1Norene Kelly, 1Peter Martin, 2Leonard W. Poon, et al.
This paper is designed as a stand-alone review with the expressed goal of supplementing the initial “definition” paper (Martin et al.) by performing a literature search on historically key discussions on successful aging. The paper systematically decomposes the key concepts to provide bases for discussion of new directions and next steps of research.
The term and concept of “successful aging” has been around for quite a long time and has gained enough momentum to have merited not just hundreds of articles but also a review of the larger quantitative studies (Depp & Jeste, 2006). Additionally, definitions of successful aging are plentiful enough to have been categorized among seven major elements, as put forth by eleven research teams (Phelan & Larson, 2002). Choosing items for a bibliography, then, is not a simple matter. Just as defining “successful aging” requires a value judgment (for we must decide what is desirable), compiling a bibliography demands similar decisions. Since numerous studies have endeavored to define, measure, and evaluate successful aging, we chose to focus on future directions, as suggested by six germane articles. Were the suggestions addressed and perhaps resolved by consequent research? What questions remain?
This paper first describes the methodology we developed to explore these questions, which resulted in six categories: 1) measures and operational definitions; 2) personality;
3) promotion and prevention; 4) subjective/objective criteria; 5) self-rating; and 6) synthesizing biomedical and psychosocial. Next we describe the successful aging literature pertaining to each of these six categories. Finally, we discuss the implications of these results for the future of successful aging research.
First, we conducted a search for articles that offered salient suggestions for future directions in successful aging research. Second, from this search, we identified six key pieces of literature (four seminal articles and two review articles) (see Table 1). These articles are listed in chronological order, and the results section maintains that order. Third, we extracted key thematic passages from these articles from which to refine the search terms, and identified an appropriate search term or terms from each of these excerpts (see Table 1). Fourth, we conducted literature searches for these search terms using the Web of Science database. Thus, the six categories of results are enumerated below.
“successful aging” +
|Havighurst, R. J. (1961). Successful aging. The Gerontologist, 1, 8-13.||“In gerontology it will probably be useful to use several different measures of successful aging, always being explicit about their relations to operational definitions of successful aging. In this way we are likely to learn more than if we limit ourselves to one theory and one definition of successful aging, with its appropriate measure.” (p. 12)||“measures”“operational definitions”|
|Neugarten, B. (1972). Personality and the aging process. The Gerontologist, 12(1), 9-15.||Afford central importance to personality factors and to the continuities in personality, and in seeing people as active rather than passive.||“personality”|
|Rowe, J.W., & Kahn, R.L. (1987). Human aging: usual and successful. Science, 237(4811), 143-149.||Need for interdisciplinary studies of the factors that determine the trajectory of function with advancing age. Most gerontological research is about average tendencies within different age groups; neglects the substantial heterogeneity within such groups (this heterogeneity appears to increase with increasing age). Age itself is not a sufficient explanatory variable (due to heterogeneity). Habits shaped by psychosocial influences are important. “These recommendations have in common a thrust toward health promotion and disease prevention in the elderly. A revolutionary increase in life span has already occurred. A corresponding increase in health span, the maintenance of full function as nearly as possible to the end of life, should be the next gerontological goal.” (p. 149)||“health promotion” “disease prevention”|
|Baltes, P. B., & Baltes, M. M. (1990). Psychological perspectives on successful aging: the model of selective optimization with compensation. In P. B. Baltes & M. M. Baltes (Eds.), Successful aging: perspectives from the behavioral sciences (pp. 1-34). Cambridge: Cambridge University Press.||“In summary, an encompassing definition of successful aging requires a value-based, systemic, and ecological perspective. Both subjective and objective indicators need to be considered within a given cultural context with its particular contents and ecological demands. However, both the objective aspects of medical, psychological and social functioning and the subjective aspects of life quality and life meaning seem to form a Gordian knot that no one is prepared to untie at the present time. Our suggested solution is to use multiple subjective and objective criteria and to explicitly recognize individual and cultural variations.” (p. 7)||“subjective” “objective”|
|Phelan, E. A., & Larson, E. B. (2002). “Successful aging”—Where next? Journal of the American Geriatric Society, 50(7), 1306-1308.||“Future research in the area of successful aging should attempt to compare the definitions of successful aging of aging individuals themselves with those developed by the research community.” (p. 1307). A patient-centered definition is essential for future research.
|Glass, T.A. (2003). Assessing the success of successful aging. Annals of Internal Medicine, 139(5), 382-383.||The 2 distinct schools, psychosocial and biomedical, do not yet agree on a definition; “We badly need a synthesis of these two approaches.” “…we need to know considerably more about what older people value and how they define successful aging; we know next to nothing about these two subjects.” (p. 282)“If our concept of successful aging includes dignity, autonomy, social engagement, and the absence of suffering, we will be better positioned to configure our systems of care to address the needs of older populations.” (p. 382-383)||“psychosocial biomedical”“biopsychosocial”|
Robert Havighurst: Measures and Operational Definitions of Successful Aging
One of the first gerontologists to discuss successful aging was Robert Havighurst (1961). He noted that “In gerontology it will probably be useful to use several different measures of successful aging, always being explicit about their relations to operational definitions of successful aging. In this way we are likely to learn more than if we limit ourselves to one theory and one definition of successful aging, with its appropriate measure” (p. 12). Based on this suggestion, we conducted a search that produced 181 results in Web of Science. Nineteen articles were particularly responsive to the use of different measures and operational definitions within the psychosocial realm.
Recent literature demonstrates that researchers utilize a wide variety of measures. Hank (2011) started with baseline interviews from the Survey of Health, Ageing, and Retirement in Europe to develop measures for a variety of specific successful aging criteria. Lee, Lan, and Yen (2011), in seeking to validate a four-factor model, had participants complete a Taiwan Social Change Survey that measured four factors (physical, psychological, social support, leisure activity); the authors said this survey defined the successful aging process. Another 2011 study (Troutman, Nies, Bentley, & Year) piloted the Successful Aging Inventory (SAI). A convenience sample of Black older adults completed a demographic form, the SAI, Purpose in Life Test, Life Satisfaction Inventory-A, Mastery Scale, and Center for Epidemiologic Studies Depression Scale. The authors stated that the SAI appeared acceptable for measuring successful aging in Black older adults.
Yuchi, Ming-Yu, Parrish, and Frick (2009) previously put forth a multidimensional concept of successful aging that integrated physiological, psychological, and sociological domains of health. Their 2009 study appeared to confirm its validity, and the authors stated that further research and refinement among the general population was warranted. Another 2009 study (Ng, Broekman, Niti, Gwee, & Kua, 2009) similarly supported use of a measure that incorporated multiple dimensions. They concluded that “In contrast to findings based on more restricted biomedical definitions of successful aging, a multidimensional definition of successful aging identified more variables including demographic status, psychosocial support, spirituality, and nutrition as salient determinants” (p. 407).
Also questioning a purely biomedical measure were Young, Frick, and Phelan (2009). They presented a new definition and conceptual framework of successful aging, together with an operational definition (measurement) that allowed successful aging to coexist with diseases and functional limitations when compensatory psychological and/or social mechanisms were used.
Other researchers have focused on a single dimension that contributes to successful aging. Resnick and Inguito (2011) suggested that the Resilience Scale can help identify older adults who are low in resilience, thus allowing for interventions to facilitate successful aging. In this case, the authors imply that resilience is one measure of successful aging. Connectedness was another measure used for successful aging. Register, Herman, and Tavakoli (2011) sought to develop and test a connectedness scale for older adults to, as they put it, advance the science of successful aging. Subthreshhold depression is another measure that has been linked to successful aging. Vahia et al. (2010) found that it may affect the longitudinal course of successful aging for large numbers of persons. Driscoll et al. (2008) looked at sleep quality and daytime alertness in late life as possible important “aspects” of successful aging. Cognitive functioning has also been identified as a central “component” of successful aging (Moore et al., 2007), while Fernandez-Ballesteros, Zamarron, Rudinger, and Schroots (2004) examined the role of competence in successful aging. Additionally, Ford et al. (2000) called “a sustained personal autonomy” a measure of successful aging.
Strawbridge, Cohen, Shema, and Kaplan (1996) analyzed six-year predictors of successful aging, using the measures of needing no assistance nor having difficulty on any of 13 activity/mobility measures, plus little or no difficulty on five physical performance measures. The authors stated that “Cross-sectional comparisons at follow-up revealed significantly higher community involvement, physical activity, and mental health for those aging successfully” (p. 135).
Although the MacArthur Studies of Successful Aging (Berkman et al., 1993) and many others measured successful aging by operationalizing Rowe and Kahn’s criteria, that approach has come under criticism for lack of a subjective component. Cernin, Lysack, and Lichtenberg (2011) used both objective MacArthur criteria and self-rated health criteria in their study of urban African American older adults. Since objective successful aging was related to quantity and quality of education and self-rated successful aging was related to a wider variety of variables, the authors concluded that objective factors alone may limit our understanding. A study of elderly Canadian men (Tate, Lah, & Cuddy, 2003) focused on the subjective, asking respondents to define “successful aging.” Strawbridge, Wallhagen, and Cohen (2002) noted that “understanding criteria used by older persons to assess their own successful aging should enhance the conceptualization and measurement of this elusive concept” (p. 727). Such an approach fits with the suggestions of Baltes and Baltes (1990) and Jeste, Depp, and Vahia (2010) (see Table 1).
Related to the subjective-objective issue is the consideration of cultural differences in such measures. In their examination of Thai elders, Ingersoll-Dayton, Saengtiencha, Kespichayawattana, and Aungsuroch (2004) asserted that psychological well-being may be conceptualized quite differently across cultures. Their research provided evidence for cultural variability in the nature of psychological well-being and the importance of developing culturally-relevant measures.
Finally, survival is rarely mentioned as a measurement of successful aging, yet has obvious relevancy. Nusselder and Peeters (2006) raised the issue of measuring not just functioning but also survival: “It is recommended that research on successful aging should be based on summary measures of population health that reflect both survival and functioning throughout life” (p. 448).
Bernice Neugarten: Personality Factors of Successful Aging
Neugarten (1972) suggested affording central importance to personality factors and to the continuities in personality when addressing the concept of successful aging. The search terms “successful aging” and “personality” produced 34 results in Web of Science. Personality was a prime topic in 15 of the articles.
The earliest literature in this search dates to 1992, in which Brandstadter and Greve developed a model to provide an explanatory account for the resilience of the self in old age. Stating that developmental changes and losses in later life impose a strain on personal continuity and identity, they examined the adaptive and protective mechanisms of the self in their study of successful aging. In 1993, Costa, Metter, and McCrae were similarly interested in the stability of personality, suggesting that a dependable basis for adaptation leads to successful aging. They reviewed evidence from longitudinal studies that showed that personality dispositions are stable after approximately age 30; as determinants of psychological well-being, such dispositions contribute to a sense of identity and allow an individual to plan for the future.
A study of personality, longevity, and successful aging among Tokyo metropolitan centenarians examined whether personality characteristics associated with longevity could also be related to successful aging, as measured by the Rosenberg Self-Esteem Scale and Cattell’s Anxiety Scale (Shimonaka, Nakazato, & Homma, 1996). They found that Type B behavior was associated with longevity; however, its relationship to successful aging differed between men and women.
Baltes and Lang (1997) examined differential aging via two distinct resource factors: a Sensorimotor-Cognitive factor and a Social-Personality factor. They found more and larger negative age effects in the resource-poorest group than in the resource-richest group, and used the metamodel of selective optimization with compensation (SOC) to interpret the findings. A more recent study by Weiland, Dammermann, & Stoppe (2011) examined how SOC competencies and depressive symptoms might be related, in particular examining the trait effects of SOC competencies. The authors found that the SOC ability is dynamic and mood dependent; “otherwise, there is no hint of life-long reduced SOC competencies or a trait effect which would be associated with an increased vulnerability to the development of a depressive disorder” (p. 114).
Eizenman, Nesselroade, Featherman, et al. (1997), in a MacArthur successful aging study, noted the importance of perceived control as a stable variable, which is thereby a promising avenue for predicting outcomes in personality and aging research. They consequently studied two aspects of perceived control, locus of control and perceived competence, in older adults over a seven-month period. The authors showed: 1) “that the responses of a panel of older participants are structurally consistent with dominant conceptions of perceived control and that the responses maintain an underlying structure over the frequently repeated protocol”; and 2) “the within-person variation over weekly measurements is coherent information rather than ‘noise’ and that individual differences in magnitude of week-to-week variability are a relatively stable attribute that predicts mortality status 5 years later” (p. 489).
Another study (Meeks & Murrell, 2001) assessed the relationship among two enduring attributes, educational attainment and negative affect, and two indicators of successful aging, health and life satisfaction. It found that lower levels of trait negative affect was related to higher educational attainment, and that lower negative affect resulted in better health and life satisfaction. Harris and Dollinger (2003) focused on anxiety about aging, and its relation to the Big Five Personality traits. Anxiety about aging was related to neuroticism, inversely related to agreeableness, conscientiousness, and extraversion, and unrelated to openness to experience. The authors said these results “support the notion that anxiety about aging is related to individual differences in personality traits,” and suggested that certain aspects of anxiety about aging may be relatively stable (p. 187).
Forgiveness is another personality factor that has been examined with relation to successful aging; Lawler-Row and Piferi (2006) found that trait forgiveness was associated with subjective well-being, depression, and stress, and that forgiveness was related to six dimensions of successful aging. Additionally, Romero and Mitchell (2004), in their study of younger and older Roman Catholic women, found that older women were more likely to respond to interpersonal conflicts with forgiveness, and they suggested that their results support models of successful aging.
Ska and Joanette (2006) suggested that personality is one factor among many (e.g., educational level, health, cognitive style, life style) that explain age-related cognitive change, in that it influences attentional resources and cerebral plasticity. Gangbe and Ducharme (2006, p. 297) contrasted “less modifiable personality traits” with other factors that can be mobilized and learned, such as social and personal resources.
The personality traits of centenarians’ offspring may offer an important direction in assessing genetic and environmental influences of longevity and successful aging (Givens et al., 2009). Similarities across four of the five domains (neuroticism, extraversion, openness, agreeableness, and conscientiousness) between male and female offspring were found to be noteworthy.
Another personality typology – resilients, undercontrollers, and overcontrollers – was utilized in a study of 735 elderly Italian adults (Steca, Alessandri, Caprara, 2010). Researchers found that “the three prototypes clearly differed in terms of their life and health satisfaction, positive affectivity, interpersonal trust, civic and social engagement and leisure activities,” with resilients showing the most positive profile (p. 442).
Finally, Giblin (2011) defined wisdom and despair as choices for cognitively intact older adults. She described constructs of personality as they relate to this topic.
John Rowe and Robert Kahn: Health Promotion and Disease Prevention
Rowe and Kahn (1987) offered numerous recommendations for future directions in successful aging research. They summarized them by stating that their recommendations “…have in common a thrust toward health promotion and disease prevention in the elderly. A revolutionary increase in life span has already occurred. A corresponding increase in health span, the maintenance of full function as nearly as possible to the end of life, should be the next gerontological goal” (p. 149). Accordingly, the search terms “successful aging” and “health promotion” produced 26 results in Web of Science; “successful aging” and “disease prevention” produced five results. Twenty-one of those articles were particularly responsive to Rowe and Kahn’s recommendations.
One of the earlier articles was authored by Rowe and Kahn (2000) and serves as an addendum to their three-pronged successful aging model. They suggested resilience and wisdom as two additional research domains, and proposed a national initiative in health promotion and disease prevention.
Additionally, Rowe and Kahn’s successful aging model provided a framework for HealthStages, a comprehensive health promotion program of OASIS, a national arts and humanities, health, and volunteer organization for older adults. Everard, Lach, and Heinrich (2000) explained the development of HealthStages and compared participants to a random sample of older adults in terms of health, health behavior, healthcare utilization activity, and functioning over time.
Drewnowski et al. (2003) asserted that Rowe and Kahn’s definition of successful aging required that health-related quality of life be a key goal for nutrition and physical activity programs targeted toward the elderly. They consequently reviewed the relationship between health parameters and health-related quality of life, and assessed existing screening and promotion programs.
Another model that has been tested to explore the long-term benefits of engaging in proactive health promotion efforts was the Preventive and Corrective Proactivity (PCP) Model of Successful Aging (Kahana et al., 2002). Kahana et al. concluded that, among the old-old, “exercise had long-term and multifaceted benefits over an 8-year period. Tobacco avoidance also contributed to long-term positive outcomes. These results lend support to the long-term preventive value of health-promoting proactivity spontaneously engaged in by old-old persons proposed in the framework of the PCP model” (p. 382). Kahana, Kahana, and Zhang (2005) also looked at motivational antecedents of preventive proactivity in late life, finding that future-oriented thinking has a lasting impact on health promotion behavior, and thus represents a dispositional antecedent of preventive proactivity.
Topp, Fahlman, and Boardley (2004) focused on two lifestyle choices that have been demonstrated to improve musculoskeletal and cardiovascular functioning and reduce symptoms of chronic disease: increased physical activity and appropriate nutritional intake. Higgs and Quirk (2007) likewise noted that “Nutrition, exercise, and social environment all interact to promote, or to limit, opportunities for an active and healthy post-working life” (p. 251). Their paper examined the example of a group of older Australians who chose to use their later years and retirement as opportunities for travel and leisure and discussed whether these “grey nomads” (similar to North American “snowbirds”) represent a good model for improving health-related lifestyles in later life.
Maharishi Vedic Medicine (MVM), a comprehensive, sophisticated system of natural medicine, has been identified via literature review as particularly effective in retarding usual aging (Schneider et al., 2002). Its efficacy in reducing physiological and psychological stress and enhancing homeostatic and self-repair processes are the proposed mechanisms for MVM’s anti-aging effects. Thus, the authors suggested that health objectives for disease prevention and health promotion in older adults might be achieved with widespread implementation of MVM.
With regard to disease prevention, Syme (2003) noted that interventions aimed at changing high-risk behavior have not been very successful, and consequently offered disease prevention programs as a potential solution. However, he stated, “to develop more effective prevention programs, we will have to train a new generation of experts who can not only provide people with risk information but also work with them as partners in achieving mutually agreed upon goals” (p. 400).
Anetzberger (2002) surveyed community resources for older people, such as wellness programs, home health care, mental health services, senior centers, adult day care, senior housing, employment services, learning experiences, and volunteer programs. Such resources provide opportunities for the promotion of health and successful aging.
In a study of Italian people aged 50-75 years enrolled in a health promotion program, Lucchetti, Spazzafumo, and Cerasa (2001) identified the most important variables defining lifestyle, in order to select a group of elderly with a “correct” lifestyle. They concluded that “the principal outcome concerns the overwhelming role played by the subjective perception of aging. It is, therefore, necessary for social policies to concentrate on the importance of promoting educational campaigns for the achievement of successful aging, stressing the value of both personal well-being and socializing activities” (p. 439).
In terms of measuring various aspects of health-related lifestyle in older adults, a self-report measure has been developed: the Health Enhancement Lifestyle Profile (HELP). HELP consists of seven scales and was examined for reliability and validity by Hwang in 2010. Internal consistency reliability was acceptable to good and construct validity was supported. Hwang concludes that “HELP scales can help occupational therapists identify and monitor health promotion occupations and risk behaviors and measure the outcome of services aimed at promoting healthy lifestyles in older adults” (p. 158).
Spirituality is the focus of some studies in the health promotion-successful aging realm. In a two-part study, Parker et al. (2001a, 2001b) advocated a conceptual model that links common goals across the fields of successful aging, health promotion, spirituality and health, and life course as an improved health promotion strategy for the Department of Defense. Parker et al. (2002) described a multichurch-sponsored conference that hosted over 500 seniors. Faculty from academic, medical, state, and religious institutions presented a variety of workshops involving a multidisciplinary model of health promotion, which incorporated spirituality into a successful aging intervention. With postconference surveys showing favorable satisfaction rates across all groups represented, the authors concluded that this model has the potential to unify various religious communities around the important task of promoting successful aging.
Crowther et al. (2002) called spirituality “the forgotten factor” in Rowe and Kahn’s model. They “offer evidence that links positive spirituality with health; describe effective partnerships between health professionals and religious communities; and summarize the information as a basis for strengthening the existing successful aging model proposed by Rowe and Kahn” (p. 613).
Particular areas of health promotion as they relate to successful aging have been investigated, such as oral health. Macentee, Hole, and Stolar (1997) interviewed 24 older adults in response to the question, “What is the significance of oral health in the lives of older adults?” Three interacting themes emerged – comfort, hygiene and health – which corresponded with more general theories of aging to offer guidance for health promotion and further research. Additionally, participants emphasized the need to adapt to and cope with oral disorders as an integral part of successful aging. Kiyak (2000, p. 276) noted the timeliness and importance of successful aging research, suggesting that “such a paradigm shift is critical in geriatric dentistry as well, where successful aging is evident in the growing number of older adults who have retained their natural dentition into advanced old age.” This conference presentation drew parallels between successful aging at the systemic and oral health levels, using epidemiologic studies to demonstrate trends in improved health and quality of life among newer cohorts of older adults.
Another specific health concern, renal disease, has been addressed by Blevins and Troutman (2011). They provided an overview of theory-based strategies for fostering successful aging in chronic renal disease patients by emphasizing health promotion and adaptation.
Promoting successful aging within the primary care setting was the focus of a study by Nakasato and Carnes (2006). The authors asserted that primary care providers can modify the pathology and mitigate the expression of the aging process, and thus call for increased physician mentoring and guidance to promote health in geriatric patients.
Finally, Harris (2008) took issue with the successful aging paradigm of health promotion. Instead, she suggested that the goal should be resilience, since “developing resilience is possible for many older adults regardless of social and cultural backgrounds or physical and cognitive impairments, unlike successful aging” (p. 43). Indeed, Rowe and Kahn (2000), as mentioned above, agreed that resilience should be a research domain.
Margrett and Paul Baltes: Subjective vs. Objective Criteria
The recommendations of Baltes and Baltes (1990) focus on the synthesis of both objective and subjective measurements: “…an encompassing definition of successful aging requires a value-based, systemic, and ecological perspective. Both subjective and objective indicators need to be considered within a given cultural context with its particular contents and ecological demands. However, both the objective aspects of medical, psychological and social functioning and the subjective aspects of life quality and life meaning seem to form a Gordian knot that no one is prepared to untie at the present time. Our suggested solution is to use multiple subjective and objective criteria and to explicitly recognize individual and cultural variations” (p. 7). The search terms “successful aging” and “subjective” and “objective” produced 14 results in Web of Science. Eight of those articles particularly address the issues raised by Baltes and Baltes.
Vaillant and Mukamal’s (2001) study on successful aging followed two cohorts of adolescent boys for 60 years or until death. They used four objectively assessed variables (physical health, death and disability before age 80, social supports, and mental health) and two self-rated variables (instrumental activities of daily living and life enjoyment) to assess successful aging at age 70-80. They found that that “good” and “bad” aging from age 70-80 could be predicted by variables assessed before age 50, and that depression was the only uncontrollable predictor variable that affected the quality of subjective and objective aging.
Montross et al. (2006) noted the lack of a definition of successful aging and thus asked the participants to rate their own degree of successful aging while also obtaining demographic characteristics, medical history, activity levels, resilience, daily functioning, and health-related quality of life. The authors concluded that “Most community-dwelling older adults viewed themselves as aging successfully despite having chronic physical illnesses and some disability. Longitudinal studies of the reliability and validity of subjective ratings of successful aging are warranted” (p. 43).
Hsu (2009) studied the effect of physical function trajectories on emotional health and subjective well-being among older adults in Taiwan. The author suggested that health policies incorporate coping strategies and supporting resources to help disabled elderly age successfully. Chinese elderly respondents were asked to define their own successful aging in a study by Lee (2009). Crucial predictors of participants’ self-reported successful aging were life satisfaction, sex, self-reported health status, satisfaction with living environment and major source of income.
In reviewing the definitions, determinants, and ways of enhancing successful cognitive and emotional aging, Jeste, Depp, and Vahia (2010) found that objective definitions of successful aging based on physical health emphasized outcomes (such as freedom from disability and disease), whereas subjective definitions focused on well-being, social connectedness, and adaptation. Additionally, although most older people do not meet objective criteria for successful aging, a majority do meet the subjective criteria.
Pruchno, Wilson-Genderson, and Cartwright (2010) proposed a two-factor model of successful aging that included objective and subjective components. They stated that “Confirmatory factor analyses provided support for a multidimensional model incorporating objective criteria and subjective perceptions. Age and gender were associated with objective but not subjective success” (p. 671).
Other studies have focused on a particular variable, such as exercise, or memory functioning. D’Epinay and Bickel (2003) state that “from a ‘successful aging’ perspective, the subjective feeling of well-being is as important as ‘objective’ health” (p. 155). Their study consequently looked at the relationship among four trajectories of exercise behavior and two indicators of well-being (self-rated health and self-assessed depression scale). They found that the long-term exerciser group had a higher level of well being than the quitter and the sedentary groups. Hohaus (2007) evaluated a memory enhancement program incorporating principles of successful aging, which was designed to enhance both objective and subjective everyday memory, and she described the results as promising.
Phelan and Larson: Self-Rating
According to Phelan and Larson (2002, p. 1307), “Future research in the area of successful aging should attempt to compare the definitions of successful aging of aging individuals themselves with those developed by the research community.” They further stated that a patient-centered definition is essential for future research. While “patient-centered definition” and “successful aging” did not produce any results, “successful aging” and “self-rating” produced two results in Web of Science.
Strawbridge, Wallhagen, and Cohen (2002) compared the utility of two different definitions of successful aging: self-rated versus criteria offered by Rowe and Kahn (absence of disease, disability, and risk factors; maintaining physical and mental functioning; and active engagement with life). For the purpose of predicting well-being, they made associations with well-being for each definition. The results showed that “The percentage of those rating themselves as aging successfully was 50.3% compared with 18.8% classified according to Rowe and Kahn’s criteria. Although absence of chronic conditions and maintaining functioning were positively associated with successful aging for both definitions, many participants with chronic conditions and with functional difficulties still rated themselves as aging successfully; none were so classified according to Rowe and Kahn’s criteria” (p. 727).
The other study pertaining to self-rating and successful aging examined the utility of a self-administered cognitive screening instrument and evaluated correlations of the performance on this measure with indicators of self-rated successful aging. Moore et al. (2007) found that, as expected, Cognitive Assessment Screening Test-Revised scores were positively correlated with a self-rating of successful aging. They cited this as a first step in establishing the validity of the CAST-R.
Glass: Synthesizing Biomedical and Psychosocial Schools
In 2003, Glass noted that the two distinct schools, psychosocial and biomedical, do not yet agree on a definition of successful aging. “We badly need a synthesis of these two approaches,” Glass wrote, “…we need to know considerably more about what older people value and how they define successful aging; we know next to nothing about these two subjects” (p. 382). The search terms “successful aging” and “biomedical” and “psychosocial” produced two results in Web of Science. The search terms “successful aging” and “biopsychosocial” produced five results in Web of Science. Six of those articles were responsive to Glass’s concerns.
Gangbe and Ducharme (2006) observed that although successful aging and related concepts are appealing, researchers are challenged by the lack of consensus with regard to models. Reviewing its definition, psychosocial determinants, and conceptual models, the authors reported that “the meaning of the concept varies according to the cultural context (individualistic/relational societies), to the actors’ perspectives (researcher/elderly) and according to the dominant approach (biomedical/holistic)” (p. 297). They stated that psychosocial factors are the most frequent determinants addressed by models, and suggested that the integration of the various models into one meta-model remains a task to be done.
Noting that most studies of successful aging use restricted definitions to identify a small number of predictors, Ng et al. (2009) measured multiple dimensions of functioning and wellness. Thus, “In contrast to findings based on more restricted biomedical definitions of successful aging, a multidimensional definition of successful aging identified more variables including demographic status, psychosocial support, spirituality, and nutrition as salient determinants” (p. 407).
Kubzansky et al. (1998) performed a cross-sectional analyses of psychosocial, behavioral, and biological factors, and educational attainment, using data from a population-based cohort study of older men and women, to investigate the association of educational attainment with shared determinants of health. They found that even in an older, healthy population, an education gradient functions over an array of factors that structure daily life.
Also mentioned above in the subjective-objective literature search, Vaillant and Mukamal’s (2001) study is notable here for the breadth of measurements utilized: “Complete physical examinations were obtained every five years and psychosocial data every two years. Predictor variables assessed before age 50 included six variables reflecting uncontrollable factors: parental social class, family cohesion, major depression, ancestral longevity, childhood temperament, and physical health at age 50 and seven variables reflecting (at least some) personal control: alcohol abuse, smoking, marital stability, exercise, body mass index, coping mechanisms, and education. The six outcome variables chosen to assess successful aging at age 70-80 included four objectively assessed variables (physical health, death and disability before age 80, social supports, and mental health) and two self-rated variables (instrumental activities of daily living and life enjoyment)” (p. 839).
Inui (2003) specifically addresses the need for an integrated biopsychosocial approach to research on successful aging. The author promotes a multi-method research agenda that is in effect a “natural science” of aging. Such an approach, Inui asserted, “…will be required to uncover and use information about linear, cause-and-effect phenomena, as well as about higher-order emergent patterns that are of relevance to the health of elderly persons, such as ‘resilience’ and ‘generativity’” (p. 391).
Finally, with regard to the biopsychosocial components of successful aging, Meisner et al. (2010) looked specifically at the effects of physical inactivity. The results reinforce that in later life even moderate levels of physical activity can help optimize biopsychosocial health, and in particular functional health.
Summary and Conclusions
The goal of this paper was to examine the future directions suggested by six germane articles, and in exploring literature searches based on these recommendations, develop an understanding of what has been addressed and what questions remain. Starting with measures and operational definitions, there is a wealth of literature in this area, and Havighurst’s suggestion of several different measures seems to have been fulfilled. But as addressed by Martin et al., the term “successful aging” is ambiguous. As a construct, successful aging requires a standardized definition before standardized measurement can be conducted. However, “Because of the multifactorial nature of the psychosocial and biomedical domains, there is no clear consensus on the definition of successful aging or its determinants” (Franklin & Tate, 2009).
While there is breadth and depth to successful aging research, different researchers are using a wide variety of measures, which in some ways dilutes the term “successful aging.” While a single, generally-accepted definition is not likely forthcoming, a fruitful research direction would be to identify the potential components of an encompassing definition. Havighurst’s suggestion of several different measures is as timely as ever, and such measures might be incorporated into a single broad model with numerous domains and subscales. Thus, regardless of whether a particular researcher agrees or disagrees with certain elements of the model, there is a single point of reference, which would likely increase collaborative efforts and consequential progress.
Since successful aging encompasses numerous factors, it would be helpful to understand the interaction of personality traits with those factors. Neugarten’s suggestion that personality be afforded central importance when considering successful aging, however, does not appear to have been fulfilled. Perhaps the most promising direction emphasizing a focus on personality includes research on resilience (Fry & Kyes, 2010). Future directions at the intersection of successful aging and personality could address the potential to maximize an individual’s potential given particular personality traits or, conversely, the ability of an individual to modify pliable traits that are not compatible with successful aging.
If any researchers’ names are synonymous with successful aging it is Rowe and Kahn, and their model has had an obvious impact on the trajectory of successful aging studies. A major strength of Rowe and Kahn’s work is the explicit definition they provide; however, the other side of that coin is that this definition is (by necessity) exclusionary. A frequently-heard criticism of the Rowe and Kahn model is its imposition of certain values upon aging people, and thus the lack of subjective measures, which is addressed by the following researchers.
Thus, Baltes and Baltes’ suggestions address both measurement and subjective dimensions. With Rowe and Kahn focusing on objective dimensions, it seems a natural progression that consequent inquiries would question the lack of a subjective dimension. Further calling for a role for subjective components were Phelan and Larson.
Finally, we come full circle with Glass’s appeal to synthesize the biomedical and psychosocial approaches while considering what older people value. This search produced Gangbe and Ducharme’s article, which stated that a meta-model is a remaining task — as we have proposed above in relation to Havighurst’s suggestions.
Of course, there are numerous limitations to this bibliography and its approach. The choice of the six pieces of literature (four seminal articles and two review articles) involved the authors’ judgment, and certainly there are other pertinent articles that could have been chosen, with differing results. Similarly, the search terms chosen to represent these articles’ key thematic passages were based on researchers’ judgments, and in some cases were selected for their ability to produce a reasonable universe of data through which to comb. Additionally, only the Web of Science database was searched, and other databases would have most likely produced differing results. However, we feel this approach was methodical and produced a meaningful basis for discussion and for guiding future research.
The results can be viewed as a natural evolution of the concept of “successful aging” in gerontology. What began as a novel departure from the prevailing “disease model” is now a familiar and useful framework for both theories and applications, from individual well-being to longevity to public policy. The next generation of successful aging researchers would be well-served by a broad, inclusionary model that is explicit about definition and measurement, perhaps organized via a web-based information architecture approach. From such a model (and versions thereof), researchers could focus on a particular domain while also conveying how it relates to the whole of “successful aging.”
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