developing useful communication approaches in research settings. Methods: We performed a comprehensive review of editorials in the scientific literature to explore figurative language used to describe frailty in older adults. We categorized themes among the figurative expressions, which may help to inform how to effectively communicate about frailty. Results: We found 24 editorials containing 32 figurative expressions. The figurative expressions conceptualized frailty in six ways: 1) a complex, multifaceted concept; 2) an important issue in health and medicine; 3) indicative of something that is failing or faulty; 4) indicative of fragility; 5) representative of vulnerable, ignored persons; and 6) an opportunity for self-awareness and reflection. Discussion: Our review highlights the heterogeneity in depictions of frailty, which is consonant with the lack of a standardized definition of frailty. We also found a novel aspect to the concept of frailty, which merits attention: frailty characterized as an opportunity for self-awareness and reflection.  Figurative language, which often juxtaposes familiar with challenging, complex concepts, can offer insights on issues in frailty research and holds potential as a tool for researchers to improve communication about this important and debated medical condition.

Key words: Frailty, review, health communication and language.



Frailty is a recognized public health problem that has been estimated to impact nearly one out of every six non-institutionalized older adults in the United States (1). Research over the past two decades has led to a refined conceptualization of frailty as a state of physiological dysregulation that can lead to catastrophic health declines for persons encountering a stressor event (2, 3). However, the lack of an accepted working definition of frailty has led to complications for the field, most notably an ongoing confusion about the meaning of the word ‘frailty’ when used in research and scientific writing. While sometimes specifically defined, frailty is also used as a general synonym for vulnerability, poor health, functional decline, or old age (4). Part of this lack of clarity is due to the choice of the word itself; the term “frailty” is vague and difficult to precisely pinpoint (4, 5). Even when defined, confusion persists as to whether frailty should be assessed as a unified, biologically-driven phenomena (i.e., frailty phenotype) versus a cumulative effect of aging-related signs and symptoms (i.e., deficit accumulation index) (6). Frailty holds significant potential for risk prediction and clinical-decision making (7), though more guidance is needed on how to best incorporate it, and which measure(s) to use, in clinical settings (8).
The communication of scientific and medical concepts, such as frailty, is an important component of the research process, as well as clinical practice (9, 10).  In scientific discourse, figurative language can serve as a communication tool for the purposes of pedagogy and critical explanation, and for theoretical and constructive conceptualization (11, 12). Figurative comparisons, such as metaphor, often use a familiar concept to help explain or theorize on a complex or lesser known concept.  Using these techniques can help to make abstract concepts tangible and describe novel hypotheses in familiar terms. For example, a metaphor of war has often been used when depicting the scientific enterprise to understand the complicated mechanisms of cancer and its potential cures —a “battle against cancer” in which the patient must fight an invasive enemy (13, 14). In another example, discoveries in genetics have led to changes in the use of figurative expressions over time: first, a “blueprint of life” to give an architectural tangibility to the human genome; and, later, “pianists” that “play” the static genetic information in DNA to describe epigenetic processes (15).  Figurative comparisons may sometimes oversimplify, be reductionist, or even misshape and inhibit a more accurate understanding of scientific phenomena (16-18); for example, there are limitations to the utility of the war metaphor in cancer, especially given that surviving cancer may depend on many factors outside of how hard a patient “fights” (13, 19). Yet, the ability for figurative language to provide a view of one concept through comparisons to another holds value: these expressions can “often transcend the merely descriptive to yield profoundly enlightening insights” (20). Figurative techniques may offer novel and unexpected comparisons, and can also allow for relatable descriptions free of scientific jargon. Through such insights, figurative language may help to improve understanding and communication about complex scientific concepts – here, frailty – and may resonate more readily in research and in clinical practice.
In the following review, we identified figurative language that has been used to describe frailty in editorials among the academic research literature. Figurative expressions are more often found in editorials than in standard investigational articles, due to the typically unstructured and opinion-based nature of the editorial (21). We aimed to categorize the purposes of these figurative expressions, and to consider whether the use of figurative language can help to highlight common themes and provide insight into the ways researchers conceptualize and communicate about frailty.



We performed a comprehensive literature review to examine if and how figurative language has been used in editorials to describe frailty in older adults. We limited our search to editorials for two reasons: 1) editorials are typically opinion-based and may contain language with more “literary flair” (22) (see also Segal (21)); and 2) feasibility in terms of search size.  Our search was conducted from the start of the following databases through December 31, 2016: PubMed; EMBASE/MEDLINE; and CINAHL Plus/CINAHL/MEDLINE/PsycINFO combined. Please see the supplementary file (Appendix 1) for the specific search terms used in each database.
Citation files from each database were combined in EndNote X7, where de-duplication was performed. The first author (BB) reviewed the titles/abstracts of these articles and removed articles that did not focus on frailty. The full texts of the remaining articles were reviewed by two authors (BB, RM) to identify examples of figurative language, such as metaphor, simile, analogy, and other figurative techniques (23). See supplemental file, Appendix 2, for definitions.
Once identified, we analyzed the content to determine the purposes of the figurative language used, and classified expressions into categories that were generated inductively from this review. These categories, their definitions, and examples are described in the results section.



Our search identified 703 unique editorials (see Figure 1). After cursory review of titles and abstracts, 427 records were excluded for non-relevance. The remaining editorials were retrieved to review for the use of figurative language to describe frailty; 37 articles were further excluded for being unavailable or only in a non-English language. Of the reviewed 239 editorials, we found 24 editorials that included figurative language used to describe frailty. Table 1 summarizes these editorials, which were published between 1983 and 2016.


Figure 1 Systematic literature search for editorials on frailty

Figure 1
Systematic literature search for editorials on frailty


We identified 32 examples of figurative language used to describe frailty in these 24 articles. The most common figurative technique was metaphor, followed by analogy, simile, allusion, and allegory (see Appendix 2). After identifying figurative depictions of frailty, the purposes of the language used were classified into the following six categories:
(1)    Frailty as a complex, multifaceted concept: figurative language used to describe the complicated, intricate, sometimes evasive, nature of frailty, its etiology, ascertainment, and/or treatment;
(2)    Frailty as an important issue in health and medicine: figurative language used to highlight the significance of frailty identification or treatment;
(3)    Frailty as indicating something that is failing or faulty: figurative language used to compare a frail person to a broken or decaying object or process;
(4)    Frailty as indicating fragility: figurative language used to compare a frail person to a fragile or delicate object, which can be easily broken;
(5)    Frailty as representative of vulnerable but ignored persons: figurative language used to equate frail persons with images of neglect.
(6)    Frailty as an opportunity for self-awareness and reflection: figurative language used to describe the potential of the (physically) frail state to facilitate a greater attention to non-physical, spiritual, or self-reflections.

See Table 1 for information on the identified articles and figurative expressions, organized by category. Out of six categories, figurative language was most commonly utilized to discuss frailty as a complex, multifaceted concept.  The complicated nature of understanding, measuring, and treating frailty was presented with comparisons to hard-to-define concepts such as beauty (24), and emergent, hard-to-predict phenomena such as the weather (25). In terms of taking a measurement of frailty, necessarily a dynamically changing process, a figurative comparison was made to the difficulty of predicting the future speed of a car based on its characteristics at a stoplight (26). The treatment of frailty was compared to: the use of complex military strategies (27); a metaphor that frailty treatment may never have a “one-size-fits-all” solution (28); and an allegory of the Greek myth of Eos to question whether or not extending life span will simply extend frailty (29, 30). Other expressions depicted frailty as something that we are only beginning to recognize but still need to understand fully; in these examples, frailty was compared to a “figure in the stone” that is being carved out (31), or the “underwater part of the iceberg of aging” (32). These examples of figurative language all represent attempts to illustrate frailty as a complex, hard-to-define state.

Table 1 Figurative language used to describe frailty, organized by six categorical purposes of use

Table 1
Figurative language used to describe frailty, organized by six categorical purposes of use


The importance of frailty was evident in metaphors that compared it to one of the “cornerstones of contemporary health care for older people” (33) and a “public health time bomb” (34). Both the importance of frailty and the elusiveness around it are well-summarized by comparing frailty to the “Holy Grail” (35, 36).
Regarding properties or characteristics of those who are frail, we found comparisons of frailty to a failing or faulty entity. A frail person was compared to a “rickety car running out of gas” (37). In another example, a frail body was described as “irrational, the transient…the testimony to finitude, imperfection, and eventual death” (38).
A fourth category of expressions depicted frail persons as fragile, comparing them to delicate objects or as caught in vulnerable scenarios. Surgery in frail patients was described as like “knocking a porcelain figure off a table” (39), and treating frail patients was compared to “balancing on a tightrope” (40).
Frail patients were also depicted as a vulnerable but overlooked population in the health care system. Expressions within this category included describing frail persons as a “footnote” (41), “missing from the medical radar” (42), a “‘lost tribe’” (43), and an “elephant in the operating room” that is under-recognized and under-treated (44).
Lastly, frailty was described as an opportunity for self-awareness and reflection, using comparisons to a “lens” and “mirror” (42). One example described frailty as one “color of existence” that is “especially strong”, suggesting it may impact or strengthen one’s sense of self (38). Another example characterized frailty as an important, even positive, part of the human experience – “a limit and a freedom… a beloved whose so-called imperfections are an essential part of the whole” (38).



To our knowledge, this is the first literature review of the uses of figurative language to describe frailty in older adults. We found 32 examples in two dozen editorials that used figurative techniques to depict frailty. We identified six categories in which figurative expressions have been used to describe frailty, and found the most frequent purpose was to describe frailty as a complex, multifaceted, and often elusive concept.
In our first category, frailty was figuratively compared to complex and evasive concepts, which may reflect, or even result from, a lack of operational agreement and the numerous definitions used in research and clinical practice (45). Figurative language about frailty was also used to discuss key conceptual issues, such as: a) whether frailty measures should be dynamic versus static (5) in the figurative example of predicting the future speed of resting car (26); and b) whether the underlying primary and secondary causes of frailty can be better understood (46) in the metaphor of the submerged ice below an iceberg’s tip (32). From examples in our categories related to faulty or fragile objects, figurative language has also depicted a conceptual distinction between frail persons as those who are already presenting with evident symptoms and health problems – the “rickety cars” – versus those who are fragile, delicate and vulnerable of being easily overcome by stressors – the “porcelain figures”. This type of debate has ensued for more than a decade (47).
We would argue that figurative depictions, such as an easily relatable metaphor, can be helpful to the field by using commonly-understood comparisons to elucidate and speculate on unresolved topics in frailty research. To begin, metaphoric language can highlight and clarify a known problem with a new and unexpected comparison. For example, it has been argued that frailty assessments that focus solely on the static characteristics of a patient may not provide the information needed to understand the risk for serious declines and adverse outcomes; this critique of static measures has not been widely addressed beyond acknowledgment that collecting dynamic measures is more challenging. By figuratively comparing this issue to the clear difficulty of estimating the probable speed of car at rest, the point becomes more salient and relatable, despite the challenges involved with dynamic measurements.
Additionally, figurative language can add an emotional context that may highlight the severity or importance of an issue. A striking example is the statement “our gerontological souls are still bleeding” in the editorial by Ferrucci and colleagues, a comment that the existing definitions of frailty feel incomplete (30). The description of frailty as a “public health time bomb” is another dramatic example (34).
Some figurative and metaphoric language can exacerbate ageist stereotypes and make it challenging to communicate about frailty, especially to patients. In response to this type of concern, the Journal of the American Geriatrics Society recently changed its author guidelines to curb the use of negative, even catastrophic, aging-related terms (such as the common metaphor of the silver “tsunami”), which have been determined to be damaging to perceptions of aging (48).  In our study, the metaphor of a “rickety car running out of gas” (37) to describe a person who is frail depicted undesirable, body-centric traits of deterioration. Also, certain metaphors seem to depict frailty as potentially insurmountable; the allusion to the Holy Grail, the iceberg metaphor, and the “public health time bomb” all describe frailty in fatalistic and overwhelming terms. Though many challenges remain, much progress has been made in understanding the etiology, measurement and treatment of frailty during the past two decades. A more apt metaphor, therefore, can be seen with the analogy to sculpting, which states that approaches toward studying underlying causes of frailty «will begin to make the figure in the stone visible» (31) and that through rigorous, often time-consuming scientific investigations, answers to presently daunting questions can be reached.
Our finding that frailty may be characterized as an opportunity for self-awareness and reflection is unique and differs from the conventional medical view of successful aging (e.g., without physical declines). Frail patients have expressed that issues of spirituality and meaningful activities are lacking in the existing definitions of frailty, and that the ability to maintain a sense of self in spite of losses can foster frail older adults’ well-being (49, 50). Aging and frailty have been proposed as providing an opportunity for the significant development of understanding and embrace of change, letting go, and loss (51, 52).  In the “spiritual model” of aging outlined by Leder, aging itself can awaken a time of profound meaning in the lives of older, frail adults: “the very losses of aging can be recontextualized as modes of liberation. They awaken us to what was insubstantial in our previous lives. They allow the time and focus to re-form the self” (51). In this regard, frailty need not always be associated with that which is fragile and/or broken: rather, individuals can be strengthened by meeting the challenges of a frail body. Our findings provide examples for language that could help communicate a more positive and holistic concept of frailty, such as frailty as “a lens, through which differences can be appreciated” (42). Given a lack of evidence regarding what older adults know or want to know about frailty, this may offer an interesting new model to discuss some of the more positive, reflective aspects of aging and frailty.
The word “frailty” has given rise to many connotations, as depicted by the variety of figurative language found in this review, and evinced by the numerous definitions of frailty in the literature (45). This conceptual confusion about frailty has likely contributed to the proliferation of definitions and assessment instruments, as well as a variety of figurative expressions. The multiplicity of definitions has arguably hampered progress in research and clinical translation, especially by creating uncertainty about how to optimally assess frailty, and by conflating findings when frailty is measured with different instruments without consideration of the differing components of each assessment method. Also troubling, the terms “frail” and “frailty” continue to be used in research as catch-all adjectives for decline or old age with no specific meaning provided (4). Therefore, the use of the term and the figurative language used to characterize “frailty” must be done with thoughtfulness and precision; otherwise, alternative terms to capture the notion of critical declines in age-related physical and cognitive functions may be warranted. The following passage reinforces this idea:
“A new metaphor dramatically shifts perceptions of aging… by comparing the process of aging to building momentum, researchers as communicators can open a new way to thinking and talking about aging—something counter to currently available cultural idioms such as “fighting” aging or the importance of “staying young.” An innovative test of how messaging can affect people’s implicit associations showed that this metaphor reduced ageist attitudes by a remarkable 30%.” (48).
This supports the need for being more thoughtful about how we use figurative language to describe frailty. There appears to be room for improvement based on some of the metaphors identified, e.g., “rickety cars”, “lost tribe”, or frailty as a “testimony to… eventual death”.
In reviewing figurative language used to describe frailty in editorials, we identified categories that represent issues facing frailty research. Figurative language allows one to “test” concepts by using real-world comparisons; and it offers communication pathways that can function across disciplines. Creative comparisons that elucidate key problems facing the field may provide insights into evolving areas of frailty research and potentially point toward solutions to the lingering questions of how to meaningfully communicate about frailty. Frailty characterized as an opportunity for self-awareness and reflection is one such novel model of communication that merits serious consideration.


Acknowledgments: We thank the members of the Johns Hopkins Frailty & Multisystem Dysregulation Working Group for ongoing intellectual stimulation on the topic of frailty; the leaders of the Older Americans Independence Center (Drs. Walston and Bandeen-Roche) for their support; and Qian-Li Xue, PhD, and Michael B. Tager, MFA, for reviewing an early version of this manuscript and providing helpful input on the frailty-related content, and on definitions and classifications of figurative language, respectively. We thank the reviewers for their insightful comments.
Funding: This work was supported by the National Institute on Aging [P30AG021334 to B.B., R.V.]; the National Center for Advancing Translational Sciences [KL2TR001077 to N.L.S.]; from the American Cancer Society [CCCDA-16-002-01 to N.L.S.]; and American Geriatrics Society’s Health in Aging Foundation [T. Franklin Williams Scholarship Award to N.L.S.].
Conflict of interest: None.
Supplementary materials: Online



1.    Bandeen-Roche, K., et al., Frailty in Older Adults: A Nationally Representative Profile in the United States. J Gerontol A Biol Sci Med Sci, 2015. 70(11): p. 1427-34.
2.    Fried, L.P., et al., Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci, 2001;56(3): p. M146-56.
3.    Morley, J.E., et al., Frailty consensus: a call to action. J Am Med Dir Assoc, 2013;14(6): p. 392-7.
4.    Hogan, D.B., C. MacKnight, and H. Bergman, Models, definitions, and criteria of frailty. Aging Clin Exp Res, 2003;15(3 Suppl): p. 1-29.
5.    Gillick, M., Pinning down frailty. J Gerontol A Biol Sci Med Sci, 2001;56(3): p. M134-5.
6.    Walston, J.D. and K. Bandeen-Roche, Frailty: a tale of two concepts. BMC Med, 2015;13: p. 185.
7.    Walston, J., et al., Integrating Frailty Research into the Medical Specialties-Report from a U13 Conference. J Am Geriatr Soc, 2017.
8.    Sourial, N., et al., Implementing frailty into clinical practice: a cautionary tale. J Gerontol A Biol Sci Med Sci, 2013;68(12): p. 1505-11.
9.    Garvey, W.D., Communication: The Essence of Science: Facilitating Information Exchange Among Librarians, Scientists, Engineers, and Students. 1979, Elmsford, New York: Pergamon Press Ltd. 332.
10.    Zolnierek, K.B. and M.R. Dimatteo, Physician communication and patient adherence to treatment: a meta-analysis. Med Care, 2009;47(8): p. 826-34.
11.    Robson, S.J., The use of metaphor in scientific writing, in English. 1985, Iowa State University: Retrospective Theses and Dissertations. p. 39.
12.    Knudsen, S., Scientific metaphors going public. Journal of Pragmatics, 2003;35(8): p. 1247-1263.
13.    Reisfield, G.M. and G.R. Wilson, Use of metaphor in the discourse on cancer. J Clin Oncol, 2004;22(19): p. 4024-7.
14.    Harrington, K.J., The use of metaphor in discourse about cancer: a review of the literature. Clin J Oncol Nurs, 2012;16(4): p. 408-12.
15.    Stelmach, A. and B. Nerlich, Metaphors in search of a target: the curious case of epigenetics. New Genet Soc, 2015;34(2): p. 196-218.
16.    Ball, P. A metaphor too far. Nature, 2011.  DOI: 10.1038/news.2011.115.
17.    Nelkin, D., Molecular metaphors: the gene in popular discourse. Nat Rev Genet, 2001;2(7): p. 555-9.
18.    Pauwels, E., Communication: Mind the metaphor. Nature, 2013;500(7464): p. 523-4.
19.    Sontag, S., Illness as metaphor. 1978, New York, NY: Farrar, Straus and Giroux 88.
20.    Veale, T. and Y. Hao, Comprehending and Generating Apt Metaphors: A Web-driven, Case-based Approach to Figurative Language. AAAI, 2007;p. 1471-1476.
21.    Segal, J.Z., Strategies of influence in medical authorship. Soc Sci Med, 1993;37(4): p. 521-30.
22.    Singh, A. and S. Singh, What is a good editorial? Mens Sana Monogr, 2006;4(1): p. 14-7.
23.    Baldick, C. The Oxford Dictionary of Literary Terms (4 ed.). 2015;September 18, 2017]; 4:[Available from: September 18, 2017.
24.    Rockwood, K. and R. Hubbard, Frailty and the geriatrician. Age Ageing, 2004;33(5): p. 429-30.
25.    Bortz, W., Understanding frailty. J Gerontol A Biol Sci Med Sci, 2010;65(3): p. 255-6; discussion 257.
26.    Subbe, C.P. and S. Jones, Predicting speed at traffic lights–the problem with static assessments of frailty. Age Ageing, 2015;44(2): p. 180-1.
27.    Rockwood, K., Geriatric medicine and counterinsurgency: what can we learn about combating frailty? J Am Geriatr Soc, 2014;62(10): p. 1979-80.
28.    Pagani, L., Appropriate antimicrobial therapy in the elderly: when half-size does not fit all frail patients. Clin Microbiol Infect, 2015;21(1): p. 1-2.
29.    de Grey, A.D., Combating the Tithonus error: what works? Rejuvenation Res, 2008;11(4): p. 713-5.
30.    Ferrucci, L., A. Mahallati, and E.M. Simonsick, Frailty and the foolishness of Eos. J Gerontol A Biol Sci Med Sci, 2006;61(3): p. 260-1.
31.    Fried, L.P., R. Varadhan, and V.A. Bohr, Opinion section on frailty. Mech Ageing Dev, 2008;129(11): p. 665.
32.    Vidal, E.I., Frailty in older adults: perspectives for research and practice in Public Health. Cad Saude Publica, 2014;30(6): p. 1133-5.
33.    Hayes, N., Importance of identifying frailty. Nursing Older People, 2016;28(2): p. 5.
34.    Lancet Diabetes Endocrinology, E., Sarcopenia: a fate worth challenging. Lancet Diabetes Endocrinol, 2014;2(3): p. 183.
35.    Conroy, S., Defining frailty–the Holy Grail of geriatric medicine. J Nutr Health Aging, 2009;13(4): p. 389.
36.    Hubbard, R.E. and O. Theou, Frailty: enhancing the known knowns. Age Ageing, 2012;41(5): p. 574-5.
37.    Dobbels, F., O. Mauthner, and K. Milisen, Frailty in left ventricular assist device destination therapy: putting a new motor in a rickety old car running out of gas? J Heart Lung Transplant, 2014;33(4): p. 347-9.
38.    Gadow, S., Frailty and strength: The dialectic in aging. Gerontologist, 1983;23(2): p. 144-147.
39.    Speir, A., Defining frailty: “I know it when I see it”. J Thorac Cardiovasc Surg, 2015; 149(3): p. 875-6.
40.    Ebersole, P.R., Taking care of the frail elder: a vital balance. Geriatr Nurs, 1998; 19(4): p. 176.
41.    Butler, R.N. and K. Hyer, Reimbursement reform for the frail elderly. J Am Geriatr Soc, 1989;37(11): p. 1097-8.
42.    Chochinov, H.M. and D. Stienstra, Vulnerability and palliative care. Palliat Support Care, 2012;10(1): p. 1-2.
43.    Crotty, M. and J. Ratcliffe, If Mohammed won’t come to the mountain, the mountain must go to Mohammed. Age Ageing, 2011;40(3): p. 290-2.
44.    Richardson, K. and J. Hopker, One minute to assess frailty, but what should we do next? Anaesthesia, 2016;71(6): p. 622-626.
45.    Buta, B.J., et al., Frailty assessment instruments: Systematic characterization of the uses and contexts of highly-cited instruments. Ageing Res Rev, 2016;26: p. 53-61.
46.    Bergman, H., et al., Frailty: an emerging research and clinical paradigm–issues and controversies. J Gerontol A Biol Sci Med Sci, 2007;62(7): p. 731-7.
47.    Fried, L.P., et al., Untangling the concepts of disability, frailty, and comorbidity: implications for improved targeting and care. J Gerontol A Biol Sci Med Sci, 2004;59(3): p. 255-63.
48.    Lundebjerg, N.E., et al., When It Comes to Older Adults, Language Matters: Journal of the American Geriatrics Society Adopts Modified American Medical Association Style. J Am Geriatr Soc, 2017;65(7): p. 1386-1388.
49.    Andreasen, J., et al., Content validation of the Tilburg Frailty Indicator from the perspective of frail elderly. A qualitative explorative study. Arch Gerontol Geriatr, 2015;61(3): p. 392-9.
50.    Taube, E., et al., Being in a Bubble: the experience of loneliness among frail older people. J Adv Nurs, 2016;72(3): p. 631-40.
51.    Leder, D., Spiritual Community In Later Life: A modest proposal. Journal of Aging Studies, 1996;10(2): p. 103-116.
52.    Leder, D., Spiritual Passages: Embracing Life’s Sacred Journey. Inner Work Book. 1997, New York: Tarcher. 296.