Intrinsic capacity rather than intervention exposure influences reversal to robustness among prefrail community-dwelling older adults: A non-randomized controlled study of a multidomain exercise and nutrition intervention

Development and validation of an intrinsic capacity score in the UK Biobank study

BACKGROUND

In 2015, the World Health Organization introduced the concept of intrinsic capacity (IC) to define the individual-level characteristics that enable an older person to be and do the things they value. This study developed an intrinsic capacity score for UK Biobank study participants and validated its use as a tool for health outcome prediction, understanding healthy aging trajectories, and genetic research.

METHODS

Our analysis included data from 45,208 UK biobank participants who had a complete record of the ten variables included in the analysis. Factor adequacy was tested using Kaiser-Meyer-Olkin, Barthelt's, and the determinant of matrix tests, and the number of factors was determined by the parallel analysis method. Exploratory and confirmatory factor analyses were employed to determine the structure and dimensionality of indicators. Finally, the intrinsic capacity score was generated, and its construct and predictive validities as well as reliability were assessed.

RESULTS

The factor analysis identified a multidimensional construct comprising one general factor (intrinsic capacity) and five specific factors (locomotor, vitality, cognitive, psychological, and sensory). The bifactor structure showed a better fit (comparative fit index = 0.995, Tucker Lewis index = 0.976, root mean square error of approximation = 0.025, root mean square residual = 0.009) than the conventional five-factor structure. The intrinsic capacity score generated using the bifactor confirmatory factor analysis has good construct validity, as demonstrated by an inverse association with age (lower intrinsic capacity in older age; (β) =-0.035 (95%CI: -0.036, -0.034)), frailty (lower intrinsic capacity score in prefrail participants, β = -0.104 (95%CI: (-0.114, -0.094)) and frail participants, β = -0.227 (95%CI: -0.267, -0.186) than robust participants), and comorbidity (a lower intrinsic capacity score associated with increased Charlson's comorbidity index, β =-0.019 (95%CI: -0.022, -0.015)). The intrinsic capacity score also predicted comorbidity (a one-unit increase in baseline intrinsic capacity score led to a lower Charlson's comorbidity index, β = 0.147 (95%CI: -0.173, -0.121)) and mortality (a one-unit increase in baseline intrinsic capacity score led to 25 % lower risk of death, odds ratio = 0.75(95%CI: 0.663, 0.848)).

CONCLUSION

The bifactor structure showed a better fit in all goodness of fit tests. The intrinsic capacity construct has strong structural, construct, and predictive validities and is a promising tool for monitoring aging trajectories.

Reference centiles for intrinsic capacity throughout adulthood and their association with clinical outcomes: a cross-sectional analysis from the INSPIRE-T cohort

Intrinsic capacity (IC), a function-centered construct, is defined as the composite of all physical and mental capacities of an individual. IC and surrounding environmental factors determine an individual's functional ability to do what they want or feel valued. Current literature lacks evidence on how IC varies throughout adulthood. In this study, we demonstrated a method to establish age-specific and sex-specific reference centiles for IC using the Human Translational Research Cohort of the INSPIRE Platform (975 adults, aged 20-102 years, living in the southwest France, Toulouse area). IC was operationalized as the mean score of the five key domains (cognition, locomotion, psychology, sensory and vitality) and the factor score from a bifactor model, respectively. Both IC operationalizations showed higher IC levels in young and middle age and markedly lower levels after age 65 years, with greater inter-individual variation in old age than in youth. Individuals with IC ≤10th percentile tended to have high comorbidity, prefrailty/frailty, difficulties in basic and instrumental activities of daily living and falls than individuals with IC >90th percentile. These findings suggest that IC reference centiles can help monitor the functional capacity of individuals during aging, similar to tracking children's development with growth charts.

Multidimensional interventions to increase life-space mobility in older adults ranging from nursing home residents to community-dwelling: a systematic scoping review

BACKGROUND

Life-space mobility (LSM) is an important aspect of older adults' real-life mobility. Studies have shown that restricted LSM is a risk factor for many adverse outcomes such as low quality of life and mortality. Therefore, an increasing number of interventions aim to enhance LSM. However, the intervention approaches differ in terms of their type/content, duration, targeted populations, but also in terms of their outcome measures and assessment tools. Especially the latter impairs the comparability of studies with otherwise similar interventional approaches and thus also the interpretation of their results. Therefore, this systematic scoping review aims to provide an overview of the intervention components, assessment tools, and effectiveness of studies aiming to improve LSM in older adults.

METHODS

A systematic literature search was carried out in PubMed and Web of Science. We considered studies in older adults of any design that included an intervention approach and at least one outcome of LSM.

RESULTS

27 studies were included in the review. These studies analyzed healthy community-dwelling as well as frail older adults in need of care or rehabilitation and nursing home residents with a mean age between 64 and 89. The percentage of female participants ranged from 3 to 100%. The types of interventions were of the following: physical, counseling, multidimensional, miscellaneous. Multidimensional interventions consisting of physical interventions plus any of the following or a combination of counseling/education/motivation/information appear to be most effective in increasing LSM. Older adults with mobility impairments were more responsive to these multidimensional interventions compared to healthy older adults. Most of the studies used the questionnaire-based Life-Space Assessment to quantify LSM.

CONCLUSIONS

This systematic scoping review provides a comprehensive overview of a heterogenous stock of literature investigating LSM-related interventions in older adults. Future meta-analyses are needed to provide a quantitative evaluation of the effectiveness of LSM interventions and recommendations.

Effects of multi-domain intervention on intrinsic capacity in older adults: A systematic review of randomized controlled trials (RCTs)

Intrinsic capacity is central to the maintenance of function in older adults, and maintaining optimal intrinsic capacity is of great importance to promote healthy aging. The purpose of this systematic review and meta-analysis was to analyze the impact of multi-domain interventions on intrinsic capacity in older adults, intervention components, and potential interactions between components. A total of 6740 published articles were screened until August 2022, and the review included 25 randomized controlled trials that analyzed populations, interventions, control groups, and outcomes. The meta-analysis showed improvements in the primary outcome indicators in the intervention group compared to the control group. These included increased scores on the Mini-Mental State Examination as an indicator of cognitive function, decreased scores on the Geriatric Depression Scale (GDS-15) as an indicator of psychological ability and increased scores on the Short Physical Performance Battery (SPPB) as an indicator of physical performance, with only the SPPB indicator analyzed showing greater heterogeneity. Significant improvements were also seen in the secondary indicators Time-to-Walk Test (TUG), gait speed, Chair Stand Test (CST), grip strength values and BMI. There was insufficient data for the Mini Nutritional Assessment (MNA) as an indicator of vitality to conduct a meta-analysis. Studies were of moderate to high quality. The results of this review indicate that multi-domain interventions can maintain the level of intrinsic capacity in older adults and are equally effective in older adults with declining self-care abilities.