Socioeconomic differences in handgrip strength and its association with measures of intrinsic capacity among older adults in six middle-income countries

The relationship between muscle strength and epicardial fat in healthy adults

BACKGROUND

Muscular strength and muscle mass are considered key factors for healthy ageing. Modification of body composition and redistribution of adipose tissue has been described in advanced age. Muscle strength has an important predictive role for health outcomes. However, little is known regarding the relationship between muscle strength and epicardial fat.

METHODS AND MATERIALS

In a cohort of healthy adults following physical capacity evaluations, anthropometric measurements, handgrip strength (HGS), echocardiography and bioimpedance analysis (BIA) were performed. Kruskal-Wallis test, Spearman's correlation and regression analysis adjusted for confounders were applied.

RESULTS

A total population of 226 adults, age range 18-83 years, were included. Epicardial fat thickness resulted significantly associated with age p < 0.001, HGS (p < 0.001). Regression analysis adjusted for confounders revealed an independent relationship between handgrip strength and epicardial fat thickness: regression coefficient: -1.34; R2 = 0.27 and p = 0.044.

CONCLUSIONS

The relationship between epicardial fat and muscle strength is inverse and independent. Implementation of HGS measurement may be useful for the identification of subjects with excessive epicardial fat and cardiovascular risk. Measurement of epicardial fat could be helpful in the early detection of physical decline associated to ageing.

Social Determinants of Intrinsic Capacity: A National Cohort Study

INTRODUCTION

Intrinsic capacity (IC), a composite of physical and mental capacities, is a marker of healthy aging. Social determinants of health (SDOH), namely the economic and social environments across a lifespan, are the most fundamental factors influencing health outcomes and health disparities. However, there is limited evidence on the influence of the individual and combined burden of the SDOH on IC.

METHODS

Data were obtained from the China Health and Retirement Longitudinal Study (2011-2015), and data analysis was conducted in 2023. Linear mixed-effect regression was employed to investigate the association between SDOH and IC in a longitudinal analysis.

RESULTS

This study comprised 7,669 participants (mean [SD] age, 68.5 [7.1] years; 49.8% female; mean [SD] IC, 7.2 [1.6]). In the longitudinal analysis, all five SDOH domains were independently and significantly associated with IC. The absence of social association within the social and community context domain exhibited the weakest association with IC (β: -0.11 [95% CI -0.20, -0.02]), while illiteracy within the education access and quality domain demonstrated the strongest association with IC (β: -0.51 [95% CI -0.60, -0.42]). Furthermore, the adverse effects of SDOH on IC became more distinguishable with the cumulative number of SDOH variables (coefficient for 2 SDOH, -0.41 [-0.64, -0.19]; 3 SDOH, -0.70 [-0.93, -0.48]; ≥4 SDOH, -1.10 [-1.33, -0.88]) compared with those without any SDOH.

CONCLUSIONS

Certain SDOH levels were significantly and negatively associated with IC. Targeted interventions may be needed to improve SDOH in individuals at high risk of poor IC.

Association between Multimorbidity and Psychological Distress among Older Adults in India: The Moderating Role of Elder Abuse

OBJECTIVES

In this study, we examine the association between multimorbidity and psychological distress and to what extent elder abuse mediates the association.

METHODS

We analyzed cross-sectional nationally representative data from the "Building Knowledge Base on Population Ageing in India (BKPAI)." Multivariate logistic regression was used to understand the association between multimorbidity and psychological distress. We used Karlson-Holm- Breen (KHB) method to understand the role of elder abuse in mediating the association between multimorbidity and psychological distress.

RESULTS

Older adults who ever experienced abuse (OR = 1.92 95%CI = 1.62, 2.26, p < .001) or in last one month (OR = 2.09 95%CI = 1.65, 2.64, p < .001) reported higher odds of psychological distress. Further, older adults with four or more chronic diseases are thrice more likely to report psychological distress (OR = 3.03 95%CI = 2.38, 3.82, p < .001). The results further suggest the mediating role of abuse on the association between multimorbidity and psychological distress.

CONCLUSIONS

The results suggest the role of elder abuse on the association between multimorbidity and psychological distress among older population in India.

CLINICAL IMPLICATIONS

Creating an environment to reduce the abuse among older adults who have multimorbidity will be essential to reducing the psychological distress among older adults in India.

Examining factors contributing to the socioeconomic inequalities in handgrip strength among older adults in India: a decomposition analysis

The purpose of this study was to examine (a) the socioeconomic status (SES)-related inequalities associated with handgrip strength (HGS); and (b) the extent to which several demographic, health, and behavioral factors contributed to such SES disparities in HGS among older adults in India. Data were drawn from the 2017-2018 wave 1 of the Longitudinal Ageing Study of India (LASI). The study sample included 27,707 older adults (13,199 men and 14,508 women) aged 60 years and older. HGS was assessed using a handheld Smedley's Hand Dynamometer with a cut-off of 19.5 kg for men and 12.5 kg for women. Bivariate analysis showed the weighted percentage distribution of weak HGS across respondent characteristics. Multivariate logistic regression assessed factors linked to weak HGS. The concentration curve and index (CCI) was used to determine the inequalities in the prevalence of weak HGS by wealth index scores. Wagstaff's decomposition approach was used to test the contribution of each explanatory variable to weak HGS. Around 9% of older adults in this study reported a weak HGS. It was significantly higher among those aged 80 or older (19.21%) and males (15.55%). Weak HGS was concentrated among older adults from poor SES (CCI: 0.05, p < 0.001). A higher percentage of wealth-based inequality in weak HGS was explained by being underweight (38.83%), belonging to the richest wealth quintile (27.95%), and having a higher subjective social status (32.20%). Moreover, about 23.29% of the inequality in weak HGS was explained by Western region and 22.54% by female gender. Additionally, having a secondary level of education explained a higher percentage (22.09%) of inequality, followed by current working status (- 20.68%). Rural residence (13.08%), limitations in instrumental activities of daily living (IADL) (12.21%), and engagement in yoga-related activities (11.55%) explained a higher percentage of wealth-based inequalities. The findings provide evidence of significant SES-related inequalities in HGS and the contribution of various demographic, health, and behavioral factors to such inequality. As such, public health policies and programs focusing on reducing the burden of disability must consider the contribution of social and economic equity to the preservation of muscle strength among older adults.

Biological ageing and the risk of decreased handgrip strength among community-dwelling older adult Indians: a cross-sectional study

BACKGROUND

Evidence from the literature demonstrates that the risk of decreased handgrip strength is associated with various health issues, particularly in older persons. To make judgments regarding their general health condition that are well-informed for longevity, it is crucial to assess the risk level of decreased handgrip strength among community-dwelling older adult Indians. However, no study has examined the relationship between biological aging and the risk of decreased handgrip strength in Indian men and women aged 60 and older. The goal of the current study was to fill this gap in the literature.

METHODS

In this cross-sectional study, we included 31,464 (15,098 men and 16,366 women) community-dwelling older adult Indians aged 60 years and older using data from the Longitudinal Aging Study in India (LASI). The LASI is the world's most extensive and India's first multidisciplinary, internationally harmonized, longitudinal aging study. It has enrolled 72,250 individuals aged 45 and above across all 28 states and 8 union territories of India. Secondary analysis of biological ageing was performed by stratifying for age groups (60-64, 65-69, 70-74, 75-79, 80-84, and 85 + years) for both genders. The dominant right and nondominant left handgrip strength was assessed using the portable Smedley's Hand Dynamometer. All individuals had a dominant right hand. The adjusted logistic regression analysis assessed the association between biological ageing and the risk of decreased handgrip strength for both genders.

RESULTS

Compared to those between the ages of 60-64, those at age 65 and those aged 85 and above had 1-fold and 12-fold odds of decreasing handgrip strength, respectively. Men 85 years or older had a 12-fold higher chance than women in the same age group of having decreased handgrip strength.

CONCLUSIONS

The results indicate that community-dwelling older adult Indians aged 65 years and older are significantly associated with a higher risk of decreased handgrip strength, especially among older men. The results of this study can help assess and implement handgrip strength measurement in medicine for older Indians as part of regular admission assessment, particularly for older men.

Measures of attributes of locomotor capacity in older people: a systematic literature review following the COSMIN methodology

BACKGROUND

Locomotor capacity (LC) is an important domain of intrinsic capacity and key determinant of functional ability and well-being in older age. The United Nations Decade of Healthy Ageing (2021-2030) calls for strengthening data and research on healthy ageing, including the measurement of older persons' LC. To advance the measurement and monitoring of LC, there is pressing need to identify valid and reliable measures.

OBJECTIVE

To identify all the available tools that were validated for measurement of LC or of its specific attributes in older people and to assess the methodological quality of the studies and measurement properties of the tools.

DESIGN

Systematic review.

SETTING

Anywhere (Community-dwelling; long-term care facility; etc.).

SUBJECTS

Older people.

METHODS

We used highly sensitive search strategies to search the following databases: Medline, Embase, Scopus, CINAHL and PsycINFO. The study was conducted following the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) methodology for systematic review of outcome measurement instruments.

RESULTS

A total of 125 studies were included, which assessed tools for balance (n = 84), muscle power (n = 12), muscle strength (n = 32, including four studies about tools for balance and muscle power) and endurance (n = 1). No studies on tools for muscle function, joint function, or locomotor capacity overall, were retrieved. We identified 69 clinician-report or objective assessment tools for balance, 30 for muscle strength, 12 for muscle power and 1 endurance assessment tool. The GRADE assessment of quality of evidence showed that only a few tools have high quality evidence for both sufficient validity and reliability: The Balance Evaluation Systems Test (BESTest), the Mini-Balance Evaluation Systems Test (Mini-BESTest), the Berg Balance Scale (BBS) and the Timed Up and Go (TUG) test.

CONCLUSIONS

A few tools with high quality evidence for sufficient validity and reliability are currently available for balance assessment in older people that may be recommended for use in clinical and research settings. Further validation studies are required for muscle strength, muscle power and endurance assessment tools.

Effects of personal and health characteristics on the intrinsic capacity of older adults in the community: a cross-sectional study using the healthy aging framework

BACKGROUND

Intrinsic capacity (IC) can better reflect the physical functioning of older adults. However, few studies have been able to systematically and thoroughly examine its influencing factors and provide limited evidence for the improvement of intrinsic capacity. The objective of this study was to provide a comprehensive description of the overall decline in intrinsic capacity among older persons in the community. Additionally, the study aimed to analyze the composition of the five domains of reduction, compare the rate of decline among older adults and investigate the factors that influence this decline.

METHODS

This was a cross-sectional study conducted in the Chinese community. The self-designed general characteristics questionnaire was created based on the healthy aging framework and a systematic review. Intrinsic capacity was assessed with the Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS-15), Community Health Record Management System (CHRMS), Mini Nutritional Assessment Brief Form (MNA-SF), and Short Physical Performance Battery (SPPB). The influencing factors of intrinsic capacity were investigated using stepwise logistic regression.

RESULTS

A total of 968 older adults with a mean age of 71.00 (68.00, 76.75) were examined, and 704 older adults (72.7%) showed a decline in intrinsic capacity. There was a decline in at least one domain in 39.3% of older adults, with reductions in each domain ranging from 5.3% (psychological) to 52.4% (sensory). The study examined the composition of domains that experienced a decline in intrinsic capacity. It was found that a combination of sensory and locomotor domains showed the most significant decrease in 44.5% (n = 106) of individuals who experienced a decline in the two domains. Furthermore, a combination of sensory, cognitive, and locomotor domains exhibited a significant decrease in 51.3% (n = 44) of individuals who experienced a reduction in three domains. Lastly, a combination of sensory, vitality, cognitive, and locomotor domains showed the most significant decline in four domains, accounting for 60.0% (n = 15) of the population. Older adults had a higher risk of intrinsic capacity decline if they were older (95% CI:1.158-2.310), had lower education, lived alone (95% CI: 1.133-3.216), smoked (95% CI: 1.163-3.251), high Charlson Comorbidity Index (95% CI: 1.243-1.807) scores, did not regular exercise (95% CI:1.150-3.084), with lower handgrip strength (95% CI: 0.945-0.982).

CONCLUSIONS

We found a relatively high prevalence of intrinsic capacity; more attention should be paid to older adults who are older, less educated, live alone, and have more comorbidities. It is imperative to prioritize a healthy lifestyle among older persons who exhibit smoking habits, lack regular exercise, and possess inadequate handgrip strength.

Determinants of handgrip strength at age 2 years in children born moderate and late preterm and associations with neurodevelopmental outcomes

BACKGROUND

Handgrip strength (HGS) indicates current and future health. Although preterm infants have an increased risk of poor grip strength in later life, its determinants and relationship with neurodevelopment are not well understood.

AIMS

To determine HGS in children born preterm and explore the relationship of HGS with demography, anthropometry, nutritional factors, and neurodevelopmental outcomes.

STUDY DESIGN

A prospective cohort study of moderate-late preterm babies enrolled in a randomised trial of nutritional support strategies, the DIAMOND trial.

SUBJECTS

A total of 116 children born between 32 and 35 weeks' gestation, whose HGS was measured at 2 years' corrected age.

OUTCOME MEASURES

HGS was measured using a dynamometer, and neurodevelopment was assessed using the Bayley Scales of Infant Development-III. Anthropometry and body composition were assessed at birth, discharge, and at 4 months' and 2 years' corrected age. Information on demographics and breastfeeding practices, including type of milk at discharge and duration of exclusive breastfeeding, was collected using questionnaires.

RESULTS

The mean (standard deviation) HGS was 2.26 (1.07) kg. The Bayley scores were < 85 (-1 standard deviation) in 6 %, 20 %, and 1 % for the cognitive, language, and motor scales, respectively. Multiple regression analysis revealed that HGS was positively associated with language and motor scores (p < .05) after adjusting for confounding factors. HGS was not associated with sex, anthropometry, body composition, or breastfeeding practices. Maternal education was independently associated with HGS (p < .01).

CONCLUSIONS

HGS at age 2 years in children born moderate-late preterm is associated with language and motor development and maternal education level.

Measurements of Intrinsic Capacity in Older Adults: A Scoping Review and Quality Assessment

OBJECTIVES

This review summarizes the measurements of intrinsic capacity in 5 domains across different studies and evaluates the quality of research papers.

DESIGN

Scoping review of papers written in English and Chinese published in peer-reviewed journals.

SETTING AND PARTICIPANTS

The intrinsic capacity of older adults was assessed using the multidomain structure (Cognition, Locomotion, Psychological, Sensory and Vitality) proposed by the World Health Organization.

METHODS

We searched PubMed, MEDLINE, and Web of Science for papers in English, and CNKI, CBM for papers written in Chinese published until September 13, 2022. Both cross-sectional and cohort studies of multidomain measurements of intrinsic capacity were included. Three independent reviewers appraised the quality of studies, and Cohen's kappa was calculated to determine interrater reliability. Data were listed by author, year, setting, country, age range and number of participants, measurement and calculation of intrinsic capacity, and data acquisition method.

RESULTS

We included 53 studies. Twenty-one studies were of high quality, 31 studies were of moderate quality, and 1 study was of low quality. Measurements of intrinsic capacity and derivation of the summative index score were heterogeneous. Intrinsic capacity was usually assessed in 4 or 5 domains. Sensory was the most frequently overlooked domain or subdivided into vision and hearing in some studies. Indicators of vitality were the most heterogeneous. We also found consistency in heterogeneous measurements. The most common measurements of cognition, locomotion, and psychological capacity were the Mini-Mental State Examination, Short Physical Performance Battery, and Geriatric Depression Scale respectively. Self-reported questionnaires were commonly adopted in sensory domain. The Mini-Nutritional Assessment and grip strength were the most measured indicators of vitality.

CONCLUSIONS AND IMPLICATIONS

The focus on capacity and disease should be balanced to better promote healthy aging in older adults. Heterogeneity of intrinsic capacity measurements underscores the need for consensus about standardized measurements and calculation procedures.

Handgrip strength in older adults from Antioquia-Colombia and comparison of cutoff points for dynapenia

Handgrip strength is a predictor of functional impairment and presence of morbimortality in older adults. However, appropriate reference values and cutoff points are required for its optimal use. This study describes handgrip characteristics in the older adult population of Antioquia-Colombia and compares the dynapenia handgrip cutoffs proposed for Colombians with international criteria. A cross-sectional study including 1592 older adults was done. Dynapenia prevalence by handgrip was analyzed using the following cutoffs: European Consensus of Sarcopenia (2018), Asian Working Group for Sarcopenia (2019), Chilean (2018), and Colombian (2019). Handgrip strength significantly decreased with aging, showing a positive and strong association with functional and health parameters. The highest prevalence of dynapenia was found with the Asian Consensus cutoffs (26.1%) and the lowest with the Colombian cutoffs (0.8%). Low agreement was found between the Colombian cutoffs with the European Consensus (kappa = 0.059; p < 0.001), the Asian Consensus (kappa = 0.039; p < 0.001) and the Chilean proposal (kappa = 0.053; p < 0.001). Dynapenia using the Chilean, European, and Asian cutoffs was associated with physical inactivity, presence of multimorbidity, slow gait speed, nutritional risk, and low calf circumference. Meanwhile, the Colombian cutoffs was only associated with slow gait speed and low calf circumference. The handgrip cutoffs proposed for Colombians seems to underestimate the dynapenia prevalence in older people from Antioquia. Furthermore, these cutoff points did not show associations with relevant functional and health parameters. The handgrip cutoffs proposed for Colombians should be used with caution.

Approaching person-centered clinical practice: A cluster analysis of older inpatients utilizing the measurements of intrinsic capacity

Background

Maintaining the intrinsic capacity (IC) of older inpatients is a novel view in providing person-centered treatments in clinical practice. Uncertainty remains regarding the primary nature of IC among older hospitalized patients.

Objectives

We aimed to understand the status of IC among older inpatients by a cluster analysis based on IC measurements.

Methods

This is a cross-sectional study conducted in the geriatric department of Beijing Hospital in China. Older inpatients who were older than 60 years and who underwent comprehensive geriatric assessments were included. The inpatients were classified into subgroups based on 13 measurements of IC according to unsupervised methods (K-means cluster analysis and t-SNE). Subgroup differences were investigated for domains of IC, age, sex, frailty, activities of daily living, and falls.

Results

A total of 909 inpatients with a mean age of 76.6 years were included. Almost 98% of the inpatients showed IC impairment. Locomotion impairment was the most prevalent problem (91.1%), followed by sensory impairment (61.4%), psychological impairment (57.3%), cognition decline (30.7%), and vitality problem (29.2%). A total of five clusters were obtained by classification: Cluster 1 (56.6% of the participants) showed high IC with fair impairment of locomotion and vision; clusters 2 and 3 (37.8 % of the participants) had additional impairment of sleep in the psychological domain; clusters 4 and 5 (5.6% of the participants) represented a severe loss of all the IC domains; and clusters 1-5 showed a gradual decline in the IC score and were significantly associated with increased age, frailty, decreased activities of daily living, and falls. Significant correlations among the domains were observed; the locomotion domain showed the strongest links to the others in network analysis.

Conclusions

Great declines in IC and disparities between IC domains were found in older inpatients. IC-based primary assessment and classification enabled us to identify the variation of functional abilities among the older inpatients, which is pivotal for designing integrated treatment or care models in clinical practice.

Association between changes in handgrip strength and depression in Korean adults: a longitudinal panel study

Depression in older adults is a global socioeconomic burden. Identifying factors, such as physical activity or exercise that can help prevent depression is important. We aimed to investigate the relationship between changes in handgrip strength and the presence of depression using longitudinal, nationwide data of older Korean adults. Data from the Korean Longitudinal Study of Aging were used in this study. A total of 6783 participants who had undergone a handgrip strength test and completed the short-form Center for Epidemiologic Studies Depression Scale (CESD-10-D) questionnaire from 2006 to 2018 were included. General estimating equations were used to assess the temporal effect of the changes in handgrip strength on depression. A decrease in handgrip strength was associated with high CESD-10-D scores (β = 0.1889 in men, β = 0.1552 in women). As a continuous variable, handgrip strength was negatively correlated with CESD-10-D scores(β = - 0.0166 in men, β = - 0.0196 in women). Changes in the handgrip strength were associated with depressive symptoms in our longitudinal study. Those who experienced a decrease in handgrip strength had severe depressive symptoms compared to those with unchanged or increased handgrip strength. These findings can be used to guide general health policies for the prevention of depression.

Intrinsic Capacity Declines with Elevated Homocysteine in Community-Dwelling Chinese Older Adults

Purpose

Intrinsic capacity (IC) reflects the overall health status of older adults and has great public health significance. But few studies described the related biomarkers for IC. The aim of this study was to investigate the association between homocysteine (Hcy) and IC in older adults.

Participants and Methods

This cross-sectional study included 1927 community-dwelling Chinese older adults aged 60–98 years from May 2020 to December 2020. Data were collected through interviews, physical examinations, and laboratory tests. IC involved five domains of cognition, locomotion, sensory, vitality, and psychology evaluated by the Mini-cog scale, 4-m walk test, self-reported visual and hearing conditions, MNA-SF scale, and GDS-4 scale, respectively. The score of each domain dichotomized as 0 (normal) and 1 (impaired) was added together to an IC total score. Low IC was defined as a score of 3–5, and high IC as 0–2. Hcy was measured by a two-reagent enzymatic assay. A restricted cubic spline regression model was used to explore the non-linear relationship between Hcy and low IC.

Results

Hcy was higher in the low IC group than in the high IC group. Restricted cubic spline analysis revealed a J-shaped nonlinear association between Hcy and low IC. The risk of IC decline was slowly decreased until 8.53 µmol/L of Hcy (OR=0.753, 95% CI=0.520–1.091, P=0.132), and increased with elevations of per 5 µmol/L Hcy afterwards (OR=1.176, 95% CI=1.059–1.327, P=0.005). Among the five domains of IC, Hcy had ORs of 1.116 (1.009–1.247) for cognition impairment, 1.167 (1.055–1.305) for vitality, and 1.160 (1.034–1.303) for psychology per 5 µmol/L increase in Hcy above the change point. Additional sensitivity analysis also demonstrated the nonlinear association between Hcy and low IC.

Conclusion

Hcy had a J-shaped association with low IC. Higher Hcy (Hcy ≥8.53µmol/L) might provide clinical implications for early identifying the risk of low IC.

Sit to stand muscle power reference values and their association with adverse events in Colombian older adults

Recently, a valid method to assess lower-body muscle power based on a sit-to-stand field test (STS) has been published. Our study aimed to describe lower-body muscle power in older individuals aged ≥ 60 years and examine the relationship of muscle weakness with adverse events according to gender- and age-specific muscle weakness cut-off points. A total of 3689 Colombian older adults (57.6% women, age 69.1 ± 6.9 years) from the 2015 Survey on Health, Well-Being, and Aging in Latin America and the Caribbean (SABE) participated in this study. Lower-body muscle power normalized to body mass was estimated by the five-repetitions STS test. Anthropometric, physical performance and clinical characteristics were collected. Age-specific percentiles using the LMS method, cut-off points and association with adverse events were calculated. Lower-body muscle power was greater in men than among women (2.2 ± 0.7 vs. 1.6 ± 0.5 W·kg⁻¹, respectively; p < 0.001) at all ages. Muscle power ranked in the 50th percentile between 2.38 and 1.30 W·kg⁻¹ in men, whereas women ranked between 1.79 and 1.21 W·kg⁻¹. According to the cut-off points, lower-limb muscle power < 1 standard deviation  in men was associated with having dynapenia, poor gait speed, cognitive impairment and mental, visual, hearing and memory problems. While, women were associated with having sarcopenia, dynapenia, poor gait speed, cognitive impairment, mental, hearing and memory problems, dementia and hospitalizations of > 24 h in the last year. Overall, participants with poor lower-limb muscle power had a significantly higher risk of adverse events [in men: odds ratio (OR) = 1.51, 95% confidence interval (CI) = 1.19–1.91, p < 0.001; in women: OR = 1.52, 95% CI = 1.27–1.87, p = 0.001] than their stronger counterparts. This study is the first to describe lower-limb muscle power values and cut-off points among a nationally representative sample of Colombian older adults. In men, 7 of the 14 adverse events studied were associated with lower muscle strength, whereas in women, it was 9 of the 14 adverse events.

Exploring the conceptual framework and measurement model of intrinsic capacity defined by the World Health Organization: A scoping review

WHO has defined intrinsic capacity (IC) as the composite of all physical and mental capacities of an individual covering five subdomains: cognition, locomotion, sensory, vitality, and psychological. Despite this well accepted definition, the conceptual and measurement model of IC remains unclear, which hampers a standardized operationalization of the construct. We performed a scoping review to give a comprehensive overview of the extent to which the current literature of IC addresses and assumes the conceptual framework and measurement model of IC as reflective or formative. For inclusion, we considered all types of articles that were published in peer-reviewed journals except for protocol articles. A systematic search of 6 databases from different disciplines led to the inclusion of 31 papers. We found inconsistency and gaps in the descriptions of IC. Most of the papers did not define the measurement model. In the conceptual background and validation articles, we identified descriptions of both reflective and formative measurement models while in empirical studies applying IC measurements the underlying assumptions remained mainly unclear. Defining a measurement model is not merely a theoretical matter but influences the operationalization and validation processes of the construct. This study raised questions about the most fundamental features of the IC construct and discusses whether IC should be considered as an underlying latent trait of all capacities (reflective construct) or an aggregate summary measure of the subdomain capacities (formative construct).

Combined effects of handgrip strength and sensory impairment on the prevalence of cognitive impairment among older adults in Korea

Older adults commonly experience concurrent lower handgrip strength and sensory impairment. However, previous studies have analyzed the individual effects of either handgrip strength or sensory impairment on cognitive impairment. To address this gap, this study investigated the combined effects of handgrip strength and sensory impairment on cognitive impairment among older adults. In total, 2930 participants aged 65 and older were analyzed using 2014–2018 data from the Korean Longitudinal Study of Aging. Participants underwent assessments of handgrip strength (grip dynamometer), sensory impairment (self-reported responses), and cognitive impairment (Korean version of the Mini-Mental State Examination). Low handgrip strength, compared to normal handgrip strength, was associated with cognitive impairment. In participants with low handgrip strength, vision and hearing impairment were associated with cognitive impairment (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.06–1.75; OR 2.58, 95% CI 1.77–3.78, respectively) compared to those with normal handgrip strength. Participants with low handgrip strength and dual sensory impairment had the highest OR for cognitive impairment (OR 3.73, 95% CI 2.65–5.25). Due to the strong association of low handgrip strength and dual sensory impairment with cognitive impairment, people living with low handgrip strength and dual sensory impairment should be classified as a high-risk group for cognitive impairment and should be prioritized for interventions.