Association between solid fuel use and cognitive impairment: A cross-sectional and follow-up study in a middle-aged and older Chinese population

Association between cognitive decline and depression in middle-aged and older adults: Findings from six large cohorts in different countries

BACKGROUND

The relationship between depression and cognition in middle-aged adults is a topic of interest. Whether poor cognitive function exacerbates depression remains controversial. We clarified the association between cognitive decline and depression based on six nationwide cohorts.

METHODS

89,056 participants were retrieved from six cohorts in Europe, North America, Asia and Africa. Each two consecutive interviews were collected as a sample set with a total of twenty-eight sample sets to assess changes in depression and cognitive function. Multiple linear regression was conducted within each sample set to evaluate the association between cognitive decline and depression. A two-stage meta-analysis was performed to obtain the average effect within each cohort and the overall effect excluding population and regional heterogeneity. Meta-regression and subgroup analysis were used to explore heterogeneity and potential effect modifiers.

RESULTS

Almost all sample sets indicated negative association between changes in cognitive function and depression scores. The average effects varied across regions: Korea (-0.150 [-0.175, -0.126]), Europe (-0.130 [-0.149, -0.112]), South Africa (-0.090 [-0.129, -0.060]), China (-0.083 [-0.137, -0.030]), Mexico (-0.063 [-0.084, -0.042]), and North America (-0.048 [-0.056, -0.040]). The overall effect excluding population and regional heterogeneity was -0.094 [-0.129, -0.060], and was robust across populations of different age, sex, alcohol consumption, daily living activities and marital status.

LIMITATIONS

The cross-sectional design limited our ability to determine causal relationships.

CONCLUSION

Cognitive decline was associated with the exacerbation of depression status in middle-aged and older adults worldwide. Country-level factors, rather than individual-level factors, are more likely to modify this effect.

Machine learning algorithms to predict mild cognitive impairment in older adults in China: A cross-sectional study

OBJECTIVE

This study aimed to explore the predictive value of machine learning (ML) in mild cognitive impairment (MCI) among older adults in China and to identify important factors causing MCI.

METHODS

In this study, 6434 older adults were selected based on the data of the China Health and Elderly Care Longitudinal Survey (CHARLS) in 2020, and the dataset was subsequently divided into the training set and the test set, with a ratio of 6:4. To construct a prediction model for MCI in older adults, six ML algorithms were used, including logistic regression, KNN, SVM, decision tree (DT), LightGBM, and random forest (RF). The Delong test was used to compare the differences of ROC curves of different models, while decision curve analysis (DCA) was used to evaluate the model performance. The important contributions of the prediction results were then used to explain the model by the SHAP value.The Matthews correlation coefficient (MCC) was calculated to evaluate the performance of the models on imbalanced datasets. Additionally, causal analysis and counterfactual analysis were conducted to understand the feature importance and variable effects.

RESULTS

The area under the ROC curve of each model range from 0.71 to 0.77, indicating significant difference (P < 0.01). The DCA results show that the net benefits of LightGBM is the largest within various probability thresholds. Among all the models, the LightGBM model demonstrated the highest performance and stability. The five most important characteristics for predicting MCI were educational level, social events, gender, relationship with children, and age. Causal analysis revealed that these variables had a significant impact on MCI, with an average treatment effect of -0.144. Counterfactual analysis further validated these findings by simulating different scenarios, such as improving educational level, increasing age, and increasing social events.

CONCLUSION

The ML algorithm can effectively predict the MCI of older adults in China and identify the important factors causing MCI.

Air pollution is linked to cognitive decline independent of hypersensitive C-reactive protein: insights from middle-aged and older Chinese

BACKGROUND

Long-term air pollution exposure and inflammation are considered to be associated with cognitive decline. However, whether air pollution exposure related cognitive decline is dependent on inflammation remains uncertain.

MATERIALS AND METHODS

The present study collected data from China Health and Retirement Longitudinal Study (CHARLS) at baseline in 2011, with a follow up period in 2015. Concentration of air pollutants (particles with diameters ≤ 1.0 μm [PM1], ≤ 2.5 μm [PM2.5], ≤ 10 μm [PM10], nitrogen dioxide [NO2] and ozone [O3]) were obtained from China High Air Pollutants (CHAP) dataset. Hypersensitive C-reactive protein (hs-CRP), a systemic inflammation marker, was measured in blood of subjects and cognitive function was assessed by standardized questionnaire.

RESULTS

A total of 6434 participants were included in the study. Lower exposure to PM2.5, PM1, PM10 and NO2 were associated with mitigated cognitive decline. The odds ratios (ORs) for air pollutants changes and cognitive decline and 95% confidence intervals (CIs) were as follows: PM2.5-0.934(0.925, 0.943), PM1- 0.945 (0.935,0.955), PM10-0.977(0.972,0.982) and NO2-0.962(0.950,0.975), respectively. Hs-CRP showed no significant correlation with cognitive decline or change in levels of air pollution. The interaction regression analyses, both unadjusted and adjusted, did not uncover any significant correlation between hs-CRP and air pollution with respect to cognitive decline. Bootstrap test exhibited no significant mediating effect of hs-CRP on the relationship between any air pollutants and cognitive decline, the indirect effects of hs-CRP in conjunction with exposure to different air pollutants were all found to be non-significant, with the following bootstrap CIs and p-values: PM2.5-1.000([1.000,1.000], P = 0.480),PM1-1.000([1.000,1.000], P = 0.230),PM10-1.000([1.000,1.000], P = 0.650), O3-1.000([1.000,1.000], P = 0.470), ΔNO2-1.000([1.000,1.000], P = 0.830) .

CONCLUSION

Ambient air pollution exposure was linked to cognitive decline independent of hs-CRP level.

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.

Does the household clean energy transition benefit the mental health of the elderly in rural China? Evidence from China health and retirement longitudinal study

Clean energy transition has become a key strategy in combating global air pollution. In 2017, China launched its "coal-to-gas" policy, which provided subsidies to households for their clean energy transition. While debates on this policy focus mainly on safety and cost concerns, few studies have examined the causal relationship between energy transition and its health benefits, particularly mental health. Using data from the China Health and Retirement Longitudinal Survey (CHARLS), this paper employs a difference-in-differences (DID) approach to estimate the impact of the "coal-to-gas" policy on the mental health of the rural elderly in China. The findings indicate that the policy significantly improved the cognitive status of the elderly, especially episodic memory, which saw a 10.4% increase relative to the sample mean. The policy also significantly boosted the proportion of households using clean cooking fuels by 5.8%. Further analysis suggests that the improved sleep quality from reduced indoor air pollution by household energy transition, as a mechanism, could explain these results. This study provides a timely assessment of the policy's effectiveness, highlighting the importance of indoor air pollution control by household energy transition.

Effect of particulate matter on cognitive function among middle-aged and older adults in China: An instrumental variable approach

Emerging studies have suggested the association of ambient air pollution with worse cognitive function; however, causal evidence remains scarce. We aimed to estimate the effect of particulate matter (PM) exposure on overall and domain-specific cognitive function. A total of 14,205 participants aged 45 years and above were drawn from the 2015 wave of the China Health and Retirement Longitudinal Study (CHARLS). Cognitive function was assessed using a standardized questionnaire consisting of two domains: episodic memory and mental status. Participants' exposure to city-level PM (PM1, PM2.5, and PM10) was evaluated using satellite-based spatiotemporal models. To avoid potential endogenous biases, an instrumental variable method with two-stage least squares estimation was employed to examine the effect of air pollution on overall and domain-specific cognitive function. Stratified analysis was further performed based on sociodemographic characteristics. We found PM exposure exertedsignificant adverse effects on overall and domain-specific cognitive function, with mental status being more adversely affected as compared to episodic memory. The effect of PM exposure was more pronounced with smaller particle sizes, with PM1 exhibiting the largest effect size. Moreover, participants with lower education attainment were more adversely affected by PM exposure. Our findings add additional evidence of the potential causal role of PM exposure in worsening overall and domain-specific cognitive function. Efforts to further reduce PM are needed to protect the cognitive health of the aging Chinese population.

Effects of major air pollutants on cognitive function in middle-aged and elderly adults: Panel data evidence from China Health and Retirement Longitudinal Study

Background

Although numerous studies have discussed about the impact of air pollution on cognitive function, a consensus has yet to be reached, necessitating further exploration of their relationship. The aim of this study is to reveal the effects of major air pollutants on cognitive function in Chinese middle-aged and older adults, while considering the lagged effects of pollution.

Methods

Panel data were constructed by integrating the air pollutants concentration (particulate matter diameter ≤1 µm (μm) (PM1), PM2.5, PM10, nitrogen dioxide (NO2), and ozone (O3)) among 28 provinces in China and the personal characteristics from China Health and Retirement Longitudinal Study participants during the period of 2011-2015. To explore the effects of single pollutants and their interactions on cognitive function, panel linear regression using ordinary least squares method was employed, and first-order lag effects (two-year interval) of air pollution were introduced into the models.

Results

Our study revealed that, after adjusting for confounding factors, higher levels of particulate matter (PM1, coefficient (Coef.) = -0.093, P = 0.001; PM2.5, Coef. = -0.051, P = 0.001; PM10, Coef. = -0.030, P = 0.001) and NO2 (Coef. = -0.094, P = 0.006) were associated with lower cognitive function scores among the participants. Moreover, the interaction between the five major pollutants exhibited a negative effect on cognitive function(Coef. = -2.89, P = 0.004).

Conclusions

PM1, PM2.5, PM10 have detrimental effects on the cognitive function of middle-aged and elderly adults in China, where increasing particle diameter correlates with a less negative impacts, providing theoretical underpinnings for the formulation of environmental protection policies.

Association of solid fuel use with cognitive function and the modifying role of lifestyle: A nationwide cohort study in China

BACKGROUND

As opposed to a healthy lifestyle, indoor air pollution from solid fuel use may be harmful for cognitive function. However, the extent to which lifestyle modifies the association between solid fuel use and cognitive function remains unknown.

METHODS

A total of 21,008 individuals aged 16 to 92 were enrolled in 2010 and followed up to 2014 in the China Family Panel Studies (CFPS). Cognitive function was assessed using standardized math and word tests in two waves. Solid fuel use at baseline was assessed by self-reporting of firewood, straw, or coal used for cooking. Lifestyle profile was classified into two groups (favorable vs. unfavorable) based on five modifiable lifestyle factors including alcohol drinking, smoking, body mass index, diet, and physical activity. Linear mixed-effects models were employed to assess the association of solid fuel use and lifestyle with cognitive function. The effect modification of lifestyle was analyzed.

RESULTS

A total of 49.7% of the study population used solid fuels for cooking and 17.4% had a favorable lifestyle. Solid fuel use was associated with a significant decrease in cognitive function (β = -0.29, 95% CI: -0.39, -0.19 for math test; β = -0.62, 95% CI: -0.84, -0.41 for word test). Lifestyle significantly modified this association (p-interaction: 0.006 for math test; 0.016 for word test), with the corresponding association being less pronounced among participants adhering to a favorable lifestyle compared to those with an unfavorable lifestyle.

CONCLUSION

A favorable lifestyle may attenuate the adverse association between solid fuel use and cognitive function. Adopting a favorable lifestyle has the potential to mitigate the adverse neurological effects due to indoor air pollution.

Comparative study of insulin resistance surrogate indices to predict mild cognitive impairment among Chinese non-diabetic adults

OBJECTIVE

The study aims to investigate the associations of triglyceride glucose (TyG), TyG combined with body mass index (TyG-BMI), metabolic score for insulin resistance (METS-IR), the triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), and the risk of mild cognitive impairment (MCI) in individuals without diabetes aged 45 and above.

METHODS

The most recent data in this study were from a cohort study, which sourced samples from the China Health and Retirement Longitudinal Study, spanning 2011 to 2018. The four indices' associations with MCI risk were analyzed using logistic regression. The predictive capacity was measured using the receiver operating characteristic (ROC) curve.

RESULTS

Over a 7-year follow-up, 1,261 individuals (31.34%) of the 4,027 participants developed MCI. Logistic regression analysis revealed significant associations between these surrogate indices and MCI. The findings for the highest quartile compared with the lowest quartile were as follows: TyG: 1.24 (95% CI: 1.02, 1.49); TyG-BMI: 1.38 (95% CI: 1.13, 1.68); METS-IR: 1.50 (95% CI: 1.09, 2.06); TG/HDL-C: 1.34 (95% CI: 1.10, 1.64). ROC analysis revealed that TyG, TyG-BMI, TG/HDL-C, and METS-IR demonstrated excellent discriminatory power for MCI, with area under the curve (AUC) values of 0.82 (95% CI: 0.80, 0.83), 0.82 (95% CI: 0.80, 0.83), 0.83 (95% CI: 0.80, 0.84), and 0.83 (95% CI: 0.80, 0.84), respectively. The four indices showed stronger ability to predict MCI risk in females compared to males.

CONCLUSION

Elevated levels of four indices are positively correlated with MCI risk. TyG-BMI and METS-IR demonstrate stronger capabilities in identifying MCI across both male and female populations. This suggests that early intervention in patients with elevated IR surrogate indices may help reduce the MCI.

The Association Between Solid Fuel Use and Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Hyperplasia in Sichuan, China: Cross-Sectional Study

Background

Benign prostatic hyperplasia (BPH) is a global age-related disease. It has been reported that over half of the Chinese male population aged 70 years or older are experiencing BPH. Solid fuel, which is the major source of household air pollution, has been reportedly associated with several adverse events, including sex hormone disorders. Due to the certain relationship between sex hormone levels and prostate disease, the relationship between solid fuel use and lower urinary tract symptoms (LUTSs) suggestive of BPH (LUTS/BPH) deserves further exploration.

Objective

This study mainly aimed to investigate the association between solid fuel use and LUTS/BPH.

Methods

The data used in this study were obtained from the West China Natural Population Cohort Study. Household energy sources were assessed using questionnaires. LUTS/BPH was evaluated based on participant self-reports. We performed propensity score matching (PSM) to reduce the influence of bias and unmeasured confounders. The odds ratio (OR) and 95% CI of LUTS/BPH for the solid fuel group compared with the clean fuel group were calculated. We also conducted stratified analyses based on BMI, metabolic syndrome, waist to hip ratio, drinking status, smoking status, and age.

Results

A total of 5463 participants were included in this study, including 399 solid fuel users and 5064 clean fuel users. After PSM, the solid fuel group included 354 participants, while the clean fuel group included 701 participants. Solid fuel use was positively correlated with LUTS/BPH before and after PSM (OR 1.68, 95% CI 1.31-2.15 and OR 1.81, 95% CI 1.35-2.44, respectively). In stratified analyses, the OR of the nonsmoking group was higher than that of the smoking group (OR 2.56, 95% CI 1.56-4.20 and OR 1.47, 95% CI 0.99-2.18, respectively). Similarly, the OR of the nondrinking group was higher than that of the drinking group (OR 2.70, 95% CI 1.46-4.99 and OR 1.48, 95% CI 1.01-2.17, respectively).

Conclusions

A positive correlation between solid fuel use and LUTS/BPH was observed. The results suggest that improving fuel structure for household cooking and other household needs can possibly help reduce the risk of LUTS/BPH.

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.

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.

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

Objective

This study investigates the associations and mediating pathways between grip strength, cognitive function, and depression in middle-aged and elderly individuals in China.

Methods

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.

Results

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]).

Conclusion

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.

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.

Multimorbidity, lifestyle, and cognitive function: A cross-cultural study on the role of diabetes, cardiovascular disease, cancer, and chronic respiratory diseases

BACKGROUND

The effect of lifestyle factors on cognitive function related to four major noncommunicable diseases (NCDs) including diabetes, cardiovascular disease, cancer, and chronic respiratory diseases, and the relationship between these NCDs and cognitive function have not been fully studied. We aimed to investigate the longitudinal associations between these NCDs and cognitive function in middle-aged and older people, and the combined effects of lifestyle factors.

METHODS

By employing the data from three large-scale cohort studies from the U.S. Health and Retirement Study (2010-2019), English Longitudinal Study of Aging (2014-2019), and China Health and Retirement Longitudinal Study (2011-2019), this study carried out a multi-cohort analysis to 77, 210 participants. Fixed-effects regression models were used to examine associations between NCD status and cognitive function. Margin plots were used to illustrate the effect of lifestyle factors.

RESULTS

Our findings revealed the dose-dependent association between mounting these NCDs and declining cognitive performance, ranging from one NCD (β = -0.05, 95 % CI: -0.08 to -0.02) to four NCDs (β = -0.51, 95 % CI: -0.75 to -0.28). Decline in cognitive function associated with NCDs was exacerbated with physical inactivity, current smoking status, and an increase in unhealthy lifestyle behaviors.

LIMITATIONS

The observational study design precludes causal interrogation of lifestyles and four NCDs on cognitive function.

CONCLUSIONS

An increasing number of these NCDs were dose-dependently associated with the decline in cognitive function score. Unhealthy lifestyle factors expedite decline in cognitive function linked to these NCDs.

Association between nighttime sleep duration, nap time, and mild cognitive impairment in Chinese older adults: a cross-sectional study

OBJECTIVE

This study aims to investigate the relationship between midday nap time, nighttime sleep duration, and mild cognitive impairment (MCI) in Chinese older adults and determine the recommended sleep duration to provide a scientific basis for preventing and managing MCI in this population.

METHODS

Utilizing the 2020 China Health and Retirement Longitudinal Study database, the demographic data, health status, and lifestyle information of the study participants were collected. A total of 5,314 valid samples were included in the analysis. Logistic regression and restricted cubic spline plots were employed to explore the relationship between sleep patterns and MCI.

RESULTS

In the cross-sectional analysis, a linear relationship was observed between midday nap duration and MCI among Chinese elderly. The probability of MCI was lowest among those who napped for less than 30 min at noon. Compared with individuals who napped for30-90 min, those who did not nap were more likely to have MCI (OR = 1.30, 95% CI: 1.05-1.60). Older adults with napping duration < 30 min (OR = 0.73, 95% CI:0.56-0.95) also exhibited lower probability of MCI when compared those without napping habit, Nighttime sleep duration exhibited a U-shaped relationship with MCI. Individuals with less than approximately 6 h of nighttime sleep showed a gradual decrease in the probability of MCI with increasing sleep duration, whereas those with more than 7.5 h demonstrated an increase in the probability of MCI with longer sleep duration. Older adults who slept less than 6 h at night (OR = 1.22, 95% CI: 1.01 ~ 1.46) or more than 8 h (OR = 1.78, 95% CI: 1.35-2.33) were more likely to develop MCI compared with those who slept 6 to 8 h.

CONCLUSION

After controlling for potential confounding variables, both nighttime sleep duration and midday nap duration exhibited a nonlinear "U"-shaped relationship with MCI among the elderly. The probability of depression was lower with a nap duration of approximately 60 min, and the optimal nighttime sleep duration was 6-8 h, with around 7 h providing the greatest cognitive benefits.

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.

The effects of fine particulate matter, solid fuel use and greenness on the risks of diabetes in middle-aged and older Chinese

BACKGROUND

Previous studies provided clues that environmental factors were closely related to diabetes incidence. However, the evidence from high-quality and large cohort studies about the effects of PM2.5, solid fuel use and greenness on the development of diabetes among middle-aged and older adults in China was scarce.

OBJECTIVE

To separately investigate the independent effects of PM2.5, solid fuel use and greenness on the development of diabetes among middle-aged and older adults.

METHODS

A total of 9242 participants were involved in this study extracted from the China Health and Retirement Longitudinal Study. Time-varying Cox regression was applied to detect the association of diabetes with PM2.5, solid fuel use and greenness, separately. The potential interactive effect of air pollution and greenness were explored using the relative excess risk due to interaction (RERI).

RESULTS

Per 10 μg/m3 increases in PM2.5 were associated with 6.0% (95% CI: 1.9, 10.2) increasing risks of diabetes incidence. Females seemed to be more susceptible to PM2.5. However, the effects of solid fuel use only existed in older and lower BMI populations, with hazard ratios (HRs) of 1.404 (1.116, 1.766) and 1.346 (1.057, 1.715), respectively. In addition, exposure to high-level greenness might reduce the risks of developing diabetes [HR = 0.801 (0.687, 0.934)]. Weak evidence of the interaction effect of PM2.5/solid fuel use and greenness on diabetes was found.

SIGNIFICANCE

Both PM2.5 and solid fuel use were associated with the increasing incidence of diabetes. In addition, high-level greenness might be a beneficial environmental factor for reducing the risks of developing diabetes. All in all, our findings might provide valuable references for public health apartments to formulate very fruitful policies to reduce the burden of diabetes.

IMPACT STATEMENT

Both PM2.5 and solid fuel use were associated with the increasing incidence of diabetes while high-level greenness was not, which might provide valuable references for public health apartments to make policies.

The impact of energy poverty on the health and welfare of the middle-aged and older adults

Drawing upon data from the 2018 CHARLS, this paper utilizes MEPI and a 10% threshold indicator to, respectively, assess the energy poverty (EP) status among middle-aged and older adults in China, focusing on the unavailability and unaffordability of energy services. Additionally, an econometric model is constructed to investigate the effects of EP on the health and welfare of middle-aged and older adults. Regression results indicate that EP exerts a significant negative impact on the health and welfare of middle-aged and older adults. This conclusion remains robust after conducting endogeneity and robustness tests, demonstrating its validity. Finally, based on the calculation results, we propose relevant policy recommendations including enhancing energy services for older adults in rural areas, integrating household energy alternatives with targeted poverty alleviation, enhancing monitoring mechanisms, and conducting energy education activities to alleviate EP and improve the quality of life of middle-aged and older adults.

The effect of childhood family adversity on adulthood depression among Chinese older migrant workers: gender differences in the mediating role of social-ecological systems

BACKGROUND

Older migrant workers (OMWs) in China face unique challenges rooted in their early life experiences, which increase their vulnerability to psychological and behavioral problems in adulthood. By utilizing the cumulative disadvantage model and the social-ecological systems theory, this study explored the effect of childhood family adversity on adulthood depression in the mediating roles of OMWs' social-ecological microsystem and mesosystem and further examined gender differences in these associations.

METHODS

Data were collected from the China Health and Retirement Longitudinal Study (CHARLS), involving a sample of 4,309 OMWs aged 50 and above. The measures included the Center for Epidemiological Research Depression Scale, childhood family adversity, socioeconomic status, marital quality, and physical and cognitive health.

RESULTS

Childhood family adversity was positively associated with adulthood depression among OMWs. Social microsystem (physical and cognitive health) and mesosystem (marital quality and socioeconomic status) factors significantly mediated this relationship. Multi-group analysis revealed that the mediating effects of marital quality and socioeconomic status were stronger for female OMWs, while the mediating effects of physical and cognitive health were stronger for male OMWs.

CONCLUSIONS

The findings suggest that childhood family adversity has a lasting impact on the mental health of OMWs, and that social-ecological systems factors play an important role in this relationship. The study also highlights the need for gender-specific interventions to address the mental health needs of OMWs.

Sleep duration and leisure activities are involved in regulating the association of depressive symptoms, muscle strength, physical function and mild cognitive impairment

Background

In order to lessen the burden of Alzheimer's disease (AD), timely and efficient management and intervention methods for mild cognitive impairment (MCI) are crucial. MCI is seen as a transitional stage between normal aging and dementia. Although sarcopenia is an important risk factor for MCI, it is unclear what factors mediates and regulates the brain-muscle communication. Our objective was to investigate the indirect moderating effects of sleep duration and leisure activity on depressive symptoms, sarcopenia and MCI.

Method

Panel data from the 2015 China Health and Retirement Longitudinal Study (CHARLS) database was used in this investigation. we used Bootstrap sampling to determine the relationship between sleep duration, leisure activity, depressive symptoms, sarcopenia, and MCI in mediation and indirect moderation models. The outcome measurements were odds ratio (OR) and confidence interval (CI).

Result

After adjusting for confounding variables, we discovered that sarcopenia and its traits, such as handgrip strength, gait speed, standing test, and muscle mass, were significantly correlated with MCI. Second, the results implied that depressive symptoms played a role in modulating the link between physical function, muscle strength, and MCI. This moderating effect was impacted by short sleep duration and moderate to high levels of leisure activities.

Conclusion

We discovered that MCI was highly correlated not only with physical function and muscle strength but also with depressed symptoms, which acted as a partially mediating factor in this connection. Handgrip strength, gait speed, and standing test mediated the correction of MCI caused by depression symptoms. Importantly, leisure activities and sleep duration had indirect moderating effects on the above associations, and future management policies should take these factors into account.

Household Environments and Cognitive Decline Among Middle-Aged and Older Adults in China: Exploring Gender, Age, and Residential Variations

This study examined the relationship between household environments and trajectories of cognitive function among middle-aged and older adults in China and its urban/rural, gender, and age variations. We estimated multi-level linear growth curve models using a representative sample of 16,111 respondents aged 45 years and over from the China Health and Retirement Longitudinal Study (2011-2018). Older people who lived with a spouse, but not with children, and those with higher living expenditures, better housing quality, and indoor clean fuels for cooking had a slower cognitive decline. Living arrangement more strongly predicted men's cognitive decline, while living expenditure, solid fuel use, and housing quality significantly predicted only women's cognitive decline. Only for older adults and rural residents, those living alone had significantly faster cognitive decline than those living with a spouse only. These findings underscore the importance of improving the living conditions of older adults to help alleviate their cognitive decline.

Effects of indoor air pollution from household solid fuel use on the risk of gastrointestinal and liver diseases in middle aged and elderly adults

Solid fuels are widely used in China and increase the concentrations of indoor air pollutants. Nevertheless, there is limited longitudinal evidence linking solid fuel use and Gastrointestinal (GI) and liver diseases. This study aimed to prospectively investigate the association between household solid fuel use and the risk of GI and liver diseases in middle aged and elderly adults. This work was based on the China Health and Retirement Longitudinal Study (CHARLS). Longitudinal data incorporate with cross-sectional data were analyzed. Compared with individuals using clean fuel for cooking, solid fuel users were observed to have higher risk of GI diseases (OR in 2011, 2013, 2015, 2018 wave separately: 1.37, 95 % CI: 1.24-1.50, P < 0.001; 1.24, 95 % CI: 1.11-1.39, P < 0.001; 1.18, 95 % CI: 1.06-1.33, P < 0.001; 1.23, 95 % CI: 1.04-1.45, P < 0.05). The associations between solid fuel use and liver diseases were not significant in most of the groups. Participants transforming from solid to clean cooking fuels had lower risk of GI and liver diseases than persistent solid fuel users. Moreover, biomass cooking fuel users were at a significant higher risk of both liver and GI diseases compared with clean fuel users. Overall, household solid fuel use, especially for cooking, was related to higher risk of GI and liver diseases, while switching from solid to clean fuels could reduce this risk. Using biomass for cooking was identified to be more associated with the increasing risk of GI and liver diseases than cooking with coal.

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.

Association between indoor air pollution and depression: a systematic review and meta-analysis of cohort studies

OBJECTIVES

Incomplete combustion of solid fuel and exposure to secondhand smoke (SHS) are the primary causes of indoor air pollution (IAP), potentially leading to detrimental effects on individual mental health. However, current evidence regarding the association between IAP and depression remains inconclusive. This study aims to systematically investigate the evidence regarding the association between IAP and the risk of depression.

DESIGN

Systematic review and meta-analysis of cohort studies.

DATA SOURCES

Two independent reviewers searched PubMed, the Cochrane Library, Web of Science and EMBASE for available studies published up to 13 January 2024.

ELIGIBILITY CRITERIA

We included all cohort studies published in English that aimed to explore the relationship between IAP from solid fuel use and SHS exposure and the risk of depression.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed the risk of bias. The association between IAP and depression was calculated using pooled relative risk (RR) with 95% CIs. Heterogeneity was assessed using the I2 value, and the effect estimates were pooled using fixed-effects or random-effects models depending on the results of homogeneity analysis.

RESULTS

We included 12 articles with data from 61 217 participants. The overall findings demonstrated a significant association between IAP exposure and depression (RR=1.22, 95% CI: 1.13 to 1.31), although with substantial heterogeneity (I2=75%). Subgroup analyses based on pollutant type revealed that IAP from solid fuel use was associated with a higher risk of depression (RR=1.20, 95% CI: 1.13 to 1.26; I2=62%; 5 studies, 36 768 participants) than that from SHS exposure (RR=1.11, 95% CI: 0.87 to 1.41; I2=80%; 7 studies, 24 449 participants). In terms of fuel use, the use of solid fuel for cooking (RR: 1.23, 95% CI: 1.16 to 1.31; I2=58%; 4 studies, 34 044 participants) and heating (RR 1.15, 95% CI: 1.04 to 1.27; I2=65%; 3 studies, 24 874 participants) was associated with increased depression risk.

CONCLUSIONS

The findings from this systematic review and meta-analysis of cohort studies indicated an association between exposure to IAP and depression.

PROSPERO REGISTRATION NUMBER

CRD42022383285.

An analysis of factors influencing cognitive dysfunction among older adults in Northwest China based on logistic regression and decision tree modelling

BACKGROUND

Cognitive dysfunction is one of the leading causes of disability and dependence in older adults and is a major economic burden on the public health system. The aim of this study was to investigate the risk factors for cognitive dysfunction and their predictive value in older adults in Northwest China.

METHODS

A cross-sectional study was conducted using a multistage sampling method. The questionnaires were distributed through the Elderly Disability Monitoring Platform to older adults aged 60 years and above in Northwest China, who were divided into cognitive dysfunction and normal cognitive function groups. In addition to univariate analyses, logistic regression and decision tree modelling were used to construct a model to identify factors that can predict the occurrence of cognitive dysfunction in older adults.

RESULTS

A total of 12,494 valid questionnaires were collected, including 2617 from participants in the cognitive dysfunction group and 9877 from participants in the normal cognitive function group. Univariate analysis revealed that ethnicity, BMI, age, educational attainment, marital status, type of residence, residency status, current work status, main economic source, type of chronic disease, long-term use of medication, alcohol consumption, participation in social activities, exercise status, social support, total scores on the Balanced Test Assessment, total scores on the Gait Speed Assessment total score, and activities of daily living (ADL) were significantly different between the two groups (all P < 0.05). According to logistic regression analyses, ethnicity, BMI, educational attainment, marital status, residency, main source of income, chronic diseases, annual medical examination, alcohol consumption, exercise status, total scores on the Balanced Test Assessment, and activities of daily living (ADLs) were found to influence cognitive dysfunction in older adults (all P < 0.05). In the decision tree model, the ability to perform activities of daily living was the root node, followed by total scores on the Balanced Test Assessment, marital status, educational attainment, age, annual medical examination, and ethnicity.

CONCLUSIONS

Traditional risk factors (including BMI, literacy, and alcohol consumption) and potentially modifiable risk factors (including balance function, ability to care for oneself in daily life, and widowhood) have a significant impact on the increased risk of cognitive dysfunction in older adults in Northwest China. The use of decision tree models can help health care workers better assess cognitive function in older adults and develop personalized interventions. Further research could help to gain insight into the mechanisms of cognitive dysfunction and provide new avenues for prevention and intervention.

Household use of solid fuel and sarcopenia among middle-aged and older adults: The China Health and Retirement Longitudinal Study

OBJECTIVE

Few studies have examined the effects of air pollution on the risk of sarcopenia, especially pollution in indoor settings. We explored the cross-sectional and longitudinal associations of household use of solid fuel for cooking and heating, separately and simultaneously, with risk of sarcopenia.

METHODS

Cross-sectional and follow-up data from the China Health and Retirement Longitudinal Study were used. Multivariable-adjusted generalized linear models and Cox proportional hazards regression models were performed to estimate the odds ratio and hazard ratio for sarcopenia, respectively.

RESULTS

11,494 (median age: 57.0 years; 47.4 % males) and 7483 (median age: 57.0 years; 46.9 % males) participants were included in the cross-sectional and longitudinal study, respectively. After fully adjusting for covariates, including outdoor concentration of particulate matter (PM2.5), both the use of solid fuels for cooking and use for heating were positively associated with incident sarcopenia in the longitudinal analyses, with hazard ratios (95 % confidence interval) of 1.56 (1.28-1.89) and 1.26 (1.04-1.52), respectively. Moreover, significant multiplicative and/or additive interactions were observed between age, smoking and cooking with solid fuel and risk of sarcopenia (all P for interaction <0.05). Similar results were found in the cross-sectional analyses.

CONCLUSIONS

Household use of solid fuel was significantly associated with a higher risk of sarcopenia, while ageing and smoking had synergetic effects with burning solid fuels on the risk of sarcopenia. Our results highlight the importance of taking multi-pronged measures with respect to both air pollution and healthy lifestyle to prevent sarcopenia and promote healthy ageing.

Exploring relevant factors of cognitive impairment in the elderly Chinese population using Lasso regression and Bayesian networks

Older adults are highly susceptible to developing cognitive impairment(CI). Various factors contribute to the prevalence of CI, but the potential relationships among these factors remain unclear. This study aims to explore the relevant factors associated with CI in Chinese older adults and analyze the potential relationships between CI and these factors.We analyzed the data on 6886 older adults aged≥60 from the China Health and Retirement Longitudinal Study (CHARLS) 2018. Lasso regression was initially used to screening variables. Bayesian Networks(BNs) were used to identify the correlates of CI and potential associations between factors. After screening with Lasso regression, 11 variables were finally included in the BNs. The BNs, by establishing a complex network relationship, revealed that age, education, and indoor air pollution were the direct correlates affecting the occurrence of CI in older adults. It also indicated that marital status indirectly influenced CI through age, and residence indirectly linked to CI through two pathways: indoor air pollution and education.Our findings underscore the effectiveness of BNs in unveiling the intricate network linkages among CI and its associated factors, holding promising applications. It can serve as a reference for public health departments to address the prevention of CI in the elderly.

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.

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.

Association between solid cooking fuel use and dementia in older Chinese adults: the mediating effect of depression

This study aimed to explore the association between household solid cooking fuel use and dementia prevalence and the mediating effect of depression on this association. A total of 3404 (2018) and 1379 (2015 to 2018) older participants (≥65) from the China Health and Retirement Longitudinal Study (CHARLS) were enrolled in the cross-sectional and retrospective longitudinal analyses, respectively. The results showed that solid cooking fuel use was associated with an increased dementia prevalence (adjusted OR = 1.44) from 2015 to 2018. The indirect effect of depression on this association explained 7.14% and 13.11% variances in the cross-sectional and longitudinal mediating model, respectively. Thus, household solid cooking fuel use is a risk factor for the development of dementia, and depressive symptoms partially accounted for this association. The use of improved cookstoves and clean fuel in households and air cleaners and early intervention in depression may reduce the incidence of dementia.

Prevalence and correlates of disability in older adults, Ghana: evidence from the Ghana 2021 Population and Housing Census

BACKGROUND

Although there are studies on disabilities in older persons, most of these studies have been carried out in developed countries. Hence, there are limited studies on disability in older adults in sub-Saharan Africa, including Ghana. The few studies that have examined the prevalence and correlates of disability in older adults used survey data for their analyses. To contribute to addressing this knowledge gap that has arisen, this study used a national census, the 2021 Ghana Population and Housing Census, to examine the prevalence and correlates of disability in older adults in Ghana.

METHODS

The 2021 Ghana Population and Housing Census data was used for this study. A sample size of 197,057 Ghanaians aged 60 years and above was used for this study. The Washington Group questions on disability were used to measure disability by asking older adults about their difficulties in performing the six domains of disability (physical, sight, intellectual, hearing, self-care, and speech). A multinomial logistic regression housed in STATA was used to analyse the correlates of disability in older adults in Ghana. A p-value less than 0.05 was used for statistical significance.

RESULTS

The results show that slightly more than one-third (38.4%) of the older adults were disabled. In terms of the number of disabilities in older adults, 16.9% had one disability condition, while 2.4% had six disability conditions. Also, 9.4% had two disability conditions. Older adults who were females, aged 70-79 years and 80 years and above, resided in rural areas, with primary, JHS/Middle, SHS, unaffiliated with religion, ever married and never married, unemployed, and belonged to the middle and rich households were more likely to have a disability condition. Also, older adults residing in the Middle and Northern zones, having no health insurance, and using clean cooking fuel were less likely to have a disability condition.

CONCLUSIONS

The results show that socio-demographic and household factors were associated with disability in older adults in Ghana. Hence, policymakers and researchers should target these factors when designing appropriate policies, programmes, and interventions to improve the wellbeing of older adults.

The association between outdoor air pollution and body mass index, central obesity, and visceral adiposity index among middle-aged and elderly adults: a nationwide study in China

Background

Previous animal studies have suggested that air pollution (AP) exposure may be a potential risk factor for obesity; however, there is limited epidemiological evidence available to describe the association of obesity with AP exposure.

Methods

A retrospective cross-sectional study was conducted on 11,766 participants across mainland China in 2015. Obesity was assessed using body mass index (BMI), waist circumference (WC), and visceral adiposity index (VAI). The space-time extremely randomized tree (STET) model was used to estimate the concentration of air pollutants, including SO2, NO2, O3, PM1, PM2.5, and PM10, matched to participants' residential addresses. Logistic regression models were employed to estimate the associations of obesity with outdoor AP exposure. Further stratified analysis was conducted to evaluate whether sociodemographics or lifestyles modified the effects.

Results

Increased AP exposure was statistically associated with increased odds of obesity. The odds ratio (ORs) and 95% confidence interval (CI) of BMI-defined obesity were 1.21 (1.17, 1.26) for SO2, 1.33 (1.26, 1.40) for NO2, 1.15 (1.10, 1.21) for O3, 1.38 (1.29, 1.48) for PM1, 1.19 (1.15, 1.22) for PM2.5, and 1.11 (1.09, 1.13) for PM10 per 10 μg/m3 increase in concentration. Similar results were found for central obesity. Stratified analyses suggested that elderly participants experienced more adverse effects from all 6 air pollutants than middle-aged participants. Furthermore, notable multiplicative interactions were found between O3 exposure and females as well as second-hand smokers in BMI-defined obesity.

Conclusions

This study suggested that outdoor AP exposure had a significant association with the risk of obesity in the middle-aged and elderly Chinese population. Elderly individuals and women may be more vulnerable to AP exposure.

Associations between indoor air pollution for cooking and heating with muscle and sarcopenia in Chinese older population

BACKGROUND

Exposure to air pollution brings the advent effect for various diseases, but study about the relationship between air pollution and ageing is scant. We aimed to determine the associations between household air pollution for cooking and heating with muscle and sarcopenia in Chinese older population by a nationally representative study.

METHODS

This cross-sectional study included individuals aged 60 and above from the China Health and Retirement Longitudinal Study between 2011 and 2015. The diagnosis of sarcopenia was defined by low muscle mass with low muscle strength and/or reduced physical performance. Generalized additive analyses and dose-dependent analyses with three models were used to assess the effects of different pattern of cooking and heating on muscle and sarcopenia.

RESULTS

A total of 8126 Chinese older individuals with predominant male (53.7%) and mean age of 67.3 ± 6.0 years were included in our study. Solid fuel use in cooking showed significant declines in muscle strength (β = -0.424, 95% CI: -0.767, -0.082, P = 0.01 in model 3) and mass (β = -0.034, 95% CI: -0.051, -0.017, P < 0.01 in model 3), when compared with clean fuel use in cooking, respectively. Solid fuel for heating was correlated with lower muscle strength (β = -0.637, 95% CI: -1.033, -0.241, P < 0.01 in model 3) than clean fuel for heating. The joint use of solid fuel for cooking and heating was associated with reduced muscle strength (β = -0.835, 95% CI: -1.306, -0.365, P < 0.01 in model 3) and mass (β = -0.038, 95% CI: -0.061, -0.015, P < 0.01 in model 3) than clean fuel for cooking and heating. Solid fuel for cooking was associated with significantly increased risk of low muscle strength (adjusted OR = 1.29, 95% CI: 1.11, 1.50, P < 0.01 in model 3) and mass (adjusted OR = 1.35, 95% CI: 1.11, 1.61, P < 0.01 in model 3), possible sarcopenia (adjusted OR = 1.33, 95% CI: 1.19, 1.48, P < 0.01 in model 3) and sarcopenia (adjusted OR = 1.44, 95% CI: 1.21, 1.72, P < 0.01 in model 3) compared with clean fuel for cooking. Solid fuel for heating had a significant correlation with low muscle strength (adjusted OR = 1.30, 95% CI: 1.09, 1.56, P < 0.01 in model 3) and possible sarcopenia (adjusted OR = 1.49, 95% CI: 1.31, 1.70, P < 0.01 in model 3). Dose-dependent manner was shown in the associations between the number of solid fuel with low muscle strength and possible sarcopenia. Clean fuel for cooking and solid fuel for heating was positively associated with the prevalence of possible sarcopenia than clean fuel for cooking and heating (adjusted OR = 1.34, 95% CI: 1.14, 1.57, P < 0.01 in model 3).

CONCLUSIONS

Our findings suggested that solid fuel for cooking and the number of solid fuel use potentially facilitates the onset and progression of muscle loss and sarcopenia.

The Association Between Solid Fuel Use and Visual Impairment Among Middle-Aged and Older Chinese Adults: Nationwide Population-Based Cohort Study

BACKGROUND

Indoor air pollution has been reported to have adverse effects on the eye; however, the health effects of exposure to cooking with solid fuels on visual impairment remain unclear in China.

OBJECTIVE

We aimed to examine the association between cooking with solid fuels and visual impairment, including distance visual impairment (DVI) and near visual impairment (NVI).

METHODS

Data were obtained from the China Health and Retirement Longitudinal Study, a nationwide survey of adults aged over 45 years who were enrolled in 2011 (Wave 1) and followed up in Wave 2 (2013), Wave 3 (2015), and Wave 4 (2018). We used Cox proportional hazards models to determine the association between solid fuels use and visual impairment. Additionally, the impact of switching cooking fuel types on vision function were examined through wave-specific data analysis (Wave 1 and Wave 4). Interaction and subgroup analyses were performed to explore the potential effect modifiers. Data were collected using the stratified multistage random sampling method and further analyzed using SPSS 27.0 and R 4.2.1 statistical software packages.

RESULTS

A total of 9559 middle-aged and older Chinese adults without visual impairment at baseline were included in the study, with 51.2% (n=4914) of the participants reporting that they cooked with solid fuels. During the follow-up period, 2644 (27.5%) and 3130 (32.6%) participants developed DVI and NVI, respectively. Compared with the clean fuel users, participants who cooked with solid fuels had a higher risk of DVI (hazards ratio [HR] 1.38, 95% CI 1.28-1.50) and NVI (HR 1.18, 95% CI 1.10-1.27). In addition, switching the cooking fuel type from clean to solid fuels was associated with an elevated risk of DVI (HR 1.51, 95% CI 1.15-1.98) and NVI (HR 1.39, 95% CI 1.06-1.82) compared to persistently using clean fuels during the follow-up period, although no protective effect of switching from solid to clean fuels on NVI was found (P=.52). In subgroup analysis, we found that cooking with solid fuels increased the risk of DVI in participants younger than 65 years (HR 1.41, 95% CI 1.28-1.55), men (HR 1.45, 95% CI 1.28-1.65), urban residents (HR 1.41, 95% CI 1.08-1.75), and smokers (HR 1.43, 95% CI 1.25-1.64). By contrast, negative effects of cooking with solid fuels on NVI were found in nonsmokers (HR 1.21, 95% CI 1.11-1.33) and urban residents (HR 1.20, 95% CI 1.10-1.37).

CONCLUSIONS

Cooking with solid fuels was associated with an increased risk of visual impairment among middle-aged and older Chinese adults. These findings indicate that promoting the utilization of clean fuels is conducive to reducing the burden of visual impairment for the public.

Predictor of cognitive impairment: metabolic syndrome or circadian syndrome

BACKGROUND

It was reported that metabolic syndrome increases the risk for cognitive impairment and circadian rhythm may influence cognition behavior. Identifying the potential risk factors is essential to screen individuals with neuronal dysfunction, neuronal loss, and cognitive decline and prevent cognitive impairment and dementia development.

METHODS

We clarified participants by the presence of metabolic syndrome (MetS) and circadian syndrome (CircS) and employed three multivariable Generalized Estimating Equation (GEE) models to control the potential confounding factors and estimate the β values for cognitive function using as referents those had neither MetS nor CircS at baseline. The cognitive function consists of episodic memory and executive function was estimated via the modified Telephone Interview for Cognitive Status (TICS) every two years until 2015.

RESULTS

The mean age of the participants was 58.80 (8.93) years and 49.92% (male). The prevalence of MetS and CircS was 42.98% and 36.43%, respectively. 1,075 (11.00%) and 435 (4.45%) participants had either MetS or CircS alone and 3,124 (31.98%) had both CircS and MetS. Participants with both MetS and CircS compared with normal had a significantly decreased cognitive function score during the 4-years cohort (β = -0.32, 95% CI: -0.63, -0.01) with the complete model, as well as among participants who suffered from CircS alone (β = -0.82, 95% CI: -1.47, -0.16), while not among participants with MetS alone (β = 0.13, 95% CI: -0.27, 0.53). Specifically, compared with the normal population a significantly lower score was discovered in the episodic memory (β = -0.51, 95% CI: -0.95, -0.07), while slightly lower in executive function (β = -0.33, 95% CI: -0.68, -0.01) among individuals with CircS alone.

CONCLUSIONS

Individuals with CircS alone or both MetS and CircS have a high risk of cognitive impairment. The association was even stronger in participants with CircS alone than those with both MetS and CircS, suggesting CircS probably have a stronger association with cognitive functioning than MetS and could be a better predictor for cognitive impairment.

Associations between cooking fuels and hypertension prevalence in Chinese adults: A prospective cohort analysis focusing on fuel transitioning

BACKGROUND

Using polluting cooking fuels is a suggested risk factor for hypertension. Transitioning to clean cooking fuels has occurred widely in China in the past 30 years. This provides an opportunity to examine whether the transition could reduce hypertension risk and to ascertain the inconsistent literature on the relationship between cooking fuels and hypertension prevalence.

METHODS

Initiated in 1989, the China Health and Nutrition Survey (CHNS) enrolled participants from 12 provinces in China. By 2015, nine waves of follow-up have been conducted. Based on self-reported cooking fuels, participants were classified into persistent clean fuel users, persistent polluting fuel users and those who transitioned from polluting fuels to clean fuels. Hypertension was defined as having systolic blood pressure (SBP) ≥ 140 mmHg, diastolic blood pressure (DBP) ≥ 90 mmHg, or self-reported current use of antihypertension medication.

FINDINGS

Among 12,668 participants, 3963 (31.28%) were persistent polluting fuel users; 4299 (33.94%) transitioned to clean fuels; and 4406 (34.78%) were persistent clean fuel users. During the period of follow-up (7.8 ± 6.1 years), hypertension was diagnosed in 4428 participants. Compared to persistent clean fuel users, persistent polluting fuel users had a higher risk for hypertension (hazard ratio [HR] 1.69, 95%CI 1.55-1.85), while those transitioned to clean fuels did not. The effects were consistent by gender and urbanicity, respectively. The HRs for hypertension were 1.99 (95%CI 1.75-2.25), 1.55 (95%CI 1.32-1.81) and 1.36 (95%CI 1.13-1.65) among those persistent polluting fuel users aged 18-44, 45-59 and ≥60 years old, respectively.

INTERPRETATION

Transitioning from using polluting fuels to clean fuels prevented an increase in hypertension risk. The finding highlights the importance of promoting the fuel transition as a risk-reduction strategy for reducing the disease burden from hypertension.

Butyl benzyl phthalate as a key component of phthalate ester in relation to cognitive impairment in NHANES elderly individuals and experimental mice

Phthalates are a group of neurotoxicants with cognitive-disrupting potentials. Given the structural diversity of phthalates, the corresponding neurotoxicity is dramatically altered. To identify the potential contributions of different phthalates on the process of cognitive impairment, data of 836 elders from the NHANES 2011-2014 cycles were used. Survey-weighted logistic regression and principal component analysis-weighted quantile sum regression (PCA-WQSR) models were applied to estimate the independent and combined associations of 11 urinary phthalate metabolites with cognitive deficit (assessed by 4 tests: Immediate Recall (IR), Delayed Recall (DR), Animal Fluency (AF), and Digit Symbol Substitution Test (DSST)) and to identify the potential phthalate with high weight. Laboratory mice were further used to examine the effect of phthalates on cognitive function and to explore the potential mechanisms. In logistic regression models, MBzP was the only metabolite positively correlated with four tests, with ORs of 2.53 (quartile 3 (Q3)), 2.26 (Q3), 2.89 (Q4) and 2.45 (Q2), 2.82 (Q4) for IR, DR, AF, and DSST respectively. In PCA-WQSR co-exposure models, low-molecular-weight (LMW) phthalates were the only PC positively linked to DSST deficit (OR: 1.93), which was further validated in WQSR analysis (WQS OR7-phthalates: 1.56 and WQS OR8-phthalates: 1.55); consistent with the results of logistic regression, MBzP was the dominant phthalate. In mice, butyl benzyl phthalate (BBP), the parent phthalate of MBzP, dose-dependently reduced cognitive function and disrupted hippocampal neurons. Additionally, the hippocampal transcriptome analysis identified 431 differential expression genes, among which most were involved in inhibiting the neuroactive ligand-receptor interaction pathway and activating the cytokine-cytokine receptor interaction pathway. Our study indicates the critical role of BBP in the association of phthalates and cognitive deficits among elderly individuals, which might be speculated that BBP could disrupt hippocampal neurons, activate neuroinflammation, and inhibit neuroactive receptors. Our findings provide new insight into the cognitive-disrupting potential of BBP.

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

BACKGROUND

Household solid-fuel burning contributes to indoor air pollution and is linked to poor cognitive function, but how solid cooking fuel use leads to cognitive decline over time is not well elaborated.

OBJECTIVE

We examine the associations of solid cooking fuel with cognitive function among three nationally representative cohorts.

METHODS

This study uses data from the 2010-2018 China Family Panel Studies (CFPS), the 2011-2018 China Health and Retirement Longitudinal Study (CHARLS) and the 2003-2015 Mexican Health and Aging Study (MHAS) in adults over the age of 50. Time varying Cox model was conducted to measure the association between cooking fuel types and cognitive decline. Mediation analysis was used to estimate the potential mediation effects on the associations of cooking fuel types with cognitive decline risk.

RESULTS

Respondents in CFPS, CHARLS, and MHAS relied on solid cooking fuel at baseline approximately 56 %, 51 %, and 12 %, respectively. Using solid fuel was consistently associated with higher risk of cognitive decline in three cohorts (CFPS: HR = 1.300 [95 % CI: 1.201, 1.407], CHARLS: HR = 1.179 [95 % CI: 1.059, 1.312], MHAS: HR = 1.237 [95 % CI: 1.123, 1.362]). Compared to those with persistent solid fuel, persistent clean fuel and change from solid fuel to clean fuel were associated with a lower risk of cognitive decline. Hypertension, diabetes, physical activity, dyslipidemia and high-density lipoprotein cholesterol (HDL-C) may partially mediate the cognitive decline caused by solid fuel use. Of the cognitive decline burden, 18.23 % (95 % CI: 12.21 %, 24.73 %) in CFPS, 8.90 % (95 % CI: 2.93 %, 15.52 %) in CHARLS and 2.92 % (95 % CI: 1.52 %, 4.46 %) in MHAS of cognitive decline cases attributable to solid cooking fuel use.

CONCLUSION

The use of solid cooking fuel is associated with a higher risk of cognitive decline. It is essential to promote the expanded use of clean fuel to protect cognitive health.

The increased medical burden associated with frailty is partly attributable to household solid fuel: A nationwide prospective study of middle-aged and older people in China

BACKGROUND

Frail individuals often face a high medical burden, and household solid fuel use is associated with a range of functional declines or diseases, but evidence on the relationship between household solid fuel and frailty and the resulting medical burden is limited. We aim to investigate the effect of household solid fuel on frailty and further quantify how much of the increased medical burden associated with frailty is attributable to household solid fuel.

METHODS

The prospective data were from the China Health and Retirement Longitudinal Study, 4685 non-frail participants at baseline were included. Inverse probability weighting was used to balance the covariates between groups. The modified Poisson regression was used to analyze the association of household solid fuel (including baseline and switching across three-wave survey) with frailty, and the generalized linear model was used to analyze the association of frailty with the change in medical burden. Further, the increased medical burden associated with frailty attributable to household solid fuel was quantified.

RESULTS

Using solid fuel for cooking (RR = 1.29, 95%CI, 1.07-1.57), heating (RR = 1.38, 95%CI, 1.09-1.73), or both (RR = 1.40, 95%CI, 1.05-1.86) had a higher risk of frailty than using clean fuel. In addition, the risk of frailty generally increases with the times of solid fuel use across the three-wave survey. Then, frailty participants had a greater increase in the annual number of hospitalizations (β = 0.11, 95%CI, 0.02-0.19) and annual costs of hospitalizations (β = 2953.35, 95%CI, 1149.87-4756.83) than those non-frailty. Heating coal caused the largest frailty-related increase in the annual number of hospitalizations and annual costs of hospitalizations, with 0.04 and 1195.40, respectively.

CONCLUSION

The increased medical burden associated with frailty was partly attributable to household solid fuel, which suggested that intervention targeting household solid fuels can delay frailty and thus reduce individual medical burden.

Association of solid fuel use with a risk score capturing dementia risk among middle-aged and older adults: A prospective cohort study

OBJECTIVES

Whether household air pollution is associated with dementia risk remains unknown. This study examined the associations between solid fuel use for cooking and heating (the main source of household air pollution) and dementia risk.

METHODS

This analysis included data on 11,352 participants (aged 45+ years) from the 2011 wave of China Health and Retirement Longitudinal Study, with follow-up to 2018. Dementia risk was assessed by a risk score using the Rotterdam Study Basic Dementia Risk Model (BDRM), which was subsequently standardized for analysis. Household fuel types of cooking and heating were categorized as solid (e.g., coal and crop residue) and clean (e.g., central heating and solar). Multivariable analyses were performed using generalized estimating equations. Moreover, we examined the joint associations of solid fuel use for cooking and heating with the BDRM score.

RESULTS

After adjusting for potential confounders, we found an independent and significant association of solid (vs. clean) fuel use for cooking and heating with a higher BDRM score (e.g., β = 0.17 for solid fuel for cooking; 95% confidence interval [CI]: 0.15-0.19). Participants who used solid (vs. clean) fuel for both cooking and heating had the highest BDRM score (β = 0.32; 95% CI: 0.29-0.36). Subgroup analysis suggested stronger associations in participants living in rural areas.

CONCLUSIONS

Solid fuel use for cooking and heating was independently associated with increased dementia risk in Chinese middle-aged and older adults, particularly among those living in rural areas. Our findings call for more efforts to facilitate universal access to clean energy for dementia prevention.

Household air pollution, adherence to a healthy lifestyle, and risk of cardiometabolic multimorbidity: Results from the China health and retirement longitudinal study

BACKGROUND

The adverse health effects of household air pollution have been widely explored, but few studies have evaluated the effects of household air pollution on the risk of cardiometabolic multimorbidity (CMM), a pressing public health concern worldwide. Thus, we aimed to investigate whether exposure to household use of polluting fuels is associated with morbid CMM and, if so, whether a healthy lifestyle could mitigate this association.

METHODS

In this prospective, nationwide representative cohort of the China Health and Retirement Longitudinal Study (CHARLS), participants free of CMM (defined as the coexistence of 2 or more of the following: heart disease, stroke, and diabetes or high blood sugar) were included in 2011-2012 and followed for CMM incidence until 2018. Household air pollution was measured as the use of solid fuels for cooking and heating. The healthy lifestyle score was determined by six factors, physical activity, smoking, body mass index, total cholesterol, blood glucose, and blood pressure, and categorized into three groups (unhealthy, 0-1 factors; intermediate, 2-4; and healthy, 5-6). Cox proportional hazards models investigated associations between household air pollution and incident CMM. The potential modifier effect of a healthy lifestyle score was tested through stratified analyses.

RESULTS

Among 7125 eligible participants, 239 incident cases of CMM were identified over a median follow-up of 7.0 years. After adjustment for potential confounders, the use of solid household fuels for heating was associated with more significant hazards of CMM (adjusted hazard ratio [HR] 1.71, 95 % confidence interval [CI] 1.28 to 2.28), while use for cooking (HR, 1.14; 95 % CI, 0.85 to 1.52) was not. Compared with participants in the unhealthy group, those in the healthy and intermediate groups had considerably lower CMM risk, with adjusted HRs (95 % CI) of 0.17 (0.09 to 0.31) and 0.39 (0.29 to 0.53), respectively, regardless of the household air pollution category. Importantly, when participants adhered to a healthy lifestyle, exposure to household air pollution was no longer significantly associated with a higher risk of CMM (adjusted HR 1.77, 95 % CI 0.51 to 6.12; P = 0.369).

CONCLUSIONS

Household usage of polluting fuels was significantly associated with a higher risk of CMM, and adherence to a healthy lifestyle may mitigate this adverse effect. From a broader perspective, our findings underscore the importance of public health policies and interventions targeting multiple exposures (air pollution, physical activity, smoking, etc.) in enhancing the prevention of detrimental cardiometabolic health effect.

Solid Fuel Use and the Progression of Multimorbidity in Middle-Aged Chinese Participants: A Prospective Cohort Study

Objectives: This study aimed to examine the association of solid fuel use for cooking and heating with the progression of multimorbidity. Methods: A total of 5,437 participants from the China Health and Retirement Longitudinal Study were included. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of the independent and joint effects of solid fuel use for cooking and heating with the progression of multimorbidity. Results: The proportion of participants reporting solid fuel use for both cooking and heating was 59.0% at baseline. Solid fuel use for both cooking and heating was associated with the progression of multimorbidity (adjusted OR: 1.42, 95% CI: 1.19-1.70), compared with clean fuel use for both. Conclusion: Solid fuel use for cooking and heating play an important role in the progression of multimorbidity. Therefore, solid fuel reduction should be considered in developing multimorbidity control and prevention programmes.

Associations of Household Solid Fuel Use With Falls and Fall-Related Injuries in Middle-Aged and Older Population in China: A Cohort Study

Objective: This study evaluated the associations of solid fuels with incidence of falls and fall-related injuries. Methods: Data were taken from wave 1∼4 of the China Health and Retirement Longitudinal Study, including 15,651 participants aged 45 years and older. Modified Poisson regression was used to examine the associations of solid fuels with falls and fall-related injuries. Results: Modified Poisson regression analysis showed that solid fuels users for cooking had an increasing incidence of falls and fall-related injuries, with RR of 1.211 (95% CI: 1.124, 1.305) and 1.248 (95% CI: 1.107, 1.408); for heating had an incidence, with RR of 1.178 (95% CI: 1.062, 1.306) and 1.134 (95% CI: 0.963, 1.335); combined for cooking and heating, with RR of 1.247 (95% CI: 1.105, 1.408) and 1.185 (95% CI: 0.982, 1.431). Conclusion: Our study suggests that solid fuel use is associated with a higher incidence of falls and fall-related injuries among adults aged 45 years and older in China. It is necessary to restrict solid fuel use to reduce household air pollution and make stronger environmental protection policies to improve household environment.

Association between daytime napping and cognitive impairment among Chinese older population: a cross-sectional study

BACKGROUND

Both napping and nighttime sleep duration have been reported to be associated with cognitive function in older adults, whereas little is known about the association between daytime napping and cognitive impairment in different nighttime sleep duration subgroups. This study aimed to explore the correlation between daytime napping and cognitive impairment across nighttime sleep duration subgroups.

METHODS

A cross-sectional study was conducted by using the fourth survey of China Health and Retirement Longitudinal Study (CHARLS). We utilized the Mini-Mental State Examination (MMSE) scale to define cognitive impairment, and the daytime napping and nighttime sleep duration was self-reported by individuals. We applied the Restricted Cubic Spline (RCS) to analysis the dose-response relationships between daytime napping and cognitive impairment. And the multivariate Logistic Regression Model (LRM) was performed to evaluate the association of daytime napping and cognitive impairment.

RESULTS

A total of 3,052 individuals were included, of which 769 were cognitive impairment. The RCS showed there were non-linear association between daytime napping and cognitive impairment in all participants group and longer nighttime sleep duration subgroup (PNon-linear < 0.05, PDaytime napping < 0.05). The LRM revealed no napping (OR = 1.62, 95%CI 1.14-2.30) and excessive napping (1.64 95%CI 1.09-2.48) were related to cognitive impairment in longer nighttime sleep duration subgroup.

CONCLUSIONS

Daytime napping had nonlinear association with cognitive impairment in Chinese elderly population. No napping and excessive daytime napping (>90 minutes) were related to cognitive impairment in participants with 7 and more hours nighttime sleep duration.

Indoor Solid Fuel Use and Non-Neoplastic Digestive System Diseases: A Population-Based Cohort Study Among Chinese Middle-Aged and Older Population

Objectives: We tended to explore the association of indoor air pollution (IAP) and non-neoplastic digestive system diseases (NNDSD) among the Chinese middle-aged and older population. Methods: From 2011 to 2018, we included 7884 NNDSD-free adults from the China Health and Retirement Longitudinal Study (CHARLS). Physician-diagnosed NNDSD was obtained by self-reported information at baseline and updated across follow-up surveys. We investigated the associations between baseline exposure of solid fuel use for cooking and/or heating and NNDSD diagnosed during follow-up through Cox proportional hazard models. Furthermore, we examined the relationship between cooking fuel switching and NNDSD diagnosed during follow-up. Results: Solid fuel use for cooking and/or heating was positively associated with NNDSD after adjusting for potential confounders. The risk of NNDSD among subjects who always use solid fuel for cooking (adjusted hazard ratio [aHR]: 1.42; 95% confidence interval [CI]: 1.09, 1.84) was higher than those with always clean fuels. Moreover, we found a lower NNDSD risk among participants who switched from solid to clean cooking fuel (aHR: 0.65; 95% CI: 0.49, 0.87) than those with always solid fuels. Conclusion: Our present study shows that indoor solid fuel use is a dependent risk factor for NNDSD. Moreover, switching to clean fuel may contribute to the prevention of digestive system illnesses.

Indoor air pollution from solid fuels use, inflammation, depression and cognitive function in middle-aged and older Chinese adults

BACKGROUND

Few studies have focused on the influence of indoor air pollution on depression and cognitive impairment; besides, the underlying mechanism is not well-established.

OBJECTIVE

This study aimed to fill the above gaps by exploring the underlying influence mechanism of solid fuel use, the major cause of indoor air pollution, with the risk of depression and cognitive impairment.

METHODS

This data came from China Health and Retirement Longitudinal Study (CHARLS) 2015 dataset. Self-reported household cooking fuels were collected and categorized as clean fuels and solid fuels. High-sensitivity C-reactive protein (CRP) and white blood cells (WBC) were used to measure inflammation. Depression and cognitive function were assessed by using standardized questionnaires.

RESULTS

Respondents had an average Center for Epidemiologic Studies Depression Scale (CESD-10) scores of 7.68 (SD = 6.14) and cognitive function scores of 15.97 (SD = 4.84). In the whole sample, 36.4 % of respondents used solid fuels use, but this proportion was much greater among those living in rural areas (78.38 %). Compared with clean fuel users, solid fuel users had more depression and worse cognitive function. After adjusting for confounders, indoor air pollution was significantly associated with depression and cognitive function respectively (β = -0.444, p < 0.001; β = 0.656, p < 0.001). Indoor air pollution was significantly related to the WBC (β = 0.170, p < 0.01), but not for the CRP. The WBC mediated the association between indoor air pollution and depression (β = 0.026, p < 0.01).

CONCLUSION

In conclusion, solid fuel use was significantly associated with a higher risk of depression and cognitive impairment. Furthermore, we found that solid fuel use influences depression partly via the inflammatory profile.

Association between household air pollution from solid fuel use and risk of chronic diseases and their multimorbidity among Chinese adults

BACKGROUND

Given the increasing burden of chronic conditions, multimorbidity is now a priority for public health systems worldwide. However, the relationship between household air pollution (HAP) exposure with multimorbidity remains unclear.

METHODS

We used three waves data (2011, 2013, and 2015) including 19,295 participants aged ≥ 45 years from the China Health and Retirement Longitudinal Study, to investigate the association between HAP exposure from solid fuel use for heating and cooking with the risk of chronic multimorbidity. Multimorbidity was defined as the coexistence of two or more of 15 chronic diseases (hypertension, diabetes, dyslipidemia, heart disease, stroke, cardiovascular disease, chronic lung disease, asthma, kidney disease, liver disease, digestive disease, cancer, psychiatric disease, memory-related disease, and arthritis). Multiple logistic regression investigated the association between solid fuel use for heating and cooking, separately or simultaneously, with the risk of multimorbidity. Poisson regression with quasi-likelihood estimation explored whether solid fuel exposure could increase the number of morbidities. Stratified analyses and sensitivity analyses examined the effect modification and robustness of the association.

RESULTS

Of the 19,295 participants (mean age: 58.9 years), 40.9 % have multimorbidity. Compared with participants who used clean fuels for heating and cooking, the risk was higher in mixed fuel (adjusted odds ratio, aOR = 1.26, 95 %CI:1.16-1.36) and solid fuel users (aOR = 1.81, 1.67-1.98) separately. HAP from solid fuel use was positively associated with an increased number of morbidities (adjusted β = 0.329, 0.290 to 0.368), after controlling for confounders. Those living in a one-story building, with poor household cleanliness have a higher risk of multimorbidity. No significant modifications of those associations by the socio-demographic and behaviour characteristics was observed.

CONCLUSIONS

HAP from solid fuel use is associated with a high risk of chronic multimorbidity in Chinese adults. Our findings provide important implications for reducing chronic disease burden by restricting solid fuel use.

Associations between household solid fuel use and activities of daily living trajectories: A nationwide longitudinal study of middle and older adults in China

BACKGROUND

More studies focus on reporting the effects of ambient air pollution on physical activity while ignoring the hazards of indoor air pollution caused by household solid fuel use. Moreover, the impact of individual cognitive and depressive status on the health effects of air pollution is often overlooked.

OBJECTIVE

We examined the association between household solid fuel and activities of daily living (ADL) trajectories, and further examined this association in homogeneous subgroups of cognitive or depressive trajectories.

METHODS

Participants were from the China Health and Retirement Longitudinal Study, which conducted four waves of surveys from 2011 to 2018. We collected information on participants' household fuel use, then the ADL, cognitive and depressive performances were assessed in each wave. The latent growth mixture model (LGMM) was used to identify the optimal trajectory class for ADL, cognition, and depression. Then, the multinomial logistic regression was used to assess the association between solid fuel use and ADL trajectories in total population, as well as subgroups with different cognitive or depression trajectories. Furthermore, we examined the association between switching household fuel types and ADL trajectories across the four-wave survey.

RESULTS

The study sample included 7052 participants. We identified three ADL trajectory classes in total population: "Low-stable", "Moderate-anterior rise", and "Moderate-posterior rise". The multinomial logistic regression results showed that solid fuel use was associated with elevated odds for the adverse ADL trajectories, and this association was still shown in homogeneous subgroups of cognitive or depressive trajectories, while some effects were less significant. In addition, the risk of adverse ADL trajectories generally increases with the times of solid fuel use across the four-wave survey.

CONCLUSIONS

For middle and older adults in China, household solid fuel use was not conducive to physical activity development, which inspires that a further transformation to cleaner fuels is an important intervention.

Sarcopenia and mild cognitive impairment among elderly adults: The first longitudinal evidence from CHARLS

BACKGROUND

The association between sarcopenia and mild cognitive impairment (MCI) among elderly adults in China remains unclear. The present study aimed to examine the association based on a nationally representative large-scale survey.

METHODS

The study used two waves of data from China Health and Retirement Longitudinal Study (CHARLS) in 2015 and 2018. All subjects met the inclusion criteria were classified based on Asia Working Group for Sarcopenia 2019 criteria. Aging-associated cognitive decline is used to define MCI, and cognitive function is measured based on four dimensions: orientation, computation, memory, and drawing. OLS and logistic regression model were conducted to analyse the cross-sectional association between sarcopenia and different cognitive functions. Logistic regression model was conducted to analyse the longitudinal association between sarcopenia and MCI.

RESULTS

Totally, 5715 participants aged over 60 years (43.8% women; mean age 67.3 ± 6.0 years) were enrolled in a cross-sectional association study in 2015, and further 2982 elderly adults were followed up in 2018. During the period, sarcopenia and possible sarcopenia increased from 8.5% to 29.6%. Scores of cognitive and four dimensions (orientation, computation, memory, and drawing) exhibited a decreasing trend from non-sarcopenia to sarcopenia (P < 0.001). In the fully adjusted OLS regression model, scores of four dimensions were lower in possible sarcopenia and sarcopenia groups when compared with the non-sarcopenia group (P < 0.05) respectively. The incidence of MCI was 10.1%, 16.5%, and 24.2% for non-sarcopenia, possible sarcopenia, and sarcopenia groups from 2015 to 2018, with a significantly statistical difference (P < 0.001). Logistic regression model revealed an odds ratio of 1.43 [95% confidence interval (CI): 1.06-1.91, P = 0.017] for the possible sarcopenia group and 1.72 (95% CI: 1.04-2.85, P = 0.035) for sarcopenia group when compared with the non-sarcopenia group.

CONCLUSIONS

Sarcopenia is associated with worse cognitive impairment, which provided new evidence for a strong association that warrants further research into mechanistic insights.