China Health And Retirement Longitudinal Study Research Articles

The combined effects of heatwaves, air pollution and greenery on the risk of frailty: a national cohort study

The associations between heatwaves and frailty, as well as the joint effects of heatwaves with air pollution and greenery, are currently unknown. This study leverages data from the China Health and Retirement Longitudinal Study (CHARLS), which collected information from 6,400 older adults between 2011 and 2018. Our outcome variable was frailty, as measured by the frailty index (FI > 0.21). Heatwaves were defined based on maximum temperature, incorporating four thresholds (≥ 97.5%, 97.5%, 92.5%, and 90%) and three durations (≥ 2, 3, and 4 days). These variables were considered as time-varying variables, representing the one-year exposure preceding survival events. Fine particulate matter (PM2.5) and greenery (normalized difference vegetation index (NDVI)) were utilized as indicators of air pollution and greenery exposure, respectively, and were treated as time-varying indicators concurrent with heatwaves.Time-varying Cox proportional hazards models were employed to assess the independent effects, as well as the multiplicative and additive interactions of heatwaves, air pollution, and greenery on the risk of frailty. These effects were quantified using hazard ratios (HRs), a traditional product term representing the ratio of HRs, and the relative excess risk due to interaction (RERI). Our findings indicate that heatwaves are associated with an increased risk of frailty, with HRs ranging from 1.035 (95% CI: 1.006–1.064) to 1.063 (95% CI: 1.028–1.101). We observed both a positive multiplicative interaction (HRs > 1) and an additive interaction (RERI > 0) between high level PM2.5 concentration, lack of greenery, and heatwaves. This study reveals that the combined effects exacerbate the adverse impact of heatwaves on the risk of frailty. Moreover, the combined effects of heatwaves, air pollution, and greenery exposure on frailty risk vary across age, gender, and educational attainment.

The relationship between childhood SES and health in middle and old age: evidence from China.

Drawing from the extended Grossman health capital and demand theory and the life course theory, this study examined whether childhood SES has direct and significant correlation with health in middle and old age in a specific historical context in China. A sample of 9,861 respondents was obtained from the China Health and Retirement Longitudinal Study (CHARLS). Childhood SES was measured by objective indices of recall. Health was assessed by self-reported, physician diagnosis and the Center for Epidemiologic Studies Depression Scale (CESD). The Propensity Score Matching (PSM) was used to estimate the treatment effect between childhood SES and later life health. The Karlson-Holm-Breen (KHB) method was employed to examine the associative mediation effects. Compared to respondents with low SES in childhood, respondents with high SES in childhood had, on average, 5.1% more likely to report their health as good, an average 2.4% lower prevalence of chronic diseases and an average 7.6% lower in the score of depression in middle and old age. The indirect relationships of childhood health, adulthood SES and adulthood lifestyle with health in middle and old age were all significant. SES upward mobility in adulthood can diminish the association between childhood disadvantage and poor health in middle and old age. The health effects of childhood SES can persist into middle and old age, this is more noticeable in rural areas, particularly in females. The critical period, cumulative risk and social mobility models produce synergistic effects in China. Our results also promote a paradigm shift in health interventions from old age to early life for health-vulnerable populations.

Specific depressive symptoms, body mass index and diabetes in middle-aged and older Chinese adults: Analysis of data from the China Health and Retirement Longitudinal Study (CHARLS)

BackgroundThis study examined the association between specific depressive symptoms and incident diabetes, and whether overweight or obesity mediates this relationship among middle-aged and older adults in China. MethodsIn a nationally representative prospective cohort study of 11,893 middle-aged and older Chinese adults without baseline diabetes, we used Cox models to assess the association between depressive symptoms and diabetes. The quantile g-computation (qgcomp) model evaluated the contribution of 10 specific depressive symptoms to diabetes risk, and a two-stage regression method explored the mediation effect of overweight or obesity. ResultsOver a median follow-up of 7.1 years, 1,314 cases of diabetes were identified. Elevated depressive symptoms were associated with increased diabetes risk (HR 1.23; 95 % CI 1.09–1.38). Eight out of 10 depressive symptoms were significantly associated to diabetes, with loneliness (weight = 18 %; HR 1.23; 95 % CI 1.10–1.39), restless sleep (weight = 17 %; HR 1.16; 95 % CI 1.04–1.29), and bother (weight = 15 %; HR 1.19; 95 % CI 1.07–1.33) being the primary contributors. Mediation analysis showed that overweight and obesity reduced the depression-diabetes risk association by 8.21 % and 12.61 %, respectively. LimitationsDiagnosis of diabetes was self-reported. ConclusionsEight out of ten specific depressive symptoms were associated to diabetes, overweight and obesity may partially mitigate the effect of depressive symptoms on diabetes among middle-aged and older adults in China. Clinical implicationsOur results highlight the importance of tailoring diabetes prevention and management strategies according to specific depressive symptoms among middle-aged and older adults in China.

The effect of community environment on the trajectory of depressive symptoms and cohort differences among middle-aged and older Chinese adults.

Urbanization has changed the living environment of middle-aged and older Chinese adults, but it also brings certain mental pressure to them. Few studies have explored the effect of community environment on the development trajectory and the cohort differences of depressive symptoms in Chinese individuals. Based on the longitudinal data of the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2020, using three-level hierarchical linear growth model, this study examined the effect of community environment on the trajectory of depressive symptoms and cohort differences among middle-aged and older Chinese adults in five cohorts from 1920 to 1929, 1930-1939, 1940-1949, 1950-1959, and 1960-1966. The results of this study showed that middle-aged and older adult individuals who lived in neighborhoods with better community physical and social environments had a protective effect on depressive symptoms. There was a cohort difference in the development of depressive symptoms among middle-aged and older Chinese adults. The baseline depressive symptoms in the later birth cohorts were higher than those in the earliest cohort, and the development rate were also significantly higher. The role of community environment in the development rate of depressive symptoms among middle-aged and older adult individuals varied across the cohort. A better community social environment had a more significant moderating effect on the development rate of depressive symptoms in the early birth cohort (1930-1939), and a better physical environment had a more significant moderating effect on the development rate of depressive symptoms in the 1940-1949 cohort. Under the strategic background of healthy aging in China, the construction and improvement of community environment should become an important part of coping with the realistic challenges of the aging population, such as the expanding scale of depressed population among the middle-aged and older adult individual.

Association between changes in depressive symptoms and risk of anemia: from the China Health and Retirement longitudinal study

BackgroundPrevious studies have reported that anemia was associated with depression, but the association between changes in depressive symptoms and the risk of anemia was unclear. This study aimed to explore whether changes in depressive symptoms were associated with anemia among the middle-aged and elderly adults.MethodsA total of 6112 patients aged 45 years and older from the China Health and Retirement Longitudinal Study (CHARLS) were included in this analysis. Elevated Depression Symptoms (EDS) was defined as the Center for Epidemiological Studies Depression Scale-10 score ≥ 10. Depression status was defined as no depressive symptom [no EDS at Wave 1 (2011–2012) and Wave 2 (2013–2014)], decreasing depressive symptoms (EDS at Wave 1, no EDS at Wave 2), increasing depressive symptoms (no EDS at Wave 1, EDS at Wave 2), persistent depressive symptoms (EDS at Wave 1 and Wave 2). Multivariable logistic regression analyses were conducted to estimate the relationships between depressive symptoms and the changes and risk of anemia.ResultsDuring the follow-up of Wave 1 and Wave 3 (2015–2016), 906 participants (14.82%) developed anemia, the multivariable-adjusted odds ratio for the depressive symptom compared with the no depressive symptom was 1.24 (95% CI, 1.12–1.58) for anemia. From Wave 2 to Wave 3, there were 828 participants (14.62%) diagnosed with anemia. Compared to participants with no depressive symptom, those with persistent depressive symptoms during Wave 1 and Wave 2 had the significantly elevated risk of anemia (odds ratio 1.44, 95% CI 1.21–1.84).ConclusionsThe present study demonstrated that baseline depressive symptoms and changes in depressive symptoms were associated with increased risks of anemia.

Effects of activity participation and cognitive levels on depression in middle-aged and older adults with chronic illness: a national cross-sectional study.

The world population is rapidly aging, and depression mainly affects middle-aged and older adults with chronic diseases and cognitive impairments. The sample for this study was obtained from the China Health and Retirement Longitudinal Study (CHARLS) public database. The sample size for inclusion was 12,767. There were 6,773 females and 5,994 males, with an overall low level of education. This study aims to provide a theoretical and practical reference basis for the clinical non-pharmacological treatment of depression in middle-aged and older adults (age ≥ 50 years) with chronic diseases. Additionally, the study seeks to promote the development of mental health interventions for middle-aged and older adults (age ≥ 50 years) with chronic diseases, ultimately enhancing the sense of well-being and quality of life for this demographic. Cognitive functioning and depressive symptoms of the study participants were assessed using the Mini-Mental State Examination Scale (MMSE) and the short version of the Center for Epidemiological Studies Depression Scale (CESD-10). Binary logistic regression results showed that among middle-aged and older adults (age ≥ 50 years) with chronic diseases, participation in physical activity [OR = 1.397; 95% CI (1.181-1.651); p < 0.05] was more effective than participation in social activities [OR = 0.997; 95% CI (0.924-1.076); p < 0.05] for preventing depression. Those with cognitive impairment [OR = 1.206; 95% CI (1.089-1.335); p < 0.05] were more likely to experience depression than those without cognitive impairment. Activity participation (physical activity and social activity) had a more significant effect on mild and moderate depression compared to no depression, and cognitive level had a more pronounced effect on moderate depression [OR = 1.491; 95% CI (1.278-1.740); p < 0.05] and major depression [OR = 2.231; 95% CI (1.282-3.884); p < 0.05]. Within the specific cohort of middle-aged and older adults (age ≥ 50 years) with chronic diseases, both activity participation and cognitive level exert a significant influence on the prevention and intervention of depression. Engagement in physical activity, participation in social activities, and enhanced cognitive functioning emerged as protective factors against depression. Therefore, the policy-maker should strengthen the prevention and treatment of depression in a comprehensive manner through the promotion of physical and social activities and the enhancement of cognitive level, so as to safeguard the mental health of middle-aged and older adults with chronic diseases.

Impact of medical-nursing combined policy pilot on hospitalization frequency of middle-aged and older patients with chronic diseases: a quasi-experimental study based on China Health and Retirement Longitudinal Study.

To address the growing burden of older adult care, the Chinese government has introduced a policy that integrates medical care with elder care, launching two batches of national pilot projects. A majority of the older adult population suffers from one or more chronic diseases, with many experiencing multiple chronic conditions, necessitating support from both elder care and medical services. Using panel data from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2011 to 2020, this study employs the difference-in-difference (DID) model to analyze the impact of the integrated medical-nursing policy on the physical health of older patients with chronic diseases. The study found that the average annual number of hospitalizations for older individuals with one or more chronic diseases was 0.276. The integrated medical-nursing policy reduced hospitalizations by 0.0405. Additionally, the average annual hospitalization rate for older individuals with two or more chronic diseases was 0.339, higher than the former group. The integrated medical-nursing policy reduced hospitalizations by 0.0738 in this group. The pilot study demonstrates that the implementation of the integrated medical-nursing policy has significantly improved the physical health of older patients with chronic diseases. The government should promote these policies on a larger scale, explore various forms of integrated medical care, and provide more comprehensive medical and elder care services for older patients with chronic diseases.

Intraindividual Discordance Between Remnant Cholesterol and Low-Density Lipoprotein Cholesterol Associated With Incident Stroke: Results From 2 National Cohorts.

The atherogenic effect of remnant cholesterol is being increasingly acknowledged. This study aimed to explore the association of discordance between remnant cholesterol and low-density lipoprotein cholesterol with stroke onset using 2 Chinese national cohorts. We studied 11 139 participants from CHARLS (China Health and Retirement Longitudinal Study) and 5993 participants from CHNS (China Health and Nutrition Survey) aged 45 years or older. The discordance between remnant cholesterol and low-density lipoprotein cholesterol was defined using the difference in percentile units (>15 units). There were 988 (8.9%) and 128 (2.1%) stroke events reported during follow-up in the 2 cohorts. Elevated remnant cholesterol was significantly associated with a higher risk of total stroke in 2 cohorts. After adjusting for remnant cholesterol level, the discordantly high remnant cholesterol group was significantly associated with an increased stroke risk (CHARLS: subdistribution hazard ratio [sHR], 1.31 [95 CI, 1.10-1.55]; CHNS: sHR, 1.84 [95 CI, 1.15-3.08]) compared with the discordantly low group. Consistent results were shown even among those with optimal low-density lipoprotein cholesterol level. The discordance between remnant cholesterol and low-density lipoprotein cholesterol, representing the intraindividual discrepancy, is significantly associated with stroke onset among Chinese adults.

Grip strength and depressive symptoms in Chinese middle-aged and older adults: the mediating effects of cognitive function.

This study investigates the associations and mediating pathways between grip strength, cognitive function, and depression in middle-aged and elderly individuals in China. Utilizing data from the 2011 China Health and Retirement Longitudinal Study (CHARLS), we employed logistic regression and mediation analysis to examine the relationships and mediating factors between grip strength, cognitive function, and depression, while adjusting for potential confounders. The study included 6,841 participants, of whom 1,734 (25.35%) exhibited symptoms of depression. Our findings indicate that weak grip strength is significantly associated with an increased risk of depression (OR: 1.57, 95% CI: 1.32-1.87) among the middle-aged and elderly population. Conversely, good cognitive function was found to be protective against depression (OR: 0.94, 95% CI: 0.93-0.95). Grip strength indirectly affected depression through cognitive function, accounting for 9.4% of the total effect (β = -0.008, 95% CI [-0.013, -0.004]). This mediating effect was 23.8% in men (β = -0.013, 95% CI [-0.020, -0.007]); and 23.2% in those aged 60 years and over (β = -0.015, 95% CI [-0.022, -0.009]). This study highlights that weak grip strength increases risk of depressive symptoms, and adequate cognitive function can mitigate the association between weak grip strength and an increased risk of depression among middle-aged and elderly individuals in China. Psychological care for elder adults with weak grip strength and poor cognitive function should be strengthened.

Impact of physical activity on life satisfaction among middle-aged and older adults in China: A longitudinal national study.

This study examined the impact of physical activity on life satisfaction in middle-aged and older adults in China. Utilizing longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) conducted in 2015 and 2018, a total of 6484 participants aged 45 or older were included in the analysis. Data were collected on sociodemographic, health, and lifestyle variables, physical activity, and life satisfaction. Physical activity was categorized into 3 levels: low (71%), moderate (25%), and high (4%). Ordinal logistic regression and subgroup analysis were used to examine the effect of baseline physical activity on life satisfaction, including the examination of interaction effects. After adjusting for age, gender, education, marriage, residence, smoking, alcohol use, depressive symptoms, and self-rated health at baseline (2015), compared to the moderate-intensity physical exercise group, those in the low-intensity group experienced significantly lower levels of life satisfaction on follow-up (2018). In the subgroup analyses, a significant negative effect of low-intensity physical activity on life satisfaction was found in all groups regardless of age, education, marital status, smoking, alcohol use, sleep duration, weight, presence of chronic diseases, or self-rated health. These results support the promotion of physical exercise to enhance life satisfaction among middle-aged and older adults in China.

Insulin resistance and sarcopenia: a prognostic longitudinal link to stroke risk in middle-aged and elderly Chinese population

BackgroundStroke is the leading cause of death in middle-aged and elderly people in China. Insulin resistance (IR) and sarcopenia are both closely associated with metabolic diseases. However, the relationship between these two indicators and stroke has not been fully investigated. The aim of this study was to investigate the relationship between IR and sarcopenia and the risk of new-onset stroke.MethodsUsing longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018, Cox proportional hazards models were used to determine the association between IR surrogate indicators and sarcopenia status with stroke incidence.ResultsIn the present study, during a median 7 years of follow-up, we included 7009 middle-aged and elderly residents, of whom 515 presented with stroke incidence. After adjustment for potential confounders, both baseline IR surrogates and sarcopenia independently predicted stroke risk. In addition, co-morbidities had a higher risk of stroke than other groups. The positive association between TyG-WC and sarcopenia on stroke risk was particularly significant [HR (95% CI): 2.03 (1.52, 2.70)]. In subgroups of different ages and sexes, the combination of IR and sarcopenia is associated with the highest risk of stroke.ConclusionsWe found that IR and sarcopenia synergistically increase the incidence of stroke in older adults. This finding provides new perspectives for stroke detection and intervention and highlights the importance of early detection and management of IR and sarcopenia in older adults.

Determinants of Visual Impairment Among Chinese Middle-Aged and Older Adults: Risk Prediction Model Using Machine Learning Algorithms.

Visual impairment (VI) is a prevalent global health issue, affecting over 2.2 billion people worldwide, with nearly half of the Chinese population aged 60 years and older being affected. Early detection of high-risk VI is essential for preventing irreversible vision loss among Chinese middle-aged and older adults. While machine learning (ML) algorithms exhibit significant predictive advantages, their application in predicting VI risk among the general middle-aged and older adult population in China remains limited. This study aimed to predict VI and identify its determinants using ML algorithms. We used 19,047 participants from 4 waves of the China Health and Retirement Longitudinal Study (CHARLS) that were conducted between 2011 and 2018. To envisage the prevalence of VI, we generated a geographical distribution map. Additionally, we constructed a model using indicators of a self-reported questionnaire, a physical examination, and blood biomarkers as predictors. Multiple ML algorithms, including gradient boosting machine, distributed random forest, the generalized linear model, deep learning, and stacked ensemble, were used for prediction. We plotted receiver operating characteristic and calibration curves to assess the predictive performance. Variable importance analysis was used to identify key predictors. Among all participants, 33.9% (6449/19,047) had VI. Qinghai, Chongqing, Anhui, and Sichuan showed the highest VI rates, while Beijing and Xinjiang had the lowest. The generalized linear model, gradient boosting machine, and stacked ensemble achieved acceptable area under curve values of 0.706, 0.710, and 0.715, respectively, with the stacked ensemble performing best. Key predictors included hearing impairment, self-expectation of health status, pain, age, hand grip strength, depression, night sleep duration, high-density lipoprotein cholesterol, and arthritis or rheumatism. Nearly one-third of middle-aged and older adults in China had VI. The prevalence of VI shows regional variations, but there are no distinct east-west or north-south distribution differences. ML algorithms demonstrate accurate predictive capabilities for VI. The combination of prediction models and variable importance analysis provides valuable insights for the early identification and intervention of VI among Chinese middle-aged and older adults.

Atherogenic index of plasma and obesity-related risk of stroke in middle-aged and older Chinese adults: a national prospective cohort study.

The association between the atherogenic index of plasma (AIP) and stroke risk is uncertain. Overweight and obese individuals frequently develop atherosclerosis, suggesting AIP may mediate the relationship between body mass index (BMI) and stroke risk. This study investigates whether AIP mediates the BMI-stroke association and evaluates the interaction effects of AIP and BMI on stroke risk in middle-aged and older Chinese adults. This study analyzes data from the China Health and Retirement Longitudinal Study (CHARLS), an ongoing nationally representative prospective cohort study that began in 2011. It includes 8598 middle-aged and older Chinese adults without stroke at baseline. A mediation analysis, employing a novel two-stage regression method, was conducted to evaluate the indirect effect of BMI on stroke through AIP. During a median follow-up of 7.1years, 615 (7.2%) participants developed a stroke. After adjusting for confounders, AIP was significantly associated with stroke risk (hazard ratio [HR] per 1-SD increase, 1.24; 95% CI 1.14-1.35). Mediation analysis indicated that compared to normal weight, obesity similarly raised stroke risk by 78.0% (HR 1.78, 95% CI 1.40-2.27), with 29.67% (95% CI 14.27-45.08%) of the association mediated through AIP (HR 1.15, 95% CI 1.08-1.23). No significant multiplicative or additive interactions were observed between BMI and AIP on stroke. This study found that the AIP appeared to be associated with stroke risk and mediates the association between obesity and stroke among middle-aged and older Chinese adults.

Association between dynapenic abdominal obesity and arthritis among the middle-aged and older Chinese: a longitudinal study.

This study aimed to assess the longitudinal association between dynapenic abdominal obesity and new-onset arthritis among the middle-aged and older Chinese population. We included 6863 participants from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS). Dynapenia was defined as handgrip strength < 28kg for males, and < 18kg for females. Abdominal obesity was defined as a waist circumference ≥ 90cm for males and ≥ 85cm for females. Based on the definitions, all participants were divided into four groups: no dynapenia and no abdominal obesity (ND/NAO), abdominal obesity alone (ND/AO), dynapenia alone (D/NAO), and dynapenia and abdominal obesity (D/AO). The association between dynapenic abdominal obesity and new-onset arthritis was assessed by sex using the Poisson regression models. After a four-year follow-up, 1272 (18.53%) participants reported new-onset arthritis. Those in the D/AO group had a significantly increased risk of new-onset arthritis compared to those in the ND/NAO group (adjusted relative risk (RR): 1.34, 95% confidence interval (CI): 1.01-1.77). In females, the ND/AO (RR: 1.21, 95% CI: 1.03-1.43) and D/AO (RR: 1.39, 95% CI: 1.01-1.93) groups were associated with a higher risk of arthritis. This significant association was not observed in males. Our results indicated that the combined effect of dynapenia and abdominal obesity significantly increased the risk of new-onset arthritis in females, but this association was not observed in males.

Has the Development of Broadband Infrastructure Improved Household Energy Consumption in Rural China?

Digital infrastructure plays a crucial role in shaping household energy consumption behaviors, especially in the context of achieving carbon peaking and carbon neutrality goals in China. In this study, we explored the impact of broadband infrastructure on household energy consumption and clean fuel choices, using data from the China Health and Retirement Longitudinal Study (CHARLS). In a difference-in-differences (DID) framework, our findings indicate that the promotion of broadband infrastructure significantly increases rural household energy consumption and facilitates a transition to cleaner energy sources. Notably, households with better socioeconomic status, particularly those with higher education and income levels, benefit more from enhanced broadband internet access. Mechanism analysis reveals that the “Broadband China” policy can positively influence household consumption through several potential channels: fostering technological innovation, enhancing energy efficiency in cities, and improving overall environmental awareness. These findings contribute to our understanding of the role of broadband infrastructure in shaping household energy consumption patterns and have important implications for policymakers, particularly in the context of sustainable development and energy transition efforts.

Household fuel use and the regression from prehypertension to normotension among Chinese middle-aged and older adults: a cohort study.

To examine the association of household fuel use with prehypertension regression among middle-aged and older people based on the China Health and Retirement Longitudinal Study (CHARLS), we included a total of 3501 participants with prehypertension at baseline, and they were followed up from 2011-2012 to 2015-2016 with information on blood pressure and household solid fuel use (heating and cooking fuels). Cox proportional hazards regression models were used to explore the hazard ratio (HR) and 95% confidence interval (CI) between fuel use and prehypertension regression. Additionally, we investigated the impact of switching fuels (2011-2013) on the regression to normotension during the 4-year follow-up. Linear regression was used to examine the effect of household fuel use on changes in blood pressure. Compared to solid fuel users, those who used clean fuel for heating at baseline had a positive effect on the regression of prehypertension (HR: 1.28, 95% CI: 1.08-1.53). Participants who used clean fuels for both heating and cooking had increased odds for the regression of prehypertension (HR: 1.32, 95% CI: 1.09-1.60). Compared to consistent solid fuel users, those who consistently used clean fuel for heating had a higher likelihood of transitioning from prehypertension to normotension (HR: 1.36, 95% CI: 1.06-1.73) and exhibited 2.45 mmHg lower systolic blood pressure. In conclusion, household clean fuel use for heating was positively associated with the regression of prehypertension to normotension. Furthermore, switching from solid fuel to clean fuel for heating could reduce the risk of prehypertension in Chinese middle-aged and older adults.

Associations of caring for grandchildren and great-grandparents with depressive symptoms and life satisfaction in Chinese grandparents: The moderating roles of urban-rural residence and social participation.

This study aims to investigate the associations of caring for grandchildren and/or great-grandparents with depressive symptoms, as well as life satisfaction in Chinese grandparents, and analyze the moderating roles of urban-rural residence and social participation. A nationally representative sample of 2973 grandparents in families with great-grandparents and grandchildren were selected from the 2018 China Health and Retirement Longitudinal Study (CHARLS). The Center for Epidemiologic Studies Depression (CESD-10) and the single-item were used to measure depressive symptoms and life satisfaction. Social participation included participation in social and intellectual activities. The binary logistic regression model was employed to explore the relationship between caring and depressive symptoms, as well as life satisfaction in the whole participants, different urban-rural residence, and social participation groups, respectively. Caring was associated with depressive symptoms and life satisfaction (p < 0.05). A significant interaction existed between caring and urban-rural residence for depressive symptoms (interaction p = 0.029) and life satisfaction (interaction p = 0.027). Significant interactions were also found among caring, urban-rural residence, and social activities with depressive symptoms (interaction p = 0.025). In urban, caring for both was negatively related to depressive symptoms for the non-social activists, while in rural, caring for great-grandparents was positively associated with depressive symptoms for social activists (p < 0.05). Any new policy design related to preventing and reducing the possibility of mental disorders in Chinese grandparents should be tailored to heterogeneous subgroups who live in different rural-urban and social activities participation.

Research on the Effect of the Healthy Cities Pilot Policy on the Labor Supply Time of Middle-Aged and Elderly Workers in China

Against the backdrop of Healthy China and an aging population, there is an urgent need to explore the effect of the Healthy Cities Pilot Policy (HCPP) on residents’ labor supply. This study integrates the HCPP, residents’ health, and labor supply time into a unified analytical framework. Using data from the China Health and Retirement Longitudinal Study (CHARLS) spanning the period 2011–2020 and leveraging the quasi-natural experiment provided by China’s 2016 HCPP, we empirically investigate its effects on labor supply time among middle-aged and elderly workers. Our findings indicate: (1) HCPP increases average weekly working hours by 2.834 h in pilot cities. (2) HCPP significantly enhances residents’ health status in pilot cities, extending their healthy time. (3) Middle-aged and elderly workers allocate more of their extended healthy time to labor rather than leisure, potentially influenced by traditional Chinese perceptions of “ceaseless toil”. (4) The impact of HCPP on labor supply time exhibits group heterogeneity, with stronger promotion effects observed among vulnerable middle-aged and elderly groups characterized by older age, rural household registration, lower educational attainment, and lower income levels. This research offers insights for policymakers aiming to optimize health policies and promote sustainable development within Chinese society.

Effects of household solid fuel use on sarcopenia in middle-aged and older adults: evidence from a nationwide cohort study.

Household solid fuel use is common in global households and has been linked to changes in handgrip strength and muscle mass. However, whether household solid fuel use results in sarcopenia over time is not well elaborated. This study employed data from the 2011-2015 China Health and Retirement Longitudinal Study (CHARLS) that recruited 4,932 participants ≥45 years. The Cox proportional hazards regression model was conducted to estimate the impact of household solid fuel use for cooking and heating on sarcopenia development. The analysis was further stratified based on geographic position. Mediation analysis was employed to estimate the potential mediating effects of cognitive function and depressive symptoms associated with household solid fuel use and sarcopenia. Over the 4-year follow-up, 476 cases of sarcopenia were reported (9.65%), with 254 in males (10.82%) and 222 in females (8.59%). Cooking and heating with solid fuels increased the risk of sarcopenia (Cooking: HR 1.401, 95% CI 1.138-1.724; Heating: HR 1.278, 95% CI 1.040-1.571). Crop residue/wood burning correlated with higher sarcopenia risk (Cooking: 1.420, 95% CI 1.147-1.758; Heating: 1.318, 95% CI 1.062-1.635). Switching to clean cooking fuels significantly reduced sarcopenia risk (HR 0.766, 95% CI 0.599-0.979). Heating with solid fuels was associated with higher sarcopenia risk only in southern China (HR 1.375, 95% CI 1.102-1.715). Additionally, cognitive function and depressive symptoms partially mediated the link between household solid fuel use and sarcopenia. Household use of solid fuels is associated with an increased risk of sarcopenia. Restricting the use of solid fuels and focusing on cognitive function and depressive symptoms in solid fuel users can help decrease sarcopenia development.

Association of handgrip strength weakness and asymmetry with later life pain risk in middle-aged and older individuals: Results from four prospective cohorts.

The burden of pain in middle-aged and older adults is considerable and significantly increases healthcare expenditures. We aimed to investigate the roles of handgrip strength (HGS) weakness and asymmetry in predicting pain across four nationally representative cohorts. This longitudinal study utilized data from four major surveys: the Health and Retirement Study (HRS); the English Longitudinal Study of Ageing (ELSA); the Survey of Health, Ageing and Retirement in Europe (SHARE); and the China Health and Retirement Longitudinal Study (CHARLS). Multivariable cubic regression splines were employed to visually explore the nonlinear associations between HGS and pain in each cohort. The Cox proportional hazard model was applied to analyze the independent and combined relationship between HGS weakness and asymmetry and pain risk. We included 41,171 participants in the final analysis, with a mean follow-up period of 4.68 ± 2.61 years (50.7% female, mean age 64.3 ± 9.3 years). No nonlinear relationship was found between HGS and pain incidence (nonlinear p < 0.05 in ELSA and SHARE; >0.05 in CHARLS and HRS). After adjustment, the highest quartile groups had a significantly reduced risk of pain compared to the lowest quartile groups across all cohorts, with hazard ratios of 0.81 (0.74, 0.89) in CHARLS, 0.86 (0.77, 0.97) in HRS, 0.88 (0.77, 0.98) in ELSA, and 0.78 (0.73, 0.84) in SHARE. Participants with normal HGS had approximately 20% lower risk of pain compared to those with weak HGS. Each 5 kg increase in HGS was associated with decreased hazard ratios for pain: 0.95 (0.93, 0.97) in CHARLS, 0.97 (0.94, 0.99) in HRS, 0.96 (0.94, 0.99) in ELSA, and 0.94 (0.92, 0.95) in SHARE. The association between HGS asymmetry and pain risk was significant only in a few cohorts (HRS at 10%, 1.10 (1.03, 1.18); SHARE at 30%, 1.12 (1.05, 1.21)). No interaction effect between HGS weakness and asymmetry on pain risk was observed (all p-values for interaction >0.05). Our findings suggest that HGS can be used as an independent predictor of pain in middle-aged and older European, American, and Chinese populations. However, our results do not support the use of HGS asymmetry as an independent predictor of pain risk. It is necessary to establish appropriate criteria for HGS asymmetry across different populations. The use of both weak HGS and asymmetry as predictors of health outcomes requires further validation in more diverse populations.