Association between Indoor Air Pollution and Cognitive Impairment among Adults in Rural Puducherry, South India

Ambient ammonium exposure is associated with physical dysfunction in older adults in China

The health effects associated with particulate matter (PM) are extensively reported; nevertheless, limited research has explored the exact contributions of its chemical constituents to physical dysfunctional aging. This study assesses the relationships between prolonged exposure to significant ambient air pollutants, especially ammonium (NH4+), and physical dysfunction in a nationally representative cohort of older Chinese adults. We investigated data from 14,641 participants aged 45 years or older in the 2015 wave of the China Health and Retirement Longitudinal Study (CHARLS), which was integrated with high-resolution air pollution data from the ChinaHighAirPollutants (CHAP) dataset. Physical dysfunction was evaluated by self-reported challenges in executing routine activities. After controlling for a wide range of confounders, associations among eight air contaminants (averaged from 2013 to 2015) and dysfunction risk were investigated using logistic regression models. Multicollinearity among covariates in the fully adjusted models was assessed using the generalized variance inflation factor (GVIF), with a threshold value of 5 adopted as the criterion to indicate potential collinearity. Sensitivity analyses-including exclusion of high-exposure participants, standardized z-score modeling, stratified subgroup evaluations, and multipollutant adjustments-were performed to assess the robustness of associations. Dose-response relationships were modeled using both quartile-based logistic regression and restricted cubic spline (RCS) models, revealing consistent and complementary trends. To estimate independent effects and address potential collinearity, we further constructed a multipollutant model adjusting for seven co-pollutants. In all and fully adjusted models, ambient ammonium (NH4+) was the only air pollutant that demonstrated a significant and independent association with physical dysfunction (OR: 1.03; 95% CI: 1.01-1.05; p < 0.05); no significant associations were found for the other pollutants. This association remained robust across multiple sensitivity analyses, including exclusion of extreme exposure (OR: 1.13; 95% CI: 1.08-1.17; p < 0.001), z-score standardization (OR: 2.17; 95% CI: 1.57-2.98; p < 0.001), and 5 stratified subgroup models. A significant dose-response relationship was identified both in quartile-based trend tests (p for trend < 0.001) and restricted cubic spline analysis (p for non-linearity < 0.001). Taken together, the monotonic trend from quartile analysis and the non-linear pattern from spline modeling suggest that even moderate exposure to NH4⁺ may contribute to physical dysfunction. Furthermore, multicollinearity diagnostics based on generalized variance inflation factors (GVIFs) indicated no evidence of problematic collinearity among covariates in the fully adjusted models (all GVIF < 5). Besides, the association remained significant and became stronger in a multipollutant model, highlighting the independent effect of NH4+ beyond co-pollutant confounding (OR: 1.49; 95% CI: 1.26-1.76; p < 0.001). Our findings indicate that NH4+, a significant secondary component of PM predominantly sourced from agricultural ammonia emissions, may uniquely contribute to the deterioration of physical function. It may be important to evaluate particle chemical makeup for analyzing health concerns, as there is no association for total PM mass. Long-lasting exposure to ambient NH4+ has been independently associated with increased odds of physical dysfunction across older adults in China. These findings underscore the necessity for specific environmental strategies focused on ammonia reduction to alleviate age-related functional deterioration and foster healthy aging.

Modification effect of healthy lifestyle among solid fuels and mild cognitive impairment in middle-aged and older adults: A prospective cohort study

To explore the association between solid fuels and mild cognitive impairment (MCI) and the role of the healthy lifestyle score (HLS) in the association between solid fuels and MCI. Data were obtained from CHARLS from 2011 to 2020. A logistic regression model which assessed the impact of solid fuel use on MCI was applied. A full HLS was constructed to evaluate the interaction and joint effects of HLS with solid fuels. 11054 people were enclosed in this study and the proportion of the population using solid fuels is as high as 74.05 % for heating fuels and 56.53 % for cooking fuels. Results showed that solid fuel use was positively associated with the risk of MCI during cooking and heating, with 95 % confidence intervals (95 % CI) of 1.11 (1.00, 1.23) for cooking and 1.14 (1.00, 1.31) for heating. Further, a healthy BMI was beneficial in reducing the harmful effects of solid fuels. Solid fuel use was significantly associated with MCI among middle-aged and older Chinese adults. Our results also suggested that higher HLS is beneficial in reducing the risk of MCI from solid fuels. In this study, we are prompted to use cleaner fuels and ventilation equipment along with the need to develop effective HLS measures for interventions.

Next generation brain health: transforming global research and public health to promote prevention of dementia and reduce its risk in young adult populations

Efforts to prevent dementia can benefit from precision interventions delivered to the right population at the right time; that is, when the potential to reduce risk is the highest. Young adults (aged 18-39 years) are a neglected population in dementia research and policy making despite being highly exposed to several known modifiable risk factors. The risk and protective factors that have the biggest effect on dementia outcomes in young adulthood, and how these associations differ across regions and groups, still remain unclear. To address these uncertainties, the Next Generation Brain Health team convened a multidisciplinary expert group representing 15 nations across six continents. We identified several high-priority modifiable factors in young adulthood and devised five key recommendations for promoting brain health, ranging from individual to policy levels. Increasing research and policy focus on brain health across the life course, inclusive of younger populations, is the next crucial step in the efforts to prevent dementia at the global level.

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.

A study about the impact of indoor air pollution on cognitive function among middle-aged and older adult people in India

BACKGROUND

In the 21st century, people still use solid fuel for cooking at home, resulting in poor indoor air quality. Prolonged exposure to such conditions may negatively affect one's cognitive function. So, the present study examines the possible association between IAP and the cognitive function of individuals aged 45 years or above in India.

METHODS

The study utilizes secondary data, procured from the longitudinal ageing study in India (2017-18). Treatment effects through regression-adjusted models were applied to represent the association between IAP and cognitive health and the results are represented by beta coefficient (β). Three separate models with a 95% confidence interval adjusting with the other factors like housing environment, individual and behavioural were framed.

RESULTS

The study revealed that households without a separate kitchen (β = -0.64; 95%CI: -0.90 to -0.39) and electricity (β = -0.97; 95%CI: -1.34 to -0.61) significantly affect cognitive strength. Cognitive decline is likely more pronounced among older adults (β = -1.19; 95%CI: -1.42 to -0.96) than the middle-aged population. Moreover, the cognitive ability of rural residents (β = -1.11; 95%CI: -1.49 to -0.73) and women (β = -2.05; 95%CI: -2.29 to -1.81) is negatively associated with IAP exposure. Older adults with no reading habits (β = -6.28; 95%CI: -6.72; to -5.85) and physical inactivity (β = -0.96; 95%CI: -1.22 to -0.70) had a sign of notable decline in cognitive ability.

CONCLUSIONS

Findings revealed that cognitive function is negatively associated with IAP, demanding a deep intervention plan to minimize the detrimental effect.

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.

Exploring the links between indoor air pollutants and health outcomes in South Asian countries: a systematic review

Indoor air pollution (IAP) has adverse effects on the health of people, globally. The objective of this systematic review was to present the range of health problems studied in association with indoor air pollutants in South Asian countries. We searched five databases, including PubMed, Web of Science, Scopus, Google Scholar, and CAB Direct for articles published between the years 2000 and 2020. We retrieved 5,810 articles, out of which we included 90 articles in our review. Among South Asian countries, only five countries have published results related to relationship between indoor air pollutants and adverse health conditions. All studies have shown adversity of indoor air pollutants on human's health. We found indoor solid fuel burning as a key source of indoor air pollution in the included studies, while women and children were most affected by their exposure to solid fuel burning. More than half of the studies accounted particulate matter responsible for indoor air pollution bearing negative health effects. In the included studies, eyes and lungs were the most commonly affected body organs, exhibiting common symptoms like cough, breathing difficulty and wheezing. This might have developed into common conditions like respiratory tract infection, chronic obstructive pulmonary diseases and eye cataract. In addition to promote research in South Asian countries, future research should focus on novel digital ways of capturing effects of indoor air pollutants among vulnerable segments of the population. As a result of this new knowledge, public health agencies should develop and test interventions to reduce people's exposure levels and prevent them to develop adverse health outcomes.

Mitigating the impact of air pollution on dementia and brain health: Setting the policy agenda

BACKGROUND

Emerging research suggests exposure to high levels of air pollution at critical points in the life-course is detrimental to brain health, including cognitive decline and dementia. Social determinants play a significant role, including socio-economic deprivation, environmental factors and heightened health and social inequalities. Policies have been proposed more generally, but their benefits for brain health have yet to be fully explored.

OBJECTIVE AND METHODS

Over the course of two years, we worked as a consortium of 20+ academics in a participatory and consensus method to develop the first policy agenda for mitigating air pollution's impact on brain health and dementia, including an umbrella review and engaging 11 stakeholder organisations.

RESULTS

We identified three policy domains and 14 priority areas. Research and Funding included: (1) embracing a complexities of place approach that (2) highlights vulnerable populations; (3) details the impact of ambient PM_2.5 on brain health, including current and historical high-resolution exposure models; (4) emphasises the importance of indoor air pollution; (5) catalogues the multiple pathways to disease for brain health and dementia, including those most at risk; (6) embraces a life course perspective; and (7) radically rethinks funding. Education and Awareness included: (8) making this unrecognised public health issue known; (9) developing educational products; (10) attaching air pollution and brain health to existing strategies and campaigns; and (11) providing publicly available monitoring, assessment and screening tools. Policy Evaluation included: (12) conducting complex systems evaluation; (13) engaging in co-production; and (14) evaluating air quality policies for their brain health benefits.

CONCLUSION

Given the pressing issues of brain health, dementia and air pollution, setting a policy agenda is crucial. Policy needs to be matched by scientific evidence and appropriate guidelines, including bespoke strategies to optimise impact and mitigate unintended consequences. The agenda provided here is the first step toward such a plan.

Household air pollution and cognitive health among Indian older adults: Evidence from LASI

BACKGROUND

Previous shreds of evidence have suggested that ambient air pollution is negatively associated with cognitive health among older adults, but whether indoor air pollutants such as cooking fuel, tobacco smoke, and incense burning exposure affect the cognitive score is unknown, especially in limited-resource areas.

METHOD

The study has utilized the recently released data from the Longitudinal Ageing Study of India (LASI), Wave 1, conducted from 2017 to 2018. A total of 63,883 (≥45 years) older adults were considered for the analysis. Descriptive statistics, bivariate analysis and ordinary least squares regression were employed in the study.

RESULTS

The estimated mean cognitive score was 25.4 and the percentage of solid fuel users was 45.6 in India. The cognitive score gap between the two groups was more remarkable in Tamil Nadu (clean fuels: 29.7; solid fuels: 23.9). A significant cognitive score gap was observed for all indoor air pollutants, i.e., cooking fuel (clean: 29.7 and solid fuels: 23.9), exposure to tobacco smoke (not exposed: 25.7 and exposed: 24.4), and exposure to daily incense burning (not exposed: 25.9 and exposed: 24.8). The unadjusted model found that a one-unit increase of using charcoal/lignite/coal reduces the cognitive score by 5 (95% CI: -5.36, -4.61). A similar effect of exposure to tobacco smoke (β = -0.79, 95% CI: -0.89, -0.68) and incense burning (β = -0.28, 95% CI: -0.30, -0.26) was explored in the study. After adjusting socioeconomic and demographic characteristics, indoor air pollution was found to be a significant determinant of cognitive health.

CONCLUSIONS

The study has identified exposure to indoor air pollution as a risk factor for cognitive impairment among older adults. Therefore, we suggest an urgent need of promoting existing schemes like the Pradhan Mantri Ujjwala Yojana and creating awareness about the adverse effects of indoor air pollutants for a better future.

Household air pollution from solid fuel use as a dose-dependent risk factor for cognitive impairment in northern China

The relationship between exposure to household air pollution (HAP) from solid fuel use and cognition remains poorly understood. Among 401 older adults in peri-urban northern China enrolled in the INTERMAP-China Prospective Study, we estimated the associations between exposure to HAP and z-standardized domain-specific and overall cognitive scores from the Montreal Cognitive Assessment. Interquartile range increases in exposures to fine particulate matter (53.2-µg/m3) and black carbon (0.9-µg/m3) were linearly associated with lower overall cognition [- 0.13 (95% confidence interval: - 0.22, - 0.04) and - 0.10 (- 0.19, - 0.01), respectively]. Using solid fuel indoors and greater intensity of its use were also associated with lower overall cognition (range of point estimates: - 0.13 to - 0.03), though confidence intervals included zero. Among individual cognitive domains, attention had the largest associations with most exposure measures. Our findings indicate that exposure to HAP may be a dose-dependent risk factor for cognitive impairment. As exposure to HAP remains pervasive in China and worldwide, reducing exposure through the promotion of less-polluting stoves and fuels may be a population-wide intervention strategy to lessen the burden of cognitive impairment.

Association between indoor air pollution and cognitive function among nationally representative sample of middle-aged and older adults in India-A multilevel modelling approach

We have used a nationally representative sample of middle-aged and older adults in India to study the association between indoor air pollution and cognitive function. Longitudinal aging study in India (LASI) Wave-I data was utilized for this study. A two-level mixed-effects linear regression model was used to study the association between indoor air pollution and cognitive function and interpreted as adjusted beta coefficient (ꞵ) with 95% confidence interval (CI). In total, 56,179 participants aged ≥45 years were included in the analysis. The proportion of participants living in households with indoor air pollution were 30.6% (95%CI: 30.0%-31.3%). After adjusting for all the potential confounders (age, gender, education, region, religion, separate kitchen, socioeconomic status, marital status, residence, smoking, alcohol consumption, body mass index, self-rated health, and sleep problems), participants living in households with indoor air pollution had significant decline in the cognitive function when compared to those living in households without indoor air pollution (ꞵ = -0.57; 95%CI: -0.69 to -0.45). Since the LASI survey is being conducted as a biennial panel survey, assessing the impact of indoor air pollution on cognitive decline using the follow-up data can provide further insights into the pathogenesis of condition.

Household use of polluting cooking fuels and late-life cognitive function: A harmonized analysis of India, Mexico, and China

INTRODUCTION

Exposure to high levels of air pollution is associated with poor health, including worse cognitive function. Whereas many studies of cognition have assessed outdoor air pollution, we evaluate how exposure to air pollution from combustion of polluting household fuels relates with cognitive function using harmonized data from India, Mexico, and China.

MATERIALS & METHODS

We analyze adults age 50+ in three nationally representative studies of aging with common data collection methods: the 2017-2019 Longitudinal Aging Study in India (n = 50,532), 2015 Mexican Health and Aging Study (n = 12,883), and 2013 China Health and Retirement Longitudinal Study (n = 12,913). Use of polluting fuels was assessed by self-report of wood, coal, kerosene, crop residue, or dung for cooking. Cognitive function was measured by performance across several cognitive domains and summarized into a total cognition score. We used linear regression, by country, to test how polluting cooking fuel use relates with cognition adjusting for key demographic and socioeconomic factors.

RESULTS

Approximately 47%, 12%, and 48% of respondents in India, Mexico, and China, respectively, relied primarily on polluting cooking fuel, which was more common in rural areas. Using polluting cooking fuels was consistently associated with poorer cognitive function in all countries, independent of demographic and socioeconomic characteristics. Adjusted differences in cognitive function between individuals using polluting and clean cooking fuel were equivalent to differences observed between individuals who were 3 years of age apart in Mexico and China and 6 years of age apart in India. Across countries, associations between polluting cooking fuel use and poorer cognition were larger for women.

CONCLUSIONS

Results suggest that household air pollution from the use of polluting cooking fuel may play an important role in shaping cognitive outcomes of older adults in countries where reliance on polluting fuels for domestic energy needs still prevails. As these countries continue to age, public health efforts should seek to reduce reliance on these fuels.

Cooking with biomass fuels increased the risk for cognitive impairment and cognitive decline among the oldest-old Chinese adults (2011-2018): A prospective cohort study

BACKGROUNDS

While the pernicious effects of outdoor air pollution on cognitive ability have been previously examined, evidence regarding household air pollution is scarce.

METHODS

Using data from the Chinese Longitudinal Healthy Longevity Survey, we explored the relationship between cooking with biomass fuel and cognitive impairment and cognitive decline using a Cox proportional hazards model. We further assessed the correlation of biomass fuels and cognitive score using a generalized estimating equation. Cognitive ability was measured based on the Chinese version of the Mini-Mental State Examination (MMSE) and cognitive impairment was defined as MMSE < 24 points and cognitive decline was defined as a reduction of MMSE ≥ 3 points. On follow-up, we investigated the effect of switch-cooking combustibles on cognitive ability.

RESULTS

The mean (SD) age of 4161 participants was 81.7 (10.0) years old. The reported cooking with biomass fuels was correlated with an elevated risk of cognitive impairment (hazard ratio (HR): 1.19, 95% confidence interval (CI): 1.04, 1.37) and cognitive decline (HR: 1.18, 95% CI: 1.04, 1.33). Besides, cooking with biomass fuels was related to a decrease in cognitive score (β: -0.43, 95% CI: -0.73, -0.14). In comparison to persistent biomass fuel users, participants who reported changing their primary cooking fuels from biomass to clean fuels exhibited a reduced risk of cognitive impairment (HR: 0.68, 95% CI: 0.57, 0.82) and cognitive decline (HR: 0.66, 95% CI: 0.56, 0.76) and a higher cognitive score (β: 0.72, 95% CI: 0.17, 1.26). Cooking without ventilated cookstoves was associated with a higher risk of cognitive impairment (HR: 1.31, 95% CI: 1.10, 1.58) and cognitive decline (HR: 1.18, 95% CI: 1.02, 1.38), regardless of types of cooking fuels. Interaction and stratified analyses showed relatively poor cognitive ability in participants who engaged in irregular exercise or were not living with family members.

CONCLUSIONS

Cooking with biomass fuels was correlated with a higher risk of cognitive impairment and cognitive decline. Among the oldest-old population, this risk may, however, be lower for those changing their primary cooking fuels from biomass to clean fuels.

Solid cooking fuel use and cognitive decline among older Mexican adults

Studies of air pollution and cognition often rely on measures from outdoor environments. Many individuals in low- and middle-income countries are exposed to indoor air pollution from combustion of solid cooking fuels. Little is known about how solid cooking fuel use affects cognitive decline over time. This study uses data from the 2012, 2015, and 2018 Mexican Health and Aging Study (n = 14 245, age 50+) to assess how use of wood or coal for cooking fuel affects cognition of older adults relative to use of gas. It uses latent change score modeling to determine how using solid cooking fuel affected performance in Verbal Learning, Verbal Recall, Visual Scanning, and Verbal Fluency. Solid cooking fuel was used by 17% of the full sample but was more common in rural areas. Solid fuel users also had lower socioeconomic status. Compared to those using gas, solid fuel users had lower baseline scores and faster decline in Verbal Learning (β = -0.18, p < 0.05), Visual Scanning (β = -1.00, p < 0.001), and Verbal Fluency (β = -0.33, p < 0.001). Indoor air pollution from solid cooking fuels may represent a modifiable risk factor for cognitive decline. Policy should focus on facilitating access to clean cooking fuels.

Investigating Cooking Activity Patterns and Perceptions of Air Quality Interventions among Women in Urban Rwanda

Household air pollution (HAP) from biomass cooking with traditional stoves is a major cause of morbidity and mortality in low-and-middle-income countries (LMICs) worldwide. Air quality interventions such as improved cookstoves (ICS) may mitigate HAP-related impacts; however, poor understanding of contextual socio-cultural factors such as local cooking practices have limited their widespread adoption. Policymakers and stakeholders require an understanding of local cooking practices to inform effective HAP interventions which meet end-user needs. A semi-structured questionnaire was administered to 36 women residing in biomass-cooking fuel households in Kigali, Rwanda to identify cooking activity patterns, awareness of HAP-related health risks and ICS intervention preferences. Overall, 94% of respondents exclusively used charcoal cooking fuel and 53% cooked one meal each day (range = 1-3 meals). Women were significantly more likely to cook outdoors compared to indoors (64% vs. 36%; p < 0.05). Over half of respondents (53%) were unaware of HAP-related health risks and 64% had no prior awareness of ICS. Participants expressed preferences for stove mobility (89%) and facility for multiple pans (53%) within an ICS intervention. Our findings highlight the need for HAP interventions to be flexible to suit a range of cooking patterns and preferred features for end-users in this context.

Sex difference in the association between solid fuel use and cognitive function in rural China

BACKGROUND

Whether indoor air pollution from solid fuel use is associated with cognitive function remains unclear.

OBJECTIVE

This study aims to examine the association of solid fuel use with the risk of cognitive impairment in males and females.

METHODS

The data was from the China Health and Retirement Longitudinal Study (CHARLS). Self-reported heating and cooking fuel were categorized as clean fuel (solar, liquefied gas, natural gas, or electricity) and solid fuel (coal, biomass charcoal, wood, or straw). Cognitive function, including orientation and attention, episodic memory, and visuospatial abilities, was assessed using standardized questionnaires.

RESULTS

A total of 7824 individuals were included in our study (aged 57.0 ± 9.3, 46.2% female), with 47.0% and 76.0% used solid fuel for cooking and heating, respectively. There was an interaction between sex and solid fuel use for cooking (P=0.008) for the progress of cognitive impairment. Solid fuel use for cooking was associated with a larger decrease in cognitive function score in females (β=-0.832; 95% CI: -1.043, -0.622; P < 0.001) than in males (β=-0.487; 95% CI: -0.671, -0.302; P < 0.001). The sex difference remained with further adjustment of covariates (β=-0.321; 95% CI: -0.503, -0.138; P=0.001 for males; β=-0.534; 95% CI: -0.745, -0.324; P < 0.001 for females). For heating, the interaction between sex and solid fuel was not statistically significant (P=0.156). After controlling for the covariates, solid fuel use for heating was inversely associated with a 0.321 unit of decrease of cognitive function score (β=-0.321; 95% CI: -0.652, 0.009; P=0.057) in males, and a 0.598 unit of decrease of cognitive function (β=-0.598; 95% CI: -0.978, -0.218; P=0.002) in females.

CONCLUSION

In conclusion, solid fuel use for cooking and heating was significantly associated with a higher risk of cognitive impairment. Furthermore, for the first time, we found that the effect of solid fuel use on cognitive function in females was greater than in males.

Association between biomass fuel use and the risk of cognitive impairment among older populations in China: a population-based cohort study

BACKGROUND

Cohort studies on the impact of biomass fuel use for cooking on cognitive impairment among older population are still lacking in China and elsewhere. The aim of this study was to examine whether biomass fuel use for cooking is associated with cognitive impairment in Chinese adults aged 65 years or older.

METHODS

The prospective population-based cohort study of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) included participants aged 65 years or older in 2014 who were followed-up until 2018 in 23 provinces in China. The Mini-Mental State Examination (MMSE) was used to assess cognitive function, and cognitive impairment was defined as total MMSE scores less than 18. The association between biomass fuel use and cognitive impairment was evaluated using the Cox proportional hazards model.

RESULTS

Of the 4145 participants included at baseline, participants who reported that they used biomass fuel for cooking (40.43%; IR: 3.11 versus 2.77 per 100 person-years; aHR: 1.27, 95% CI: 1.02-1.58) had a higher risk of cognitive impairment compared with participants who used clean fuels (53.75%). A stratified analyses showed greater effect estimates of cognitive impairment in the older people that lived in the rural areas (aHR: 1.444, 95% CI: 1.08-3.90) and never smoked (aHR: 1.33, 95% CI: 1.04-1.71).

CONCLUSIONS

These findings demonstrated that biomass fuel used for cooking was associated with cognitive impairment, as defined by MMSE, in a population-based study of elderly in China. To prevent cognitive impairment, the structure of cooking fuels requires improvements.

The effects of indoor air pollution from solid fuel use on cognitive function among middle-aged and older population in China

OBJECTIVES

Growing evidence has linked outdoor air pollution exposure with higher risk of cognitive impairments. However, the role of indoor air pollution in cognitive decline is not well elaborated. By using nationally representative longitudinal data, this study aimed to explore the effects of indoor air pollution from solid fuel use on cognitive function among middle-aged and older individuals in China.

METHODS

Data were obtained from 2011 to 2015 waves of CHARLS (China Health and Retirement Longitudinal Study). Scores from the Telephone Interview of Cognitive Status and figure drawing/word recall tests were used to measure cognitive function in 39,482 individuals. Exposure to indoor air pollution was measured as use of solid fuel for cooking. Solid fuel was defined as coal, biomass charcoal, wood, and straw; clean fuel was defined as liquefied gas, natural gas, and electricity. Linear mixed effect models were applied to examine the effect of indoor air pollution from solid fuel use on cognitive function.

RESULTS

Participants had an average global cognitive function of 9.67 (SD = 4.13). Solid fuel users made up 49.71% of participants, but this proportion was much greater among those living in rural areas (64.22%). Compared with clean fuel users, solid fuel users had worse cognitive function. On average, solid fuel users had a 0.81 (95%CI: -0.89, -0.73) lower global cognition score, 0.63 (95%CI: -0.69, -0.57) lower mental health score, and 0.16 (95%CI: -0.22, -0.14) lower episodic memory score. These effects were stronger among participants who are female, aged 65 years old and above, have education level of primary school and below, or have cardiovascular diseases.

CONCLUSIONS

These results provide evidence for the role of indoor air pollution in neurobehavioral disorders in China. Promotion of practices like expanded use of clean fuel and improved stoves in households may be crucial to significantly reduce indoor air pollution and protect mental health.

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

BACKGROUND

To date, few studies have focused on the influence of indoor air pollution on cognitive impairment. Thus, we aimed to explore the association of household fuel use, the major cause of household air pollution, with cognitive functioning among a sample of middle-aged and older Chinese individuals.

METHODS

A total of 10,372 and 8,397 participants from the China Health and Retirement Longitudinal Study (CHARLS) were enrolled in the cross-sectional and follow-up analyses, respectively. Cognitive functioning was evaluated via a structured questionnaire in three dimensions: orientation and attention, episodic memory, and visuo-construction. The associations between household solid fuel use (for cooking and heating) and cognitive functioning were elucidated by generalized linear models. Furthermore, we explored the combined effect of solid fuel use in cooking and heating and examined the effects of switching cooking fuel types on a 4-year change in cognitive functioning.

RESULTS

In the cross-sectional study, solid fuel use for cooking or heating, separately or simultaneously, was positively associated with cognitive impairment, after adjusting for potential confounders. Similarly, in the follow-up study, solid cooking fuel use was associated with a greater decline in cognitive score overall (β = -0.24, 95% confidence interval [CI]: -0.45, -0.04), mostly in the episodic memory (β = -0.19, 95% CI: -0.34, -0.03) and visuo-construction (β = -0.03, 95% CI: -0.05, -0.01) dimensions; solid heating fuel use was associated only with a greater decrease in the orientation and attention dimension (β = -0.13, 95% CI: -0.25, -0.01). A combined effect of household fuel use was also observed (P < 0.05). Moreover, subjects who switched from solid to cleaner cooking fuel displayed a significantly lower degree of cognitive decline for all dimensions than did persistent solid fuel users over a 4-year period (P < 0.05).

CONCLUSION

Our findings show that household solid fuel use is a risk factor for the development of cognitive impairment. Improving the structure of cooking fuel may therefore have great public health value for the prevention of cognitive impairment.

Indoor particulate air pollution from open fires and the cognitive function of older people

Exposure to indoor air pollution is known to affect respiratory and cardiovascular health, but little is known about its effects on cognitive function. We measured the concentrations and magnetite content of airborne particulate matter (PM) in the indoor environment arising from burning peat, wood or coal in residential open fires. Highest indoor PM_2.5 concentrations (60 μg/m³ i.e. 2.4 times the WHO-recommended 24-h mean) occurred when peat was burned, followed by burning of coal (30 μg/m³) and wood (17 μg/m³). Conversely, highest concentrations of coarser PM (PM_10-2.5) were associated with coal burning (20 μg/m³), with lower concentrations emitted during burning of wood (10 μg/m³) and peat (8 μg/m³). The magnetic content of the emitted PM, greatest (for both PM size fractions) when coal was burned, is similar to that of roadside airborne PM. Exposure to PM, and to strongly magnetic airborne PM, can be greater for individuals spending ~5 h/day indoors with a coal-burning open fire for 6 months/year compared to those commuting via heavily-trafficked roads for 1 h/day for 12 months/year. Given these high indoor PM and magnetite concentrations, and the reported associations between (outdoor) PM and impaired neurological health, we used individual-level data from The Irish Longitudinal Study on Ageing (TILDA) to examine the association between the usage of open fires and the cognitive function of older people. Using a sample of nearly seven thousand older people, we estimated multi-variate models of the association between cognitive function and open fire usage, in order to account for relevant confounders such as socio-economic status. We found a negative association between open fire usage and cognitive function as measured by widely-used cognitive tests such as word recall and verbal fluency tests. The negative association was largest and statistically strongest among women, a finding explained by the greater exposure of women to open fires in the home because they spent more time at home than men. Our findings were also robust to stratifying the sample between old and young, rich and poor, and urban and rural.

The effect of PM2.5 exposure and risk perception on the mental stress of Nanjing citizens in China

The multidimensional characteristics and temporal dynamics of environmental risks have stimulated a social-scientific approach towards air pollution issues in recent decades. It's now widely acknowledged that air pollution has an ineligible influence on the psychological wellbeing of citizens beyond its well-established physical impact. We explored how fine particulate matter (PM_2.5), an essential air pollutant associated with morbidity and mortality, interacted with aspects of risk perception to influence citizen's mental stress level. Questionnaire data from 508 Nanjing citizens in China were collected across four seasons within an 18-month period. We found no evidence that mental stress was directly influenced by real-time PM_2.5 exposure. However, path analysis revealed that mental stress was subjected to the indirect influence of physical symptoms (β = 0.076, p = 0.11), by increasing perceived effect on health and increasing attribution to indoor pollution sources (β = 0.038, p = 0.005). Indoor attribution of PM_2.5 pollution was associated with perceived familiarity with risk (β = -0.095, p = 0.033), whereas outdoor attribution was associated with perceived control of risk (β = 0.091, p = 0.041). Public risk acceptable rate (PRAR) decreased as PM_2.5 concentration increased. In females, but not males, greater trust for government was associated with the increased acceptance of PM_2.5 (Year₂₀₁₇: β = -0.19, p = 0.003; Year₂₀₂₂: β = -0.21, p < 0.001). Using psychological statistical methods, our study implied that air pollution has a substantial association with psychological wellbeing in various ways, which might provide some references for public healthcare and risk communication.