Theodore D. Cosco , MSc 1 , Joshua J. Armstrong , PhD 2 , Blossom C.M. Stephan , PhD 3 , Carol Brayne , MD 1
1 Cambridge Institute of Public Health, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK;
2 Geriatric Medicine Research, Division of Geriatric Medicine, Dalhousie University, Halifax, Canada;
3 Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UKDOI: http://dx.doi.org/10.5770/cgj.18.131
The conceptualization of positive and negative states of aging is contentious at the inter- and intraparadigm level; lack of consensus exists within and between states. Working within their respective paradigms, successful aging and frailty researchers may have lost sight of the larger picture. Are successful aging researchers describing nonfrail individuals? Are frailty researchers describing unsuccessful aging? It is imperative that researchers are cognizant of the ways in which their perspectives are contextualized within the literature and within related paradigms, so as to be able to clearly communicate their research and to ensure they are working within the appropriate paradigm to facilitate desired outcomes. Here we discuss the similarities and differences between successful aging and frailty in terms of the scope and emphasis of their constituent components and functioning: both SA and frailty include biomedical components; SA examines the high end, whilst frailty predominately examines the low end of the functioning spectrum. Frailty models emphasize the biomedical realm, whilst SA models emphasize both the biomedical and the psychosocial.
Key words: successful aging , frailty , conceptualization , models of aging
The conceptualization of positive and negative states of aging is contentious at the inter- and intraparadigm level; lack of consensus exists within and between states. Further, the language used to articulate these states often belies fundamental conceptual commonalities;(1) within the remit of specific paradigms, researchers may be describing similar phenomena, but framing them in disparate ways. The pursuit of aging well—or successful aging (SA)—has increased dramatically, with the number of different SA conceptualizations increasing proportionally.(2,3) In addition to conceptual issues within the SA paradigm are issues concerning how SA and frailty paradigms coexist conceptually and are articulated in the literature. Working within their respective paradigms, researchers may have lost sight of the larger picture. Are SA researchers describing nonfrail individuals? Are frailty researchers describing unsuccessful aging?
SA is focused on positive states, whilst acknowledging the heterogeneity of aging trajectories and variation in key dimensions affected by aging.(4) There have been more than 100 operational definitions of SA posited, ranging from strictly biomedical models (i.e., including only physical and cognitive functioning) to single-item, self-reported measures of SA.(2) These models are largely based on the popular Rowe & Kahn model of SA: low probability of illness, physical/cognitive functioning, and engagement.(4) SA models are increasingly multidimensional;(5) a recent systematic review of lay perspectives demonstrates the importance of psychosocial components(3) in definitions of SA.
At a basic level, frailty is concerned with increased vulnerability that develops as a consequence of age-related decline;(6) however, similar to SA, no consensus definition has emerged.(7) A systematic review of frailty outcome instruments identified eight frailty domains: nutritional status, physical activity, mobility, strength, energy, cognition, mood, and social relations/support. The most prolific frailty model, The Fried Frailty Phenotype,(8) includes weight loss, weakness, exhaustion, low activity level, and slow gait speed. Despite conceptual frameworks that advocate multidimensional models of frailty,(7) the most common components of frailty instruments are biomedical (e.g., mobility), and the least common are psychosocial (e.g., social relations/support).(6)
Both frailty and SA models include physiological aspects of aging. Frailty models primarily include biomedical measures of health(6) (e.g., activities of daily living)—as do many SA models(2)—working outside and across disease- and functionally specific domains. These models endeavor to capture a holistic level of functioning, providing a measure of the general state of the individual.
Whilst frailty models focus on health deficits, SA models focus on the fostering of strengths, with a greater emphasis on psychosocial components. For example, the frailty phenotype does not include psychosocial components amongst its five items,(8) whilst the Rowe & Kahn model includes engagement amongst its three items.(4) Although there are many shared biomedically focused components of both models (e.g., activities of daily living), the perspectives adopted by frailty and SA are inherently different.
Frailty is primarily concerned with the low end of the functioning continuum, whilst SA is primarily concerned with the high end. As a result of inhabiting opposite ends of a shared functioning continuum, it may be suggested that these concepts are polar opposites. With respect to biomedical aspects of functioning, this is a fair observation; however, SA has a stronger emphasis on psychosocial components than frailty models. Consequently, SA cannot be simplified to “the opposite of frailty”.
Both SA and frailty include biomedical components; SA examines the high end, whilst frailty predominately examines the low end of the functioning spectrum. Frailty models emphasize the biomedical realm, whilst SA models emphasize both the biomedical and the psychosocial. It is imperative that researchers are cognizant of the ways in which their perspectives are contextualized within the literature and within related paradigms, so as to be able to clearly communicate their research and to ensure they are working within the appropriate paradigm to facilitate desired outcomes. For example, studies examining terminal decline in end-stage renal disease patients may be better suited to examination in a frailty framework, whereas studies examining the well-being fostered in community participation schemes may be better suited to a SA framework. In the interest of collectively moving aging research forward, researchers must be cognizant of the theoretical framework in which they are working in order to best facilitate the intended outcomes of the study.
TDC and JJA would like to thank the Canadian Institutes of Health Research and the Centre for Ageing Research and Development in Ireland for providing the awards that enabled them to travel to Dublin for the International Training Program on Ageing where this paper was conceived.
The authors declare that no conflicts of interest exist.
1. Cosco TD, Stephan BC, Brayne C. On the success of the successful aging paradigm. J Appl Gerontol. 2013;32(3):275–76.
2. Cosco TD, Prina AM, Perales J, et al. Operational definitions of successful aging: a systematic review. Int Psychogeriatr. 2014;26(3):373–81.
3. Cosco TD, Prina AM, Perales J, et al. Lay perspectives of successful ageing: a systematic review and meta-ethnography. BMJ Open. 2013;3(6):002710.
4. Rowe JW, Kahn RL. Human aging: usual and successful. Science. 1987;237(10): 143–149.
5. Cosco TD, Prina AM, Perales J, et al. Whose “successful ageing”? Lay- and researcher-driven conceptualisations of ageing well. Eur J Psychiat. 2014;28(2):124–30.
6. de Vries NM, Staal JB, van Ravensberg CD, et al. Outcome instruments to measure frailty: a systematic review. Ageing Resh Rev. 2011;10(1):104–14.
7. Gobbens RJ, Luijkx KG, Wijnen-Sponselee MT, et al. Towards an integral conceptual model of frailty. J Nutrition Health Aging. 2010;14(3):175–81.
8. Fried LP, Tangen CM, Walston J, et al. Frailty in older adults: evidence for a phenotype. J Gerontol Series A, Biol Sci Med Sci. 2001;56(3):M146–M156.
Canadian Geriatrics Journal , Vol. 18 , No. 1 , March 2015