Exploring the relationship between intrinsic capacity and social participation in healthy ageing: Evidence from Singapore

Zhang C., Zhao Y., Chen X., Li X., Liu Q., Peng R., Chen Y., Feng H.

Social participation is a key factor in achieving active aging. This study aimed to explore the trajectories and predictors of social participation changes among older adults in China. The data used in this study are from the ongoing national longitudinal study CLHLS. A total of 2492 older adults from the cohort study were included. Group-based trajectory models (GBTM) were used to identify potential heterogeneity in longitudinal changes over time and investigate associations between baseline predictors and trajectories for different cohort members using logistic regression. Four different trajectories of social participation were reported in older adults, namely, stable (8.9%), slow decline (15.7%), lower score with decline (42.2%), and higher score with decline (9.5%). On multivariate analyses, age, years of schooling, pension, mental health, cognitive function, instrumental activities of daily living, and initial social participation scores significantly impact the rate of change in social participation over time. Four trajectories of social participation were identified in the Chinese elderly population. Management of mental health, physical function, and cognitive function appear to be important in maintaining the long-term social participation of older people in the community. Early identification of factors influencing the rapid decline in social participation and timely interventions can maintain or improve social participation levels in older adults.

Jia S., Zhao W., Ge M., Xia X., Hu F., Hao Q., Zhang Y., Yang M., Yue J., Dong B.

Abstract Background The trajectory of frailty and intrinsic capacity (IC) often overlap in older adults. Longitudinal analyses of transitions of frailty and IC, and their associations with incident functional decline are limited. The present study aimed to identify transitions of frailty status and IC, and explore associations between transitions of frailty and IC, and future disability among community-dwelling older adults. Methods In the West China and Aging Trend Study, 808 participants aged ≥ 60 years completed baseline and three years follow-up (frailty, IC and disability assessments). Physical frailty was measured based on Fried phenotype. IC was evaluated by five domains (cognition, locomotion, sensory, psychological, and vitality). Disability was defined as a need for assistance in any items in activity of daily living (ADL) or the instrumental activity of daily living (IADL). Logistic regressions were performed to examine their relationships. Results Four transitions of IC status (kept well: 27.4%, improved: 8.4%, worsened: 35.4%, and kept poor: 28.8%), and two transitions of frailty status (kept not-frail/improved: 93.2%, kept frail/worsened: 6.8%) were identified. Impaired locomotion and vitality at baseline were significantly associated with kept frail or worsened frail. However, impaired sensory and vitality at baseline not frailty status was significantly associated with transitions of IC. Adjusted for covariates and transitions of frailty, kept poor IC was associated with ADL (OR = 2.26, 95%CI = 1.17,4.34) and IADL disability (OR = 3.74, 95%CI = 1.79, 7.82). Conclusions Transitions of IC, but not frailty were associated with higher risk of incident disability. Baseline locomotion and vitality impairment were associated with worsened or kept frail. Our findings support the WHO’s notion of monitoring and optimizing IC to delay deterioration of IC and preventing frailty and disability. Clinical trial number ChiCTR1800018895

Zhou J., Chang H., Leng M., Wang Z.

Objective: Intrinsic capacity is recognized as an important determinant of healthy aging and well-being of older adults; however, relatively little is known about the intrinsic capacity of older adults to predict adverse health outcomes. The study aimed to examine which adverse health outcomes of older adults can be predicted by intrinsic capacity. Methods: The study was conducted using the scoping review methodological framework of Arksey and O’Malley. A systematic literature search of nine electronic databases (i.e., Pubmed, Embase, Cochrane library, Web of science, CINAHL, China National Knowledge Infrastructure, VIP, Wanfang, and the Chinese Biological Medical Literature Database) were performed from the database’s inception to 1 March 2022. Results: Fifteen longitudinal studies were included. A series of adverse health outcomes were assessed, including physical function (n = 12), frailty (n = 3), falls (n = 3), mortality (n = 6), quality of life (n = 2) and other adverse health outcomes (n = 4). Conclusions: Intrinsic capacity could predict some adverse health outcomes of different follow-up times for older adults; however, due to the small number of studies and sample size, more high-quality studies are necessary to explore the longitudinal relationships between intrinsic capacity and adverse health outcomes in the future.

Campbell C.L., Cadar D., McMunn A., Zaninotto P.

Abstract Background Intrinsic capacity (IC) is a new concept in the healthy ageing field and has many operationalised definitions. In this study, we operationalised IC using item response theory in the English Longitudinal Study of Ageing (ELSA) and tested the predictive value of the scale using subsequent functional ability, mortality, and hospital admission. Methods IC was measured at baseline (2004, Wave 2) using 14 dichotomous indicators: word recall, orientation in time, balance, chair rises, walking speed, upper mobility, lower mobility, eyesight, hearing, grip strength, BMI, waist circumference, depressive symptoms, life satisfaction. A two-parameter item response theory model was used to generate a scale of IC at baseline. Logistic regression was used for the prediction of subsequent difficulties, measured by difficulties with ≥1 activities of daily living (ADLs) and ≥1 instrumental activities of daily living (IADLs) at 4 and 8 years after baseline. Competing risk and cox regressions were employed to test prediction of hospital admission and mortality, respectively, over a 14-year follow-up. Results Intrinsic capacity scores were generated for 4,545 individuals aged on average 70.8 years (SD 7.93). Better baseline IC scores were associated with reduced risk of subsequent difficulties with ADLs and IADLs, hospital admission (SHR=0.99, 95%CI 0.98-0.99) and mortality (HR=0.98, 95%CI 0.98–0.99), when adjusted for sociodemographic and health-related covariates. Conclusions These results suggest the utility of this IC score as a measure of risk for future adverse outcomes in older people, potentially above that indicated by other sociodemographic and health-related factors.

Lee J.Q., Ding Y.Y., Latib A., Tay L., Ng Y.S.

ObjectivesTo examine the association of intrinsic capacity (IC) with life-space mobility (LSM) among community-dwelling older adults and to determine whether age and gender modify this relationship.DesignCross-sectional study.SettingPublic housing blocks, senior activity centres and community centres in the Northeastern region of Singapore.Participants751 community-dwelling older adults aged ≥55 years old and able to ambulate independently with or without walking aid.Primary and secondary outcome measuresIC and LSM. Standardised IC factor scores were calculated through confirmatory factor analysis using variables representing the five IC domains cognition, locomotion, sensory, vitality and psychological. LSM was measured using the University of Alabama at Birmingham Study of Aging Life-Space Assessment instrument. Association of IC with LSM and its effect modification by age and gender were examined with regression analyses.ResultsThe participants had a mean age of 67.6 and mean LSM score of 88.6. IC showed a positive and significant association with LSM (β=6.33; 95% CI=4.94 to 7.72) and the effect remained significant even after controlling for potential confounders (β=4.76; 95% CI=3.22 to 6.29), with p<0.001 for both. Age and gender did not demonstrate significant modification on this relationship.ConclusionsOur findings support the empirical rigour of the International Classification of Functioning, Disability and Health framework, which suggests that IC influences the extent to which a person participates in the community. Our findings also provide guidance for healthcare providers who aim to enhance LSM and promote healthy ageing in older adults.

Stolz E., Mayerl H., Freidl W., Roller-Wirnsberger R., Gill T.M.

Abstract Background Monitoring trajectories of intrinsic capacity (IC) in older adults has been suggested by the World Health Organization as a means to inform prevention to avoid or delay negative health outcomes. Due to a lack of longitudinal studies, it is currently unclear how IC changes over time and whether repeatedly measured IC predicts negative health outcomes. Methods Based on 4 751 repeated observations of IC (range = 0–100) during 21 years of follow-up among 754 older adults 70 and older, we assessed longitudinal trajectories of IC, and whether time-varying IC predicted the risk of chronic activities of daily living disability, long-term nursing home stay, and mortality using joint models. Results Average IC declined progressively from 77 to 11 points during follow-up, with substantial heterogeneity between older adults. Adjusted for sociodemographics and chronic diseases, a 1-point lower IC value was associated with a 7% increase in the risk of activities of daily living disability, a 6% increase in the risk of a nursing home stay, and a 5% increase in mortality. Accuracy for 5- and 10-year predictions based on up to 3 repeated measurements of IC ranged between moderate and good (area under the receiver operating characteristic curve = 0.76–0.82). Conclusions Our study indicates that IC declines progressively and that it predicts negative health outcomes among older adults. Therefore, regular monitoring of IC could work as an early warning system informing preventive efforts.

Lau S., Pek K., Chew J., Lim J.P., Ismail N.H., Ding Y.Y., Cesari M., Lim W.S.

Malnutrition is an independent marker of adverse outcomes in older adults. While the Simplified Nutritional Appetite Questionnaire (SNAQ) for anorexia has been validated as a nutritional screening tool, its optimal cutoff and validity in healthy older adults is unclear. This study aims to determine the optimal cutoff for SNAQ in healthy community-dwelling older adults, and to examine its factor structure and validity. We studied 230 community-dwelling older adults (mean age 67.2 years) who were nonfrail (defined by Fatigue, Resistance, Ambulation, Illnesses & Loss (FRAIL) criteria). When compared against the risk of malnutrition using the Mini Nutritional Assessment (MNA), the optimal cutoff for SNAQ was ≤15 (area under receiver operating characteristic (ROC) curve: 0.706, sensitivity: 69.2%, specificity: 61.3%). Using exploratory factor analysis, we found a two-factor structure (Factor 1: Appetite Perception; Factor 2: Satiety and Intake) which accounted for 61.5% variance. SNAQ showed good convergent, discriminant and concurrent validity. In logistic regression adjusted for age, gender, education and MNA, SNAQ ≤15 was significantly associated with social frailty, unlike SNAQ ≤4 (odds ratio (OR) 1.99, p = 0.025 vs. OR 1.05, p = 0.890). Our study validates a higher cutoff of ≤15 to increase sensitivity of SNAQ for anorexia detection as a marker of malnutrition risk in healthy community-dwelling older adults, and explicates a novel two-factor structure which warrants further research.

Gonzalez-Bautista E., Andrieu S., Gutiérrez-Robledo L.M., García-Chanes R.E., De Souto Barreto P.

Intrinsic capacity is a composite of five domains that summarizes the physical and mental capacities of an individual. Intrinsic capacity is increasing in relevance for adapting health systems to population ageing. Therefore, our objective was to analyse how intrinsic capacity has been assessed in older adults and if these measurements have been validated, as an initial step towards the construction of a standard intrinsic capacity index. Narrative review with electronic searches performed in PubMed and Cochrane databases, including the studies which used the term “intrinsic capacity” in the context of human ageing and health. The full text was then accessed to select studies with at least one operationalised domain of intrinsic capacity. We also looked for information on the validity and reliability of the reported measures of intrinsic capacity. We included ten articles reporting a quantitative measurement of intrinsic capacity. There were two intrinsic capacity scores which combined retrospective data on the intrinsic capacity domains sub-scores, with low concordance among tests chosen to measure each domain. Two studies reported on reliability and validity of the IC scores. The main gaps in the construction and validation process were a) analysis undertaken with each domain separately rather than for the construct of intrinsic capacity, b) lack of a clear conceptual and operational definition of the vitality domain, c) summary score that depends upon the distribution of the study sample. Further validation of the intrinsic capacity concept is needed, together with more robust approaches to measure it. A standard index of IC has not been validated for translation into clinical or research purposes.

Makino K., Lee S., Bae S., Shinkai Y., Chiba I., Shimada H.

Early prevention of mild cognitive impairment MCI is crucial because individuals with MCI are at high risk for progression to dementia. The purpose of the present study was to examine the relationship between the performance of instrumental activities of daily living IADL and future incidence of MCI among community-dwelling older adults in Japan. A total of 1595 individuals without cognitive impairment at baseline participated in this prospective cohort study with a 48-month follow-up period. Performance on the following IADL was assessed at baseline: handling cash and banking, shopping for necessities, going out using buses/trains, using maps to travel to unfamiliar places, and operating video/DVD players. Objective cognitive screening using the National Center for Geriatrics and Gerontology-Functional Assessment Tool and Mini-Mental State Examination was conducted at baseline and follow-up; new MCI incidence over the 48 months was determined. Of all participants, 922 (57.8 %) had a limitation in at least one IADL at baseline. During the follow-up period, 179 (11.2 %) participants experienced a transition from normal cognition to MCI. Participants who had not engaged in "going out using buses/trains" or "using maps to travel to unfamiliar places" at baseline showed a significantly higher risk of MCI incidence than those who had engaged in such activities. Limitations in outdoor IADL were associated with MCI onset. Individuals with such limitations need to be monitored, as these limitations are strong indicators of cognitive decline and MCI.

Beard J.R., Jotheeswaran A.T., Cesari M., Araujo de Carvalho I.

ObjectivesTo assess the validity of the WHO concept of intrinsic capacity in a longitudinal study of ageing; to identify whether this overall measure disaggregated into biologically plausible and clinically useful subdomains; and to assess whether total capacity predicted subsequent care dependence.DesignStructural equation modelling of biomarkers and self-reported measures in the English Longitudinal Study of Ageing including exploratory factor analysis, exploratory bi-factor analysis and confirmatory factor analysis. Longitudinal mediation and moderation analysis of incident care dependence.SettingsCommunity, United Kingdom.Participants2560 eligible participants aged over 60 years.Main outcome measuresActivities of daily living (ADL) and instrumental activities of daily living (IADL).ResultsOne general factor (intrinsic capacity) and five subfactors emerged: locomotor, cognitive; psychological; sensory; and ‘vitality’. This structure is consistent with biological theory and the model had a good fit for the data (χ2=71.2 (df=39)). The summary score of intrinsic capacity and specific subfactors showed good construct validity. In a causal path model examining incident loss of ADL and IADL, intrinsic capacity had a direct relationship with the outcome—root mean square error of approximation (RMSEA)=0.02 (90% CI 0.001 to 0.05) and RMSEA=0.008 (90% CI0.001 to 0.03) respectively—and was a strong mediator for the effect of age, sex, wealth and education. Multimorbidity had an independent direct relationship with incident loss of ADLs but not IADLs, and also operated through intrinsic capacity. More of the indirect effect of personal characteristics on incident loss of ADLs and IADLs was mediated by intrinsic capacity than multimorbidity.ConclusionsThe WHO construct of intrinsic capacity appears to provide valuable predictive information on an individual’s subsequent functioning, even after accounting for the number of multimorbidities. The proposed general factor and subdomain structure may contribute to a transformative paradigm for future research and clinical practice.

Cesari M., Araujo de Carvalho I., Amuthavalli Thiyagarajan J., Cooper C., Martin F.C., Reginster J., Vellas B., Beard J.R.

Healthy ageing can be defined as "the process of developing and maintaining the functional ability that enables wellbeing in older age". Functional ability (i.e., the health-related attributes that enable people to be and to do what they have reason to value) is determined by intrinsic capacity (i.e., the composite of all the physical and mental capacities of an individual), the environment (i.e., all the factors in the extrinsic world that form the context of an individual's life), and the interactions between the two. This innovative model recently proposed by the World Health Organization has the potential to substantially modify the way in which clinical practice is currently conducted, shifting from disease-centered toward function-centered paradigms. By overcoming the multiple limitations affecting the construct of disease, this novel framework may allow the worldwide dissemination of a more proactive and function-based approach toward achieving optimal health status. 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 this article, we consider intrinsic capacity. Using the International Classification of Functioning, Disability and Health (ICF) framework as background and taking into account available evidence, five domains (i.e., locomotion, vitality, cognition, psychological, sensory) are identified as pivotal for capturing the individual's intrinsic capacity (and therefore also reserves) and, through this, pave the way for its objective measurement.

Wilkie R., Blagojevic-Bucknall M., Belcher J., Chew-Graham C., Lacey R.J., McBeth J.

AbstractIn older adults, reduced social participation increases the risk of poor health-related quality of life, increased levels of inflammatory markers and cardiovascular disease, and increased mortality. Older adults frequently present to primary care, which offers the potential to deliver interv

Beard J.R., Officer A., de Carvalho I.A., Sadana R., Pot A.M., Michel J., Lloyd-Sherlock P., Epping-Jordan J.E., Peeters G.M., Mahanani W.R., Thiyagarajan J.A., Chatterji S.

Although populations around the world are rapidly ageing, evidence that increasing longevity is being accompanied by an extended period of good health is scarce. A coherent and focused public health response that spans multiple sectors and stakeholders is urgently needed. To guide this global response, WHO has released the first World report on ageing and health, reviewing current knowledge and gaps and providing a public health framework for action. The report is built around a redefinition of healthy ageing that centres on the notion of functional ability: the combination of the intrinsic capacity of the individual, relevant environmental characteristics, and the interactions between the individual and these characteristics. This Health Policy highlights key findings and recommendations from the report.

Beard J.R., Officer A.M., Cassels A.K.

Nguyen T.Q., Webb-Vargas Y., Koning I.M., Stuart E.A.

We investigate a method to estimate the combined effect of multiple continuous/ordinal mediators on a binary outcome: 1) fit a structural equation model with probit link for the outcome and identity/probit link for continuous/ordinal mediators, 2) predict potential outcome probabilities, and 3) compute natural direct and indirect effects. Step 2 involves rescaling the latent continuous variable underlying the outcome to address residual mediator variance/covariance. We evaluate the estimation of risk-difference- and risk-ratio-based effects (RDs, RRs) using the ML, WLSMV and Bayes estimators in Mplus. Across most variations in path-coefficient and mediator-residual-correlation signs and strengths, and confounding situations investigated, the method performs well with all estimators, but favors ML/WLSMV for RDs with continuous mediators, and Bayes for RRs with ordinal mediators. Bayes outperforms WLSMV/ML regardless of mediator type when estimating RRs with small potential outcome probabilities and in two other special cases. An adolescent alcohol prevention study is used for illustration.