Association between solid cooking fuel and cognitive decline: Three nationwide cohort studies in middle-aged and older population

Relationship Between Sarcopenia and the Trajectories of Depressive Symptoms Among Chinese Older Adults: The Mediating Effect of Social Participation

BACKGROUND

This study evaluated the relationship between sarcopenia and the trajectories of depressive symptoms among Chinese older adults and verified the mediating role of social participation.

METHOD

The sample included 1832 participants aged ≥ 60 years from five waves of the China Health and Retirement Longitudinal Study (CHARLS). The optimal trajectory class of depressive symptoms was identified using the latent growth mixture model (LGMM). The association between sarcopenia and the trajectories of depressive symptoms was assessed by multinomial logistic regression. The potential mediating effect of social participation was evaluated through mediation analysis. Subgroup and interaction analyses were also carried out.

RESULTS

The results showed that the depressive symptom score trajectory of the sarcopenia group was higher than that of the normal group. The depressive symptoms of the general participants had three trajectories: "Anterior high level," "Posterior high level," and "Stable low level". Sarcopenia was related to the increased odds of adverse trajectory of depressive symptoms ("Anterior high level" trajectory) (adjusted OR = 1.53, 95% CI: 1.02-2.30). Social participation mediated 10.69% of the association between sarcopenia and adverse trajectory of depressive symptoms. Sex, education, marital status, chronic disease, self-rated health status, and self-rated standard of living were modifiable factors affecting the relationship of sarcopenia and adverse trajectory of depressive symptoms.

CONCLUSION

Comprehensive measures including early screening and treatment for sarcopenia, the strengthening of social participation levels, and formulating targeted intervention strategies are recommended to alleviate depressive symptoms and enhance mental health.

Association between serum cystatin C and chronic lung disease in middle-aged and elderly Chinese: a CHARLS cross-sectional study

The dose-response relationship between cystatin C (CysC) levels and chronic lung disease (CLD) development remains unclear and warrants further investigation. A more in-depth study of the relationship between serum CysC levels and CLD prevalence based on data from the China Health and Retirement Longitudinal Study (CHARLS). A cross-sectional analysis of 10,275 middle-aged and older adults aged 45 years and older was conducted using 2015 CHARLS data. Binary logistic regression models, restricted cubic spline curves (RCS), and threshold effects analyses were used to explore the association between different CysC levels and CLD prevalence in the middle-aged and older population, and subgroup analyses were performed to verify the robustness of the findings. When CysC was used as a categorical variable, the risk of CLD was increased by 38% in the T3 group compared with T1 (P < 0.001), and when CysC was used as a continuous variable, the risk of CLD was increased by 96% for each unit increase in CysC level (P < 0.001). In addition, there was a nonlinear relationship between CysC levels and the risk of CLD prevalence (P for non-linearity < 0.012), and the risk of CLD prevalence increased significantly with increasing CysC levels when CysC levels ≥ 0.754 mg/L. When CysC ≥ 0.754 mg/L, we need to be highly concerned about the risk of developing chronic lung disease in middle-aged and older populations, and those aged 45-64 years should be the focus of screening.

Exploring association between ambient air pollution and glaucoma in China: a nationwide analysis with predictive modeling based on the China Health and Retirement Longitudinal Study

Background

Glaucoma, a leading global cause of blindness, has garnered increasing research attention in recent years concerning its potential association with environmental factors. This study investigates the influence of various environmental pollutants on glaucoma prevalence among middle-aged and older adult populations in China, a country with a high incidence of the disease.

Methods

Using data from 17,184 participants in the 2015 China Health and Retirement Longitudinal Study (CHARLS), individuals were grouped based on glaucoma diagnosis. Environmental pollutant exposure levels were derived from satellite-based spatiotemporal models. Standardized linear regression and restricted cubic spline (RCS) analysis were applied to evaluate the impact of pollutants on glaucoma across different covariate-adjusted models, while logistic regression was used to assess significant variables for constructing and evaluating a predictive model.

Results

After adjusting for covariates, six pollutants (PM2.5, PM10, PM1, NH4, Cl, and NO3) demonstrated significant associations with glaucoma incidence. Subsequent logistic regression revealed that the occurrence of glaucoma may be influenced by a combination of environmental pollutants (NH4 and NO3), regional categories, gender, age, educational level, and diabetes history.

Conclusion

In conclusion, this study offers a novel perspective on glaucoma risk prediction by integrating environmental pollutants, potentially contributing to enhanced preventive strategies for this condition.

Healthier lifestyles can modify the air pollutants effect on cardiovascular disease among the middle-aged and elderly

There is increasing evidence that air pollutants significantly increase the risk of cardiovascular disease (CVD). Nevertheless, less research has been conducted to date to reveal protective factors. Therefore, this study aims to indicate whether a healthy lifestyle can modify the effects of environmental pollution on CVD. This study screened 3010 participants from the China Health and Retirement Longitudinal Study (CHARLS) Wave 3 (2015). The study aimed to systematically demonstrate the impact of environmental pollution on CVD and elucidate the role of a healthy lifestyle. Air pollutant data were obtained from the China High Air Pollutant (CHAP) datasets. We analyzed the relationship between these pollutants and cardiovascular disease risk using generalized linear mixed models. In addition, healthy lifestyles were categorized as low, medium, and high; stratified analyses were conducted to estimate the effect of healthy lifestyles on the risk of CVD due to air pollutants. 607 had CVD among 3010 participants, and the three-year mean concentrations of the pollutants chloride ion (Cl-), nitrate ion (NO3-), particulate matter with a diameter of 10 micrometers or less (PM10), particulate matter with a diameter of 10 micrometers or less (PM1), particulate matter with a diameter of 10 micrometers or less (PM2.5) were each linked 1.37 (95%CI:1.22,1.54), 1.03 (95%CI:1.00,1.06), 1.02 (95%CI:1.01,1.03), 1.01 (95%CI:1.00,1.01), and 1.01 (95%CI:1.00,1.01) fold risk of CVD, respectively. For the subgroups of low, medium, and high according to the healthy lifestyle score in model 2, the average concentration of Cl- pollutant was each associated with 1.34 (1.12,1.62), 1.34 (1.12,1.61), and 1.32 (1.03,1.71) times risk with CVD, respectively. The NO3 - was each associated with 1.06 (1.02,1.11), 1.01 (0.97,1.05), and 0.98 (0.93,1.04) times risk with CVD, respectively. The PM1 was each associated with 1.03 (1.01,1.05), 1.01 (0.99,1.02), and 1.00 (0.97,1.02) times risk with CVD, respectively. The PM10 was each associated with 1.01 (1.00,1.01), 1.01 (0.99,1.01), and 1.00 (0.99,1.01) times risk with CVD, respectively. PM2.5 was each associated with 1.02 (1.01,1.03), 1.00 (0.99,1.01), and 1.00 (0.99,1.01) times risk with CVD, respectively. Exposure to these pollutants(Cl-, NO3-, PM10, PM1, PM2.5)is associated with higher risk of CVD, and healthier lifestyles can reduce the risk of CVD due to overall air pollutants.

Association of residential green space with risk of sarcopenia and the role of air pollution: Evidence from UK Biobank

This study aims to explore the association between residential green space exposure and sarcopenia, and the role of air pollutants in the association. This study utilized data from the UK Biobank. Residential green space and natural environment were assessed by the percentage of land covered by greenness within 300 m and 1000 m buffers. Logistic regression models were used to explore the associations of green space and natural environment with possible sarcopenia and sarcopenia. We explored the mediating role of air pollution mixtures in the above associations. Interactions between green space and air pollution were assessed on the multiplicative and the additive scales. A total of 430790 participants were included in this study, and 23637 (5.5%) possible sarcopenia and 769 (0.2%) sarcopenia cases were identified. Each 10% increment of green space and natural environment coverage was associated with lower risks of possible sarcopenia (odds ratio (OR): 0.968, 95% confidence interval (CI): 0.961, 0.976 in green space; OR: 0.968, 95%CI: 0.962, 0.975 in natural environment) and sarcopenia (OR: 0.958, 95%CI: 0.920, 0.999 in green space; OR: 0.961, 95%CI: 0.926, 0.998 in natural environment). Population-attributable fraction analyses revealed that lower green space and natural environment levels could attribute to 8.8% and 8.5% of possible sarcopenia, 17.0% and 15.4% of sarcopenia. The associations of green space and natural environment with possible sarcopenia status could be partially explained by reducing air pollution. We also identified a significant multiplicative interaction between air pollution mixtures and green space on possible sarcopenia. In summary, higher green space and natural environment levels were associated with lower risks of possible sarcopenia and sarcopenia. Both modification and mediation roles of air pollution were found in the association between green space and possible sarcopenia. Therefore, expanding green space and reducing air pollution are crucial strategies for mitigating the risk of sarcopenia and promoting healthy aging.

Association between household solid fuel use and cognitive frailty in a middle-aged and older Chinese population

Objectives

Our research intended to investigate the association between the solid fuels use and the risk of cognitive frailty (CF).

Methods

The research utilized data from the China Health and Retirement Longitudinal Study (CHARLS), a nationwide longitudinal study focusing on individuals aged 45 and older. A total of 8,563 participants without CF were enrolled from 2011 and followed up to 2015. Household fuel types include solid fuels (such as coal, crop residue, or wood-burning) and clean fuels (such as solar power, natural gas, liquefied petroleum gas, electricity, or marsh gas). CF was defined as the co-existence of cognitive impairment and physical frailty. Cox proportional hazards models were utilized to evaluate the relationship between the solid fuels use and the risk of CF. Furthermore, sensitivity analyses were conducted.

Results

Over a median follow-up of 4.0 years, 131 subjects were diagnosed with CF. We observed that the solid fuels use for cooking or heating increased the risk of developing CF compared to clean fuels, with HRs of 2.02 (95% CI: 1.25 to 3.25) and 2.38 (95% CI: 1.26 to 4.48), respectively. In addition, participants who use solid fuel for heating (HR: 2.38 [95% CI: 1.26, 4.48]) and cooking (HR: 2.02 [95% CI: 1.25, 3.25]) might experience an increased risk of CF. However, transitioning from solid to clean fuels for cooking could potentially reduce these risks (HR: 0.38 [95% CI: 0.16, 0.88]).

Conclusion

Household solid fuels utilization was closely associated with the risk of CF.

The association between indoor air pollution from solid fuels and cognitive impairment: a systematic review and meta-analysis

This study aimed to comprehensively and methodically evaluate the correlation between cognitive impairment and indoor air pollution from solid fuel used for cooking/heating. PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched up to December January 2023. 13 studies from three countries with a total of 277,001 participants were enrolled. A negative correlation was discovered between solid fuel usage for cooking and total cognitive score (β=-0.73, 95 % CI: -0.90 to -0.55) and episodic memory score (β=-0.23, 95 % CI: -0.30 to -0.17). Household solid fuel usage for cooking was considerably associated with a raised risk of cognitive impairment (HR=1.31, 95 % CI: 1.09-1.57) and cognitive decline (HR=1.24, 95 % CI: 1.18-1.30). Compared to continuous solid fuel use for cooking, sustained use of clean fuel and switching from solid fuel to clean fuel were associated with a lower risk of cognitive decline (OR=0.55, 95 % CI: 0.42-0.73; OR=0.81, 95 % CI: 0.71-0.93). A negative association was found between solid fuel usage for heating and total cognitive score (β=-0.43, 95 % CI: -0.59 to -0.26) and episodic memory score (β=-0.22, 95 % CI: -0.34 to -0.10). Our research provided evidence that exposure to indoor air pollution from solid fuel is a potential cause of cognitive impairment and cognitive decline. Making the switch from solid fuels to cleaner fuels could be an important step in preventing cognitive impairment in the elderly.

Association between indoor ventilation frequency and low muscle mass among older adults in China: a national cross-sectional research

Previous studies have established associations between indoor air pollution and loss of muscle mass. While indoor ventilation improves indoor air quality, its association with low muscle mass (LMM) remains unexplored. We investigated the association between indoor ventilation frequency (IVF) and LMM in older Chinese adults. Utilizing data from the China Longitudinal Healthy Longevity Survey (CLHLS), IVF was assessed via self-reported weekly window-opening frequency in each season of the past year. LMM was defined using appendicular skeletal muscle mass (ASM) prediction equations. Binary logistic regression models were employed to evaluate the association between IVF and LMM, with subgroup and sensitivity analyses conducted. After adjusting for covariates, participants with intermediate IVF (OR: 0.805; 95% CI: 0.669-0.969) and high IVF (OR: 0.818; 95% CI: 0.684-0.979) were 19.5% and 18.2% less likely to develop LMM, compared with participants with low IVF. The probability of LMM in the spring was 25.3% (OR: 0.747; 95% CI: 0.581-0.961) and 23.3% (OR: 0.767; 95% CI: 0.597-0.985) lower in the middle and high IVF elderly populations, respectively, whereas the probability of LMM in the spring was 36.5% (OR: 0.625; 95% CI: 0.474-0.824) and 34.1% (OR: 0.659; 95% CI: 0.501-0.868). The association between IVF and LMM was statistically significant (p < 0.05) in gender, age, residence, living arrangement, marital status, economic situation, work, smoking, drinking, exercise, cooking ventilation, life satisfaction, self-rated health, hypertension, diabetes, heart disease, dementia, and NO2. Interaction analyses showed a significant interaction effect between the drinking subgroup and IVF (P for interaction < 0.05). Higher IVF is significantly associated with a lower risk of LMM. Optimizing ventilation practices may mitigate LMM burden in older adults, informing personalized health strategies.

Long-term low-level ozone exposure and the incidence of type 2 diabetes mellitus and glycemic levels: A prospective cohort study from Southwest China

BACKGROUND

This study investigated the relationship between long-term low-level ozone (O3) exposure, type 2 diabetes mellitus (T2DM) incidence, and glycemic levels within a prospective cohort in Southwest China, especially in regions with relatively low air pollution levels.

METHOD

Between 2010 and 2020, the Guizhou Population Health Cohort Study (GPHCS) enrolled 9280 participants, who were followed up from 2016 to 2020. A total of 7317 participants (aged 18-95 years, mean 43.70 ± 14.89 years) were included in the final analysis. Time-dependent Cox regression models were used to evaluate the hazard ratios (HRs) between O3 exposure and T2DM incidence and its 95 % confidence intervals (CIs). Generalized linear model (GLM) assessed the association between O3 exposure and fasting blood glucose (FBG) levels.

RESULTS

During a median follow-up period of 6.58 (6.25, 8.42) years, 763 participants were diagnosed with T2DM. For every 1 standard deviation (SD) increase in O3 exposure (Mean ± SD: 67.23 ± 2.16 μg/m³) during the 6 years before baseline, the incidence of T2DM increased by 32.4 % (HR = 1.324, 95 % CI: 1.216, 1.442), while FBG levels rose by 0.081 mmol/L (β = 0.081, 95 % CI: 0.035,0.126). These associations persisted after adjusting for potential confounders, including PM2.5 and temperature. Stratified analyses revealed stronger associations in Han Chinese and urban populations.

CONCLUSION

This study provides robust evidence that even long-term exposure to low-level O3, below the World Health Organization (WHO) guideline value, is significantly associated with increased T2DM incidence and elevated FBG levels. These findings stress the need for stricter air pollution control measures to reduce the incident T2DM caused by long-term low-level O3 exposure and enhance public health protections.

Closing the gap in dementia research by community-based cohort studies in the Chinese population

China accounts for 1/5 of the global population and China faces a particularly heavy dementia burden due to its rapidly ageing population. Unique historical events, genetic background, sociocultural factors, lifestyle, and the COVID-19 pandemic further influence cognitive outcomes in the Chinese population. We searched PubMed, Web of Science, and Embase for community-based cohort studies related to dementia in the Chinese population, and summarized the characteristics, methodologies, and major findings published over the last 25 years from 39 cohorts. We identified critical research gaps and propose future directions, including enhancing sample representativeness, investigating China-specific risk factors, expanding exposure measurements to the whole life-span, collecting objective data, conducting administer-friendly domain-specific cognitive assessments, adopting pathological diagnostic criteria, standardizing biobank construction, verifying multi-modal biomarkers, examining social and genetic-environmental aspects, and monitoring post-COVID cognitive health, to approach high quality of dementia studies that can provide solid evidence to policy making and promote global brain health research.

Separate and joint associations of adverse childhood experiences and childhood socioeconomic status with depressive symptoms: The mediating role of unhealthy lifestyle factors

BACKGROUND

The associations between adverse childhood experiences (ACEs), childhood socioeconomic status (SES), and depressive symptoms (DS) remain unclear. This study aimed to assess the separate and joint associations of ACEs and childhood SES with DS and explore the potential mediating role of lifestyles.

METHODS

Data were obtained from the China Health and Retirement Longitudinal Study, which included 6879 participants. Cox proportional hazard models were used to evaluate the associations of ACEs and childhood SES with DS. Additive and multiplicative interactions between ACEs and childhood SES on DS were also examined. Causal mediation analyses were then conducted to quantify the mediating role of lifestyle factors in these associations.

RESULTS

During a median follow-up of 3.0 years, 1283 (18.7 %) participants were identified with DS. ACEs and low childhood SES were significantly associated with an increased risk of DS (ACEs [3 or more vs 0]: HR = 1.68, 95 % CI: 1.43-1.99; childhood SES [low vs high]: HR = 1.48, 95 % CI: 1.22-1.79). Compared to the no ACEs-moderate/high childhood SES group, the group with 1 or more ACEs-low childhood SES had the highest risk of DS (HR = 1.76, 95 % CI: 1.47-2.10). Significant additive interaction of ACEs with low childhood SES on DS was observed with relative excess risk due to an interaction of 1.21 (95 % CI: 0.27, 2.15). Sleep duration and smoking were identified as the potentially modifiable mediators.

CONCLUSIONS

The findings highlight the importance of promoting initiatives to address ACEs, low childhood SES, and unhealthy lifestyles as part of DS prevention strategies.

Effect of serum uric acid to creatinine ratio on cognitive function decline in middle-aged adults: Longitudinal evidence from CHARLS

BACKGROUND

Serum uric acid (SUA) was a predictor of cognitive function. The association of SUA/serum creatinine ratio (Scr), which represents renal function-normalized SUA and cognitive function is unknown.

OBJECTIVE

This study investigated the association of the SUA/Scr with cognitive function and the potential mediation effect of inflammation in the above relationship.

METHODS

This study used 1-5 waves of data from the China Health and Retirement Longitudinal Study. 3302 participants aged 45-60 years at baseline were included. Among them, 1129 who attended subsequent 2-3 waves were further included for cumulative exposure calculation to the SUA/Scr ratio. The Cox models were used to evaluate the impact of baseline SUA/Scr ratio and its cumulative exposure on cognitive function decline.

RESULTS

During a median follow-up of 8.6 years, there were 1512 (45.8%) cognitive function declined. After adjustment, the highest quartile of the SUA/SCr ratio was associated with the highest risk of cognitive function decline (Hazard ratio, 1.175; 95% confidence interval, 1.015-1.360). Restricted cubic spline showed a linear association between the SUA/Scr ratio and the risk of cognitive function decline (pnon-linear = 0.514). There were a stronger association of cumulative SUA/Scr ratio and its exposure burden with cognitive function decline [the highest versus lowest quartile: 1.635 (1.006-2.656), the high versus low group: 1.729 (1.212-2.466), respectively]. No significant mediating effect through white blood cell count or C-reactive protein in SUA/Scr ratio-cognitive function decline was found.

CONCLUSIONS

The SUA/Scr ratio was associated with a higher risk of cognitive decline, whereas the mechanism mediated by inflammation indicators was not found.

Use of open fires or closed solid fuel appliances for residential heating and cognitive decline in older adults

OBJECTIVES

Use of solid fuel appliances is a major contributor to air pollution. Indoor solid fuel burning for cooking and heating in lower-middle income countries is associated with lower cognitive function and faster decline. Less is known, however, about the potential risk to brain health from burning solid fuels in open fires and closed appliances for heating purposes only, particularly in higher income countries. The current study aimed to investigate the association between burning solid fuels for home heating and cognitive decline in older Irish adults, also testing whether results differ by sex/gender.

DESIGN AND PARTICIPANTS

The sample consisted of 4,537 participants aged 50 and older from The Irish Longitudinal Study on Ageing, a population-based cohort study. Participants were surveyed every two years between 2012 and 2018. Solid fuel use in 2012 (Wave 2) and cognitive function (word recall and verbal fluency) at waves 2, 3, 4 and 5 were analysed. Hierarchical linear mixed effects regression models were used to examine the association between solid fuel use and cognitive decline, controlling for multiple confounders.

RESULTS

There was a significant main effect of solid fuel use on cognitive function, such that individuals who reported using a solid fuel appliance or open fire as a main source of heating had lower cognitive scores than those who did not report such use at all waves, but there was no difference in the slope of the trajectory over time and no clear sex differences.

CONCLUSIONS

Older Irish adults who reported burning solid fuels (in an open fire or closed appliance) as a main way source of home heating had lower observed cognitive function across 6 years in TILDA but no evident faster decline than non-users. These findings further expand the evidence base on indoor air pollution and brain health.

Association between residential environment quality with mild cognitive impairment among middle and elderly adults in China

BACKGROUND

Most studies have focused on the effects of individual environmental risk factors on cognitive function; however, none have evaluated the association between residential environmental quality and cognitive impairment.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) were used to include 12,801 participants in a cross-sectional study and 8781 participants in a cohort study. Residential environmental quality was assessed using indicators such as particulate matter, types of household fuel, water sources, indoor temperature, and building types. Based on the residential environment quality score, participants were classified into three groups: comfortable (0-1 points), moderate (2-3 points), and poor (4-6 points). To evaluate the association between residential environmental quality and cognitive scores in the cross-sectional study, as well as the development of mild cognitive impairment (MCI) in the cohort study, ordinary least squares (OLS) regression and logistic regression models were applied.

RESULTS

In the cross-sectional study, cognitive scores and performance across four dimensions-orientation, computation, memory, and drawing-showed a significant decline from the comfortable to the poor residential environment groups. In the fully adjusted OLS regression model, scores across these dimensions were significantly reduced in the moderate and poor groups compared to the comfortable group (P for trend <0.001). The incidence of MCI from 2011 to 2018 was 10.1 %, 16.8 %, and 18.8 % for participants living in comfortable, moderate, and poor environments, respectively, with statistically significant differences among groups (all P < 0.07). Logistic regression analysis revealed an odds ratio of 1.25 (95 % CI: 1.02-1.53) for the moderate group and 1.31 (95 % CI: 1.04-1.65) for the poor group, compared to the comfortable group (P for trend<0.05).

CONCLUSIONS

An inferior residential environment is associated with lower cognitive scores and a higher rik of developing MCI in middle-aged and older Chinese adults.

Association between household solid fuel usage and trajectories of multimorbidity among middle-aged and older adults: a nationwide population-based cohort study

Background

This study aimed to explore the effect of household solid fuel usage on the multimorbidity trajectories among middle-aged and older adults.

Methods

Based on the 2011-2018 China Health and Retirement Longitudinal Study, the group-based trajectory modeling and the multinomial logistic regression model were used to explore the relationship between multimorbidity trajectories of older adults with different fuel types, duration of solid fuel usage, and potential interaction with PM2.5. Three multimorbidity trajectory patterns were identified by group-based trajectory modeling and labeled as "non-chronic morbidity" (no disease increase), "newly developing multimorbidity" (diseases grew from 0 to 2), and "multi-chronic multimorbidity" (diseases grew from 2 to 4).

Results

Compared to "Non-chronic morbidity," solid fuel was significantly associated with adverse multimorbidity trajectories, with an odds ratio (OR) and 95% confidence interval (CI) of 1.33 (1.11, 1.60) and 1.35 (1.18, 1.55) for newly developing and multi-chronic group, respectively. An adverse multimorbidity trajectory tended to be established with longer durations of solid fuel usage than "Non-chronic morbidity." For "Newly-developing multimorbidity," the ORs (95% CI) for 1-7 years and ≥ 8 years of solid fuel usage were 1.16 (0.94, 1.42) and 1.41 (1.12, 1.76), respectively, with P trend=0.001, while in "Multi-chronic multimorbidity," those were 1.25 (1.07, 1.47) and 1.68 (1.41, 2.00), respectively, with P trend <0.001. In the interaction analysis, the association between solid fuel usage and trajectories was significant only in areas where PM2.5 was lower than 50 μg/m3.

Conclusion

For the middle-aged and older Chinese population, a higher risk of multimorbidity trajectory is associated with household solid fuel usage, especially in the areas with lower PM2.5.

Longitudinal relationship between weight-adjusted waist index and depressive symptoms in middle-aged and older Chinese adults: A prospective cohort study

BACKGROUND

The association between obesity and depressive symptoms remains controversial. The Weight-adjusted waist index (WWI) shows advantages in assessing central obesity. This study aimed to investigate the longitudinal relationship between WWI and depressive symptoms.

METHOD

This prospective cohort study utilized data from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2011-2020. Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depressive Symptoms Scale (CESD-10) scores. Linear mixed models were used to examine longitudinal associations.

RESULTS

A total of 6835 participants over the age of 45 were included. WWI was positively associated with CESD-10 scores (β per 1 SD increase = 0.052SD; 95%CI: 0.021 to 0.083SD) and was linked to a faster increase in CESD-10 scores over time (β = 0.095SD/year; 95%CI: 0.090 to 0.100 SD/year). Conversely, BMI was negatively associated with CESD-10 scores (β per 1 SD increase = -0.067SD; 95%CI: -0.097 to -0.038SD). However, the negative association between BMI and CESD-10 scores weakened over time (β per 1 SD increase = 0.008SD/y; 95%CI: 0.003 to 0.013 SD/y). Nonlinear associations were detected between both WWI and BMI with CESD-10 scores.

LIMITATIONS

Self-reported depressive symptoms assessments may have introduced information bias. The observational design limits ruling out unobserved confounding factors.

CONCLUSIONS

Our findings highlight the association between WWI and the long-term progression of depressive symptoms in middle-aged and older adults. WWI may enhance our understanding of the link between obesity and depressive symptoms and could be superior to BMI in predicting depressive symptom progression.

The impact of living environmental factors on cognitive function and mild cognitive impairment: evidence from the Chinese elderly population

OBJECTIVES

Mild cognitive impairment represents a pivotal stage in the cognitive decline of older adults, with a considerable risk of advancing to dementia. Recognizing how living environmental factors affect cognition is crucial for crafting effective prevention and intervention strategies. This study seeks to elucidate the relationship between various living environmental factors and cognitive function, with a specific focus on mild cognitive impairment, within a Chinese elderly population.

METHODS

This is a cross-section and longitudinal study. Utilizing data from CHARLS, our cross-sectional analysis included 4,401 participants, while the cohort study comprised 3,177 individuals. We assessed living environmental factors based on household fuel types, water sources, indoor temperatures, residential building types, and ambient PM2.5 levels. We employed multiple linear regression for cross-sectional analyses and Cox proportional hazards regression models for longitudinal assessments to determine the effects of living environments on cognitive function and MCI risk. Stratified analyses, interaction tests, and sensitivity analyses were conducted to further validate our findings.

RESULTS

The findings revealed that, compared to those in high-risk environments, participants in low-risk settings exhibited higher cognitive scores (β = 1.25, 95%CI: 0.85, 1.65), better mental status (β = 0.70, 95%CI: 0.48, 0.92), and improved episodic memory (β = 0.27, 95%CI: 0.13, 0.41). Over a 7-year follow-up, the use of low-risk living environments (HR = 0.67, 95%CI: 0.49, 0.91), including clean fuels (HR = 0.74, 95%CI: 0.57, 0.95) and tap water (HR = 0.84, 95%CI: 0.71, 1.00), demonstrated a protective effect against MCI development. This correlation remained significant regardless of age, gender, residence, education level, smoking, alcohol consumption, and depression.

CONCLUSION

This research provides substantial evidence that living environmental factors significantly affect cognitive function and MCI risk in Chinese older adults. Enhancing living conditions may be a key strategy for promoting cognitive health and preventing MCI in this demographic. Further research is necessary to explore the long-term impacts and potential intervention strategies to optimize living environments for better cognitive outcomes in aging populations.

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

Background

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.

Methods

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.

Results

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.

Conclusion

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 between functional dependence and cardiovascular disease among middle-aged and older adults: Findings from the China health and retirement longitudinal study

BACKGROUND

The effect of different functional dependency types on cardiovascular disease (CVD) is largely unknown. Here, we aimed to investigate the association between functional dependence and CVD among middle-aged and older adults by conducting a cross-sectional and longitudinal study.

METHODS

The study sample comprised 16,459 individuals of ≥40 years (including 10,438 without CVD) who had participated in the 2011 China Health and Retirement Longitudinal Study (CHARLS). Functional dependence was categorized based on the "interval-of-need" method, while CVD was defined as physician-diagnosed heart disease or stroke. Cox proportional hazard regression was employed to assess the effects of functional dependence on CVD. Moreover, patients were grouped according to the functional status changes, and the impact of these changes on CVD was observed. Heterogeneity, subgroup, and interaction analyses were used to evaluate the consistency of the study findings. Finally, a mediation analysis was performed to estimate the potential mediation effects on the relationship between functional dependence and CVD risk.

RESULTS

CVD prevalence in the overall study population was 13.73 % (2260/16,459), while its prevalence among individuals with functional independence, low dependency, medium dependency, and high dependency was 9.60 % (1085/11,302), 14.25 % (119/835), 17.72 % (115/649), and 25.01 % (941/3763), respectively. Additionally, medium (odds ratio: 1.33, 95 % confidence interval: 1.06-1.68) and high functional dependency (1.55, 95 % CI: 1.38-1.75) were associated with CVD. A total of 2987 (28.62 %) participants with CVD were identified during the 9-year follow-up, with 4.85 % (145/2987) of the CVD cases being attributed to functional dependence. The individuals with medium (HR: 1.20, 95 % CI: 1.01-1.44) and high functional dependency (1.25, 95 % CI: 1.14-1.37) were more likely to develop CVD than their peers with functional independence. Furthermore, persistent functional dependence (HR: 1.72, 95 % CI: 1.52-1.94) and transition from functional independence to dependence (1.79, 95 % CI: 1.61-1.98) were associated with a higher CVD risk than continuous functional independence. Hypertension and diabetes may partially mediate CVD caused by functional dependence.

CONCLUSION

Functional dependence is associated with high CVD risk. Therefore, appropriate healthcare attention must be directed towards functionally dependent populations to protect their cardiovascular health.

Association of healthy diet score and adiposity with risk of colorectal cancer: findings from the UK Biobank prospective cohort study

PURPOSE

To explore the joint association of dietary patterns and adiposity with colorectal cancer (CRC), and whether adiposity mediates the relationship between dietary patterns and CRC risk, which could provide deeper insights into the underlying pathogenesis of CRC.

METHODS

The data of 307,023 participants recruited between 2006 and 2010 were extracted from the UK Biobank study. Healthy diet scores were calculated based on self-reported dietary data at baseline, and participants were categorized into three groups, namely, low, intermediate, and high diet score groups. Cox regression models with hazard ratios (HRs) and 95% confidence intervals (CIs) were used to estimate the effects of the healthy diet score on CRC incidence, adjusting for various covariates. Furthermore, the mediation roles of obesity and central obesity between the healthy diet score and CRC risk were assessed using a counterfactual causal analysis based on Cox regression model. Additionally, joint association between dietary patterns and adiposity on CRC risks was assessed on the additive and multiplicative scales.

RESULTS

Over a median 6.2-year follow-up, 3,276 participants developed CRC. After adjusting for sociodemographic and lifestyle factors, a lower risk of CRC incidence was found for participants with intermediate (HR = 0.83, 95% CI: 0.72 to 0.95) and high diet scores (HR = 0.73, 95% CI: 0.62 to 0.87) compared to those with low diet scores. When compared with the low diet score group, obesity accounted for 4.13% and 7.93% of the total CRC effect in the intermediate and high diet score groups, respectively, while central obesity contributed to 3.68% and 10.02% of the total CRC risk in the intermediate and high diet score groups, respectively. The mediating effect of adiposity on CRC risk was significant in men but not in women. Concurrent unhealthy diet and adiposity multiplied CRC risk.

CONCLUSION

Adiposity-mediated effects were limited in the link between dietary patterns and CRC incidence, implying that solely addressing adiposity may not sufficiently reduce CRC risk. Interventions, such as improving dietary quality in people with adiposity or promoting weight control in those with unhealthy eating habits, may provide an effective strategy to reduce CRC risk.

Switching indoor fuels and the incidence of physical-psychological-cognitive multimorbidity: A prospective cohort study

BACKGROUND

In developing countries, including China, solid-fuel-based heating and cooking is common. For older people, the multimorbidity prevalence is exceptionally high. Nevertheless, studies on the associations of indoor solid fuels use, especially switching fuels types, on multimorbidity in middle-aged and older people is scarce.

METHODS

Data from five waves of the China Health and Retirement Longitudinal Study were used in this study. Indoor fuels were classified as solid or clean fuels. Physical-psychological-cognitive multimorbidity (PPC-multimorbidity) was defined as the simultaneous presence of three disease types (physical illness, psychological disorders, cognitive impairment). Using Cox proportional risk models, hazard ratios (HRs) and 95 % confidence intervals (95 % CI) were calculated to investigate the associations of heating- and cooking-related baseline indoor fuels and switching indoor fuels with PPC-multimorbidity incidence.

RESULTS

In the heating (n=3121, mean age=56.55 years, male proportion=54.25 %) and cooking (n=3574, mean age=56.67 years, male proportion=52.94 %) analyses, 75.07 % and 45.64 % of the participants used solid fuels at baseline, and 564 (18.07 %) and 613 (17.15 %) PPC-multimorbidity cases were diagnosed during follow-up, respectively. Participants with baseline heating- and cooking-based solid fuels use had greater PPC-multimorbidity incidences [HRs (95 % CIs): 1.23 (0.98, 1.55) and 1.44 (1.21, 1.73)], respectively. Additionally, combined baseline heating- and cooking-based solid fuels use was associated with even greater PPC-multimorbidity incidence [HR (95 % CI): 1.55 (1.18, 2.04)]. Persistent solid fuels use obviously increased the PPC-multimorbidity incidence [HRs (95 % CIs): 2.43 (1.67, 3.55) for heating and 2.63 (2.03, 3.40) for cooking]. Moreover, switching from solid to clean fuels was associated with a significantly decreased PPC-multimorbidity incidence [HRs (95 % CIs): 0.27 (0.20, 0.35) for heating and 0.36 (0.28, 0.46) for cooking].

CONCLUSIONS

Long-term solid-fuels use is associated with an increased PPC-multimorbidity incidence, and switching to cleaner fuels is associated with a decreased PPC-multimorbidity incidence in adults aged ≥45 years.

Contribution of diversity of social participation on the mental health of humanitarian migrants during resettlement

AIMS

By the end of 2022, an estimated 108.4 million individuals worldwide experienced forced displacement. Identifying modifiable factors associated with the mental illness of refugees is crucial for promoting successful integration and developing effective health policies. This study aims to examine the associations between the changes in the diversity of social participation and psychological distress among refugees throughout the resettlement process, specifically focusing on gender differences.

METHODS

Utilizing data from three waves of a longitudinal, nationally representative cohort study conducted in Australia, this study involved 2399 refugees interviewed during Wave 1, 1894 individuals interviewed during Wave 3 and 1881 respondents during Wave 5. At each wave, we assessed psychological distress and 10 types of social participation across 3 distinct dimensions, including social activities, employment and education. The primary analysis employed mixed linear models and time-varying Cox models. Gender-stratified analyses and sensitivity analyses were performed.

RESULTS

Refugees engaging in one type or two or more types of social participation, compared with those not engaging in any, consistently had lower psychological distress scores (β = -0.62 [95% confidence interval (CI), -1.07 to -0.17] for one type of social participation; β = -0.57 [95% CI, -1.04 to -0.10] for two or more types of social participation) and a reduced risk of experiencing psychological distress (hazard ratio [HR] = 0.81 [95% CI, 0.65-0.99] for one type of social participation; HR = 0.77 [95% CI, 0.61-0.97] for two or more types of social participation) during the resettlement period. When stratifying the results by gender, these associations in the adjusted models only remained significant in male refugees. Moreover, three specific types of social participation, namely sporting activities, leisure activities and current employment status, were most prominently associated with a reduced risk of psychological distress.

CONCLUSIONS

The findings of this cohort study suggest that social participation was consistently associated with reduced risks of psychological distress among male refugees during resettlement. These findings highlight the significance of promoting meaningful social participation and interaction may be an effective strategy to improve the mental health of refugees and facilitate their successful integration into society, especially among male refugees.

Relationship of solid fuels use with cognitive function and efficacy of switching to cleaner fuels or using ventilation: A systematic review and meta-analysis

BACKGROUND

A growing number of studies have examined the relation between solid fuels use and cognitive function in the mid-elderly, but results are inconsistent. Therefore, a systematic review and meta-analysis was carried out to evaluate their relevance and the efficacy of switching to cleaner fuels or using ventilation.

METHOD

We used PubMed, Web of Science, and Cochrane Library databases to identify 17 studies in which the primary outcome variable was cognitive function decline or cognitive disorders, and the exposure measure was solid fuels use. The final search date of August 31, 2023. The effect size of odds ratio (OR), regression coefficient (β), and 95% confidence interval (CI) were pooled. Heterogeneity and the possibility of publication bias were assessed by using the Q-statistic and Begg's test, respectively.

RESULT

Among the 17 included papers, the study participants were ≥45 years old. Eleven studies assessed the relationship between solid fuels use and cognitive function decline [number of studies (n) = 11, β = -0.144; I2 = 97.7%]. Five studies assessed the relationship between solid fuels use and cognitive disorders (n = 5, OR = 1.229; I2 = 41.1%). Switching from using solid fuels to clean fuels could reduce the risk of cognitive function decline as compared to those who remained on using solid fuels (n = 2; β = 0.710; I2 = 82.4%). Among participants using solid fuels, who cooked without on ventilated stoves were correlated with an enhanced risk of cognitive disorders as compared to participants who cooked with ventilated stoves (n = 2; OR = 1.358; I2 = 44.7%).

CONCLUSION

Our meta-analysis showed a negative relationship between solid fuels use with cognitive function, and a positive relationship with cognitive disorders. Cleaner fuels, using ventilation, improved cookstoves can reduce the adverse health hazards of solid fuels use.

Household polluting cooking fuels and intrinsic capacity among older population: A harmonized nationwide analysis in India and China

BACKGROUNDS

Household polluting cooking fuels, as an important changeable behavior, are related to various detrimental health effects among the elderly. There is limited research on the association between polluting cooking fuel use and intrinsic capacity (IC) as an indicator of healthy aging. This study aimed to evaluate the above-mentioned association in India and China, where polluting cooking fuel use is common.

METHODS

We enrolled 33,803 participants aged ≥60 years from two nationally representative studies: the Longitudinal Aging Study in India and the China Health and Retirement Longitudinal Study. Polluting cooking fuel use was defined as a self-report of using wood, coal, kerosene, crop residue, or dung. IC was measured by five aspects, including locomotion, cognition, vitality, sensory, and psychological capacity. The random-effects mixed linear regression and logistic regression with population weighting were performed. Multivariable-adjusted model and propensity score were used to adjust for potential confounders.

RESULTS

A total of 47.54 % and 59.32 % of elderly adults reported primary cooking using polluting fuels in India and China, respectively. Using polluting cooking fuels was consistently associated with IC decline; particularly, cognitive capacity was the most susceptible domain. In India, participants using polluting fuels had a 1.062 (95 % confidence interval [CI]: 1.047-1.078) times risk for IC deficits, whereas more prominent results were observed in China (odds ratio [OR]: 2.040, 95 % CI: 1.642-2.533). Such harmful effects might be alleviated by transferring from polluting to clean fuels. Additionally, the duration of polluting fuel use was also positively associated with IC deficits.

CONCLUSION

This study provided substantial public implications on healthy aging for the elderly population at a global scale, strengthening the importance of health education and policy efforts to accelerate the transition from polluting to clean fuels.

Bidirectional associations between hearing difficulty and cognitive function in Chinese adults: a longitudinal study

Background

Middle-aged and older adults frequently experience hearing loss and a decline in cognitive function. Although an association between hearing difficulty and cognitive function has been demonstrated, its temporal sequence remains unclear. Therefore, we investigated whether there are bidirectional relationships between hearing difficulty and cognitive function and explored the mediating role of depressive symptoms in this relationship.

Method

We used the cross-lagged panel model and the random-intercept cross-lagged panel model to look for any possible two-way link between self-reported hearing difficulty and cognitive function. To investigate depressive symptoms' role in this association, a mediation analysis was conducted. The sample was made up of 4,363 adults aged 45 and above from the China Health and Retirement Longitudinal Study (CHARLS; 2011-2018; 44.83% were women; mean age was 56.16 years). One question was used to determine whether someone had a hearing impairment. The tests of cognitive function included episodic memory and intelligence. The Center for Epidemiologic Studies Depression Scale, which consists of 10 items, was used to measure depressive symptoms.

Results

A bidirectional association between hearing and cognition was observed, with cognition predominating (Wald χ2 (1) = 7.241, p < 0.01). At the between-person level, after controlling for potential confounders, worse hearing in 2011 predicted worse cognitive function in 2013 (β = -0.039, p < 0.01) and vice versa (β = -0.041, p < 0.01) at the between-person level. Additionally, there was no corresponding cross-lagged effect of cognitive function on hearing difficulty; rather, the more hearing difficulty, the greater the cognitive decline at the within-person level. According to the cross-lagged mediation model, depressive symptoms partially mediates the impact of cognitive function on subsequent hearing difficulty (indirect effect: -0.003, bootstrap 95% confidence interval: -0.005, -0.001, p < 0.05), but not the other way around.

Conclusion

These results showed that within-person relationships between hearing impairment and cognitive function were unidirectional, while between-person relationships were reciprocal. Setting mental health first may be able to break the vicious cycle that relates hearing loss to cognitive decline. Comprehensive long-term care requires services that address depressive symptoms and cognitive decline to be integrated with the hearing management.