Korean Longitudinal Study Research Articles

Systematic identification and quantification of factors and their interactions with age, sex, and panel wave influencing cognitive function in Korean older adults

BackgroundCognitive decline in older adults is influenced by diverse factors, and degrees of influence of these factors may vary depending on sex, age cohorts, and passage of time. Moreover, these factors differ in their responsiveness to general interventions. Thus, identifying these factors including their interactions with age, sex, and panel wave and conducting a systematic quantification of their influences on cognitive function are both necessary for developing efficient intervention strategies.MethodsTo identify the influencing factors and their interactions, we applied a systematic stepwise variable selection using 2,535 community-dwelling older adults who participated in the Korean Longitudinal Study of Aging from Wave 5 (2014) to Wave 8 (2020). These factors were subsequently grouped based on their modifiability to investigate group-wise influences on cognitive function. For handling the longitudinal data, a generalized least squares method was used, and the degrees of influence of these factors were measured using the delta R2.ResultsTwelve variables had significant main effects on cognitive function in older adults. Among these variables, age interacted with sex, regular exercise, and marital status. Sex interacted with regular exercise, education level, and depressive symptoms. Wave number interacted with depressive symptoms and social activity. In addition, the group-wise delta R2 values were found to be 10.9, 6.3, and 5.9% in the difficult-to-modify, modifiable, and non-modifiable factor groups, respectively. Afterwards, we provided the delta R2 for each sub-population divided by the levels of age, sex, and wave number to examine how these factors changed the influences.ConclusionBased on the interaction and quantification results, we elucidated the characteristics of the influencing factors and their degrees of influence, and we suggest grouping factors based on their modifiability to systematically prevent cognitive decline in older adults.

Depressive intensity, duration, and their associations with cognitive decline: a population-based study in Korea.

Existing epidemiological studies have ignored the effect of depressive duration on cognitive decline despite the presence of biological cues and understudied the depression-cognition association in Asian countries in the context of increasing cognitive burden worldwide. We aimed to comprehensively characterize the effects of depressive duration and intensity on cognitive decline at the population level. A total of 6406 individuals from the Korean Longitudinal Study of Aging (KLoSA) from 2010 to 2018 were included to generate four datasets with durations of 2, 4, 6, and 8years. Depressive intensity was categorized as no, mild, and major depression according to the Center for Epidemiological Studies Depression scale (CES-D10), and duration was measured by the span of consecutive interviews. Cognitive function was assessed using the Korean Mini-Mental Status Examination (K-MMSE). Multiple linear regressions and meta-regressions were used to estimate the effects of depressive intensity and duration on global cognition and seven cognitive subdomains. Stratified analyses were performed to explore effect differences between subpopulations of different sexes and ages. The potential bias in the effect of depressive intensity on cognitive decline when ignoring duration was also explored. On average, a 1-year longer duration decreased the global cognitive scores by 0.44 (95% CI 0.36, 0.51) across intensities and major depression decreased the scores by an additional 0.82 (95% CI 0.59, 1.04) points than mild depression across durations. Similar trends held for seven cognitive subdomains except for visual construction. Older adults suffered more cognitive decline from major depression than middle-aged adults did. More severe and longer-duration depression lead to greater cognitive decline. Ignoring depressive duration can lead to an overestimated effect of depressive intensity on cognitive decline. The depressive effects and susceptible populations clarified in our study have important implications for the preservation of cognitive health in Asian region.

Association Between Geriatric Oral Health Assessment Index and Cardio-cerebrovascular Disease in Korean Older Adults.

This study examined the association between oral health-related quality of life (OHRQoL), as assessed by the Geriatric Oral Health Assessment Index (GOHAI), and cardiovascular disease (CVD) outcomes among Korean older adults. Data from 5413 participants in the Korean Longitudinal Study of Aging were analyzed. GOHAI scores were categorized as either "poor" (<40) or "not poor" (≥40). Generalized estimating equation models were used to assess the relationship between GOHAI scores and CVD prevalence, with analyses stratified by sex. Poor GOHAI score was significantly associated with elevated odds of CVD (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.07 to 1.19; p<0.001). This association was stronger in women (OR, 1.36) compared to men (OR, 1.12). Poor oral health is indicative of systemic inflammation and age-related vulnerabilities, underscoring the utility of the GOHAI as an instrument for early identification of CVD risk. Poor oral health, as measured by the GOHAI, is associated with an increased risk of CVD among older adults, especially women. These findings support the use of the GOHAI as a cost-effective screening tool for the early assessment of CVD risk. Further research is warranted to explore inflammatory biomarkers and sex-specific mechanisms that could inform targeted interventions.

Effect of healthy lifestyle score trajectory on all-cause mortality in the late middle-aged and older population: Finding from 17-year retrospective cohort study.

Recently, the World Health Organization has emphasized the importance of a healthy lifestyle in reducing severe illnesses and premature mortality. To evaluate this, the Healthy Lifestyle Score (HLS), which focuses on health protecting behaviors (e.g., smoking, alcohol consumption, physical activity, body mass index), is widely used. However, as HLS may fluctuate over time, there is increasing focus on monitoring HLS trends. Accordingly, this study aims to track HLS trajectories (HLST) and examine their association with mortality among middle-aged and older Koreans. After excluding missing values, data from 6249 participants were analyzed using the group-based trajectory model (GBTM) to classify HLST, based on the first to fourth waves of the Korean Longitudinal Study of Aging (KLoSA). The chi-square test and Cox proportional hazards model were employed to examine the association between HLST and all-cause mortality over a 10-year follow-up period (December 31, 2012, to December 31, 2022; 3650 days). Three HLST groups were identified in the GBTM analysis. These were the Poor HLST (17.8 %), Average HLST (42.9 %), and Good HLST (39.4 %) groups. Compared to the good HLST, the poor HLST had higher mortality at 1 year (hazard ratio [HR]: 1.98, p: 0.029), 3 years (HR: 1.78, p: 0.001), 5 years (HR: 1.52, p: 0.002), 7 years (HR: 1.39, p: 0.002), and 10 years (HR: 1.40, p: 0.000). Furthermore, stratified analysis by sex, age, marital status and residential region showed that male, ≥65 years, single and urban area groups had a strong association between HLST and all-cause mortality. The findings of this study underscore the necessity of policies and institutional measures grounded in community networks to mitigate the risk of all-cause mortality among vulnerable groups with persistently poor HLST.

The unintended effects of a large minimum wage increase on health: Evidence from South Korea.

The 2018 minimum wage increase in South Korea was a major policy change that impacted employment and labour productivity, but its effects on health have not yet been explored. The minimum wage was increased by 16.4% in January 2018, marking the largest increase over two decades and a substantial increase by international standards. While this policy change was a promise of the then-new government, the magnitude of its increase was unexpected. Using a difference-in-differences design with data from the 2016 and 2018 Korean Longitudinal Study on Aging, this study focuses on individuals targeted by the minimum wage policy, particularly older adults earning the minimum wage. Unexpectedly, our results indicate a statistically significant decrease in cognitive function within the targeted group, following the minimum wage hike. However, we did not observe any significant changes in self-reported health. Importantly, for the period 2014 and 2016, when the minimum wage increase was relatively modest, we found positive effects on cognitive health and no negative effects on self-reported health, suggesting that negative effects on cognition emerged only with the large minimum wage increase in 2018. These perhaps unexpected findings may be explained by a significant reduction in the working hours of the targeted group.

Retrospective observational study of the association between changes in physical activity and frailty in middle-aged and older adults: evidence from the Korean Longitudinal Study of Aging (2006–2022)

ObjectivesThis study aimed to investigate the relationship between changes in physical activity and frailty among middle-aged and older adults in Korea, using panel data from the 2006–2022 Korean Longitudinal Study...

The relationship between trajectories of intrinsic capacity and differences in the risk of functional ability decline in community-dwelling older adults: A socio-ecological approach.

Functional ability (FA), a key determinant of healthy aging, is determined by intrinsic capacity (IC), environmental factors, and their interactions. IC is a composite of physical and mental capacities that undergo constant change. Therefore, understanding the factors that influence IC requires a multi-level analysis of individuals to optimize its trajectory. Individuals aged ≥ 65 were included in the Korean Longitudinal Study of Aging (2012-2020). Impaired IC (IIC) scores were tracked over eight years using latent class growth modeling to classify trajectory patterns. Determinants were identified through multinomial logistic regression. The relationship between IIC trajectory and FA decline was assessed using Kaplan-Meier analysis and the Cox proportional hazards model. Of the 7486 subjects, 2268 (mean age 72.26 [SD 5.31] years; female 56.4 %) were included after excluding those who were underage, had lost independence, or were missing baseline data. The IIC trajectories were categorized into four classes: low-persistent (Class 1, 48.46 %); low-increasing (Class 2, 17.46 %); high-decreasing (Class 3, 20.37 %); and high-stable (Class 4, 13.71 %). Over a mean follow-up of 7.21 years, 536 individuals experienced a decline in FA. After adjusting for confounders, the hazard ratios (HRs) were 1.95 (95 % CI 1.51-2.50) for class 2, 1.93 (1.50-2.46) for class 3, and 3.41 (2.64-4.39) for class 4 compared to class 1. Additionally, age, gender, marital status, employment, social participation, and living status had overlapping effects on both IC and FA. Understanding the heterogeneity of IC, combined with multidomain interventions, can enable FA maintenance and promote healthy aging.

Marital satisfaction and its impact on frailty in Korean older adults: a longitudinal analysis

AbstractBackgroundDespite a wealth of literature on marital dissatisfaction and adverse health outcomes, little is known about the relationship between marital dissatisfaction and frailty in older adults.MethodsThis longitudinal study utilised the data of 11 174 individuals who participated in the biennial Korean Longitudinal Study of Ageing survey from 2006 to 2020 and were aged ≥45 during the initial wave. Frailty was measured using a frailty instrument, which utilised exhaustion, social isolation, and handgrip strength weakness. Marital dissatisfaction was defined as a decrease in marital satisfaction of at least 10 points compared to the previous wave. Lagged generalised estimating equation analyses were conducted to investigate the impact of marital dissatisfaction on frailty.ResultsFrail participants were more likely to be older, female, have higher rates of depression, lower socioeconomic status (as indicated by lower household income and education level), and with more comorbidities. Multivariate logistic model analysis revealed that individuals who became dissatisfied with their marriage had higher odds ratios for being frail than those who did not, and this trend was true in women and individuals with a low socioeconomic status. However, the development of frailty was not significantly associated with dissatisfaction with marriage.ConclusionThe findings of this study suggest that marital dissatisfaction is a robust predictor of frailty in older adults. Efforts aimed at addressing marital dissatisfaction have the potential to prevent frailty in women and individuals of low socioeconomic status.

ADULT CHILDREN‘S SINGLEHOOD AND AGING PARENTS’ PSYCHOLOGICAL WELL-BEING IN SOUTH KOREA

Abstract Guided by a life course perspective, this study aims to examine the linkages between the marital status of adult children as an indicator of the transition to adulthood and their parents’ psychological well-being, considering how parental socioeconomic resources play a role in this association. We conducted a series of regression models using data from the 2018 Korean Longitudinal Study of Ageing (KLOSA, n=3112 aging parents who had at least one child over 35 years old). Consistent with the exposure model, having an unmarried son was associated with poorer parental psychological well-being, irrespective of parental income and education. However, parental education partially explained the association between daughter’s marital status and parental psychological well-being, suggesting that parental well-being regarding adult children’s marital status may depend on child’s gender and parental education level. This study has implications for the intergenerational relationships in collectivist and patrilineal Eastern cultural context. Aging parents’ psychological well-being ties to their adult children’s marital status based on the social norm regarding the transition to adulthood, and particularly sons’ marital status than that of daughters’. Also, aging parents may have different views on daughter’s marital status depending on their educational attainment. In sum, based on the concept of ‘linked-lives’ and stress process model, this study provides an extended understanding of intergenerational relations in later life in Korea. Clinicians and family professionals should consider well-being in old age associated with adult children’s life transitions and gender in the cultural context.

Investigating the influence of working status changes on physical activity and non-communicable diseases in Korean middle-aged and older adults: insights from a longitudinal panel study

BackgroundNon-communicable diseases (NCDs) are a major global health challenge and occupational status is a critical determinant influencing NCD development, yet many cross-sectional studies have only linked current occupational status with specific diseases, overlooking broader temporal factors. The primary aim of the present study was to comprehensively elucidate the intricate interplay between alterations in working status, NCDs, and physical activity (PA) among Korean middle-aged and older adults, employing a longitudinal panel study design.MethodsThis study utilized longitudinal data from the Korean Longitudinal Study of Aging, covering the period from 2006 to 2020, with a median follow-up duration of 10 years. (n = 5101 participants aged 45 years and older). Changes in working status were categorized, focusing on (1) yes–yes (e.g., indicative of sustained employment), (2) yes–no (e.g., denoting a transition from employment to non-employment), (3) no–yes (e.g., representing a shift from non-employment to employment), and (4) no–no (reflecting a continual non-employment status). PA was defined as the total minutes of moderate-to-vigorous PA per week and categorized into two groups: <150 min/week and ≥ 150 min/week. Confounding factors included age, gender, marital status, education level, and body mass index. Relative risk ratios (RRR) with 95% confidence intervals (CI) were calculated using random-effect multinomial logistic regression.ResultsIndividuals who were currently employed (adjusted RRR = 0.688, 95% CI = 0.656–0.722, p < 0.001) or who transitioned to employment (adjusted RRR = 0.755, 95% CI = 0.707–0.807, p < 0.001) had a reduced risk of physical inactivity. However, employed individuals had an increased risk of cardiovascular diseases (yes-yes: adjusted RRR = 1.653, 95% CI = 1.547–1.766, p < 0.001; no-yes: adjusted RRR = 1.168, 95% CI = 1.100–1.240, p < 0.001) and diabetes (yes-yes: adjusted RRR = 1.535, 95% CI = 1.464–1.610, p < 0.001; no-yes: adjusted RRR = 1.124, 95% CI = 1.078–1.173, p < 0.001). Additionally, current workers exhibited higher risks of cancer (yes-yes: adjusted RRR = 1.871, 95% CI = 1.721–2.035, p < 0.001; no-yes: adjusted RRR = 1.089, 95% CI = 1.018–1.166, p = 0.014) and chronic respiratory diseases (yes-yes: adjusted RRR = 1.467, 95% CI = 1.307–1.648, p < 0.001; no-yes: adjusted RRR = 1.121, 95% CI = 1.011–1.242, p = 0.029).ConclusionThis longitudinal study revealed that individuals engaged in or transitioning to employment displayed a reduced likelihood of regular PA. Moreover, those with work history, transitioning, or consistently working, exhibited increased vulnerability to all NCDs compared to those without work experience.

Factors Affecting the Subjective Health Status of Middle-Aged Retirees in Korea

Background: Countries that are becoming aging societies are struggling to establish financial support policies due to their increasing numbers of retired people. In particular, the increase in middle-aged retirees has been reported as unusual and influenced by various factors. This study aimed to identify the subjective health conditions of middle-aged retirees and explore the factors that help provide basic data for developing health-related programs for them. Methods: This cross-sectional study was conducted among 7,893 people who participated in the 6th Korean Longitudinal Study of Aging in 2016. Among them, the data of 315 participants were analyzed. A theoretical framework guided the use of multiple regression analysis to examine the factors related to the subjective health status of middle-aged retirees. Results: The significant factors influencing the subjective health status were socioeconomic status (middle/high: β=.14, P=.005), number of chronic diseases (β=-.11, P=.035; above 2: β=-.38, P&lt;.001), depression (β = -.17, P&lt;.001), and retirement satisfaction (β=.32, P&lt;.001). Conclusion: This study can help policymakers create effective retirement programs for middle-aged individuals and re-socialize them by enhancing physical and psychological support.

The Relationship Between Work and Depressive Symptoms in Older Adults: The Moderating Effect of Income, Subjective Socioeconomic Status, and Social Participation

ABSTRACT Objectives We examined the moderating effects of household income, subjective socioeconomic status (SES), social contact, and social engagement on the work-depressive symptoms relationship. Methods We analyzed data from 5,216 adults aged 60 and older from six waves (2008–2018) of the Korean Longitudinal Study of Ageing (KLoSA). Results Two-level mixed-effects models showed that within-individual variation in work status was negatively associated with depressive symptoms. The relationship between work and depressive symptoms was stronger for older adults with low household income than for those with the average household income and was not significant for those with high household income. Moreover, the work-depressive symptoms relationship was stronger among older adults with low levels of subjective SES and social engagement and fewer social contacts compared with those with average or high levels of subjective SES and social engagement and more social contacts. Conclusions The greater impact of work on depressive symptoms in older adults with limited financial and social resources highlights the importance of addressing these deficits to improve mental health. Clinical Implications Clinicians should consider that the effect of work on depression varies depending on income, subjective SES, and social participation. Addressing financial hardship and promoting social participation are important for preventing depression in older adults.

Exploration of Neuroanatomical Characteristics Relating to Progression from Preclinical to Prodromal Alzheimer's Disease

AbstractBackgroundTo investigate the neuroanatomical characteristics at the whole‐brain level associated with progression from amyloid‐positive preclinical to prodromal Alzheimer’s disease (AD) in relation to amyloid deposition and regional atrophy.MethodWe included 45 participants with amyloid‐positive preclinical AD and 135 participants with prodromal AD matched 1:3 by age, sex, and education, from participants in the Korean Longitudinal Study on Cognitive Aging and Dementia and visitors to the dementia clinic of Seoul National University Bundang Hospital. All participants underwent 18F‐florbetaben positron emission tomography and 3D structural T1‐weighted magnetic resonance imaging. We calculated the standardized uptake value ratios (SUVRs) and volumes in 80 regions of interest (ROIs) using the Desikan‐Killiany‐Tourville atlas and compared them between the preclinical and prodromal AD groups. We used the least absolute selection and shrinkage operator (LASSO) logistic regression model to identify ROIs associated with prodromal AD in relation to amyloid deposition, regional atrophy, and their interaction.ResultAlthough global SUVR did not differ between the amyloid‐positive preclinical and prodromal AD groups, the prodromal AD group showed a higher SUVR in the superior parietal cortex, right precuneus cortex, and right supramarginal gyrus. Regional volume differences between the two groups were observed in the overall cortex and subcortical areas, except in the occipital lobe, and the LASSO logistic regression model showed significant associations between prodromal AD and atrophy in the entorhinal cortex, inferior parietal cortex, both amygdalae, and left hippocampus. The mean SUVR in the right superior parietal cortex (beta coefficient = 0.0172) and its interaction with the regional volume (0.0672) were also selected in the LASSO model. The mean SUVR in the right superior parietal cortex was strongly associated with an increased risk of prodromal AD, particularly in participants with lower regional volume.ConclusionCompared with amyloid‐positive preclinical AD, patients with prodromal AD showed more regions with significant volume differences than amyloid deposition. Amyloid deposition in the right superior parietal cortex may play a significant role in the progression of prodromal AD, particularly in interaction with its reduced volume.

Analysis of the types of social activity participation of older adults living in the community and the health level and quality of life by types: Applying Latent Class Analysis

AbstractBackgroundParticipation in various social activities of elderly has a significant impact on overall health and quality of life, including physical and metal health. Therefore, in this study, we aim to analyze the types of social activity participation among community‐dwelling elderly and examine differences in characteristics, health status, and quality of life according to these types of participation of social activities. Thus, we purpose to utilize the findings of this study as a foundation basis for research aimed at promoting services and intervention related to social activities of elderly in community.MethodThis study utilized the 9th wave (2022) panel data from the Korean Longitudinal Study of Elderly Employment(KLoSA). Latent class analysis was utilized to explore types of social activities. To assess the goodness of fit of the latent model, χ² (Chi‐square) test, Akaike Information Criteria (AIC), Bayesian Information Criteria (BIC), Sample‐Size Adjusted Bayesian Information Criteria (SABIC) indices, and Lo‐Mendell‐Rubin adjusted Likelihood Ratio Test (LMR‐LRT) were employed. One‐way ANOVA was conducted to examine characteristics across different types.ResultThe study included a total of 6,057 elderly individuals aged 60 and above residing in the local community for analysis. The results demonstrate four distinct types of social activity participation among the elderly. These four groups were named based on the types of social activities they engaged in: “Religious and Social Activity Centered,” “Social and Leisure Activity Centered,” “Social Activity Centered,” and “Inactive.” The analysis of characteristics across these types showed statistically significant differences in demographic factors such as age, marital status, and religion. In terms of health‐related aspects, subjective health and overall quality of life indices exhibited statistically significant differences among the types.ConclusionSocial activities among the elderly were analyzed into four distinct types based on the activities they engaged in. The participation of elderly individuals in various social activities is considered a crucial indicator for improving health and quality of life. It is hoped that this study will serve as a foundational basis for developing services and intervention programs for elderly individuals in the community, aimed at facilitating their participation in diverse social activities.

Effect of Occupational Toxin Exposure on the risk of dementia; Results of the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD)

Effect of Occupational Toxin Exposure on the risk of dementia; Results of the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD)

Factors Influencing Perceived Health Status among Community-dwelling Elderly Individuals with Fear of Falling: An Analysis Based on Data from the Ninth Korean Longitudinal Study of Aging 2022

Factors Influencing Perceived Health Status among Community-dwelling Elderly Individuals with Fear of Falling: An Analysis Based on Data from the Ninth Korean Longitudinal Study of Aging 2022

Factors Affecting Oral Health-Related Quality of Life in Community-Dwelling Older Adults Living Alone: An Analysis of Data from the Ninth Korean Longitudinal Study of Aging

Purpose: This study aimed to comprehensively evaluate the factors influencing the oral health-related quality of life (OHRQoL) of community-dwelling older adults living alone, using data from the ninth Korean Longitudinal Study of Aging (KLoSA). Methods: A secondary analysis of the ninth KLoSA dataset from 2022 was conducted. The study sample comprised 1,038 community-dwelling older adults living alone. The dependent variable of this study was OHRQoL, while the independent variables included socio-demographic, oral health-related, general health-related, and health behavior-related characteristics. Factors influencing OHRQoL were assessed using a complex samples general linear model with the Bonferroni correction in IBM SPSS/Win 26.0. Results: The average OHRQoL score was 37.47±0.35 out of 60. The factors influencing the OHRQoL of community-dwelling older adults living alone included age (≥85 years) (t=-3.03, &lt;i&gt;p&lt;/i&gt;=.003), wearing dentures (t=-2.11, &lt;i&gt;p&lt;/i&gt;=.035), difficulty in daily activities due to vision impairment (t=-2.26, &lt;i&gt;p&lt;/i&gt;=.024), difficulty in daily activities due to hearing impairment (t=-2.21, &lt;i&gt;p&lt;/i&gt;=.028), and depression (t=-8.38, &lt;i&gt;p&lt;/i&gt;&lt;.001). Conclusion: Based on our findings, to improve the OHRQoL of community-dwelling older adults living alone, it is necessary to consider psychological factors, such as depression, when developing ongoing oral health-management programs aimed at improving OHRQoL. Additional considerations include effective management of dentures and addressing difficulties in daily activities due to vision and hearing impairments.

A Multivariable Prediction Model for Mild Cognitive Impairment and Dementia: Algorithm Development and Validation.

Mild cognitive impairment (MCI) poses significant challenges in early diagnosis and timely intervention. Underdiagnosis, coupled with the economic and social burden of dementia, necessitates more precise detection methods. Machine learning (ML) algorithms show promise in managing complex data for MCI and dementia prediction. This study assessed the predictive accuracy of ML models in identifying the onset of MCI and dementia using the Korean Longitudinal Study of Aging (KLoSA) dataset. This study used data from the KLoSA, a comprehensive biennial survey that tracks the demographic, health, and socioeconomic aspects of middle-aged and older Korean adults from 2018 to 2020. Among the 6171 initial households, 4975 eligible older adult participants aged 60 years or older were selected after excluding individuals based on age and missing data. The identification of MCI and dementia relied on self-reported diagnoses, with sociodemographic and health-related variables serving as key covariates. The dataset was categorized into training and test sets to predict MCI and dementia by using multiple models, including logistic regression, light gradient-boosting machine, XGBoost (extreme gradient boosting), CatBoost, random forest, gradient boosting, AdaBoost, support vector classifier, and k-nearest neighbors, and the training and test sets were used to evaluate predictive performance. The performance was assessed using the area under the receiver operating characteristic curve (AUC). Class imbalances were addressed via weights. Shapley additive explanation values were used to determine the contribution of each feature to the prediction rate. Among the 4975 participants, the best model for predicting MCI onset was random forest, with a median AUC of 0.6729 (IQR 0.3883-0.8152), followed by k-nearest neighbors with a median AUC of 0.5576 (IQR 0.4555-0.6761) and support vector classifier with a median AUC of 0.5067 (IQR 0.3755-0.6389). For dementia onset prediction, the best model was XGBoost, achieving a median AUC of 0.8185 (IQR 0.8085-0.8285), closely followed by light gradient-boosting machine with a median AUC of 0.8069 (IQR 0.7969-0.8169) and AdaBoost with a median AUC of 0.8007 (IQR 0.7907-0.8107). The Shapley values highlighted pain in everyday life, being widowed, living alone, exercising, and living with a partner as the strongest predictors of MCI. For dementia, the most predictive features were other contributing factors, education at the high school level, education at the middle school level, exercising, and monthly social engagement. ML algorithms, especially XGBoost, exhibited the potential for predicting MCI onset using KLoSA data. However, no model has demonstrated robust accuracy in predicting MCI and dementia. Sociodemographic and health-related factors are crucial for initiating cognitive conditions, emphasizing the need for multifaceted predictive models for early identification and intervention. These findings underscore the potential and limitations of ML in predicting cognitive impairment in community-dwelling older adults.

The impact of job fitness on depressive symptoms in Korean middle-aged and older population: a longitudinal study.

This study aimed to determine the impact of job fitness on depression and depressive symptoms in Korean middle-aged and older population. We collected data from the Korean Longitudinal Study of Aging (KLoSA), and performed a longitudinal analysis on 3,185 individuals with jobs at baseline. The dependent variable, depressive symptoms was measured by CES-D10 score, and the main variable of interest, job fitness was classified into nine groups according to job satisfaction and education level. To determine whether the estimate of depressive symptoms over the past week and depression changed over time, we applied the Generalized Estimating Equation (GEE) model. In the fully adjusted model, the impact of job fitness on depression and depressive symptoms was statistically significant. Compared to those with a suitable job level and a medium educational level, those with a large gap between job and educational levels were more likely to develop depression and depressive symptoms. It was also found that satisfaction with job content was a crucial factor affecting depression in the middle-aged and older adults. Our findings demonstrated that job fitness significantly influenced depression, even after accounting for the effect of job satisfaction caused by a mismatch in job-education fitness. Since work demands and responsibility are difficult to quantify or qualify, job-education fitness could serve as a valuable tool to predict the extent of depression deterioration in individuals.

The relationship between grandparental childcare experience and relative handgrip strength among middle-aged and older adults

Delayed marriage and childbirth often result in individuals becoming grandparents in middle and older age, coinciding with significant physical transitions. This study examines the relationship between the intensity of grandparental childcare, measured in terms of time-commitment over the last year, and relative handgrip strength among South Korea adults aged 45–84. Data from 3,742 participants with grandchildren were analyzed using the 2008–2010 waves of the Korean Longitudinal Study of Aging. After applying propensity score matching, a final sample of 286 participants was analyzed with multivariate logistic regression model. Results showed that grandparents who provided childcare for an average of less than 40 h per week (Odds Ratio [OR] = 3.62) were more likely to have lower handgrip strength compared to those without caregiving experience. Additionally, those over the age of 65 showed a similar trend (OR = 2.76). Conversely, grandparents with positive self-rated health were less likely to exhibit lower handgrip strength than those rating their health as moderate (OR = 0.28). Grandparents who provided care for more than half the year were also less likely to have lower handgrip strength than those who provided less frequent care (OR = 0.26). This study highlights grandparental childcare as both a vital family support mechanism and a factor influencing physical health. Findings on caregiving intensity, particularly the role of moderate weekly childcare hours and longer terms involvement, underscore the importance of aligning caregiving commitments with grandparents’ health perceptions and capacities. Developing guidelines for optimal childcare duration and recommending physical activities tailored to support grandparents’ well-being would further promote healthy aging within a family-centered caregiving system.