Long-term Exposure to Multiple Ambient Air Pollutants and Association With Incident Depression and Anxiety

Prenatal exposure to ambient air pollution and persistent postpartum depression

BACKGROUND

Ambient air pollution during pregnancy has been linked with postpartum depression up to 12 months, but few studies have investigated its impact on persistent depression beyond 12 months postpartum. This study aimed to evaluate prenatal ambient air pollution exposure and the risk of persistent depression over 3 years after childbirth and to identify windows of susceptibility.

METHODS

This study included 361 predominantly low-income Hispanic/Latina participants with full-term pregnancies in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort. We estimated daily residential PM2.5, PM10, NO2, and O3 concentrations throughout 37 gestational weeks using inverse-distance squared spatial interpolation from monitoring data and calculated weekly averaged levels. Depression was assessed by the 20-item Center for Epidemiologic Studies-Depression (CES-D) scale at 12, 24, and 36 months postpartum, with persistent postpartum depression defined as a CES-D score ≥16 at any of these timepoints. We performed robust Poisson log-linear distributed lag models (DLM) via generalized estimating equations (GEE) to estimate the adjusted risk ratio (RR).

RESULTS

Depression was observed in 17.8 %, 17.5 %, and 13.4 % of participants at 12, 24, and 36 months, respectively. We found one IQR increase (3.9 ppb) in prenatal exposure to NO2 during the identified sensitive window of gestational weeks 13-29 was associated with a cumulative risk ratio of 3.86 (95 % CI: 3.24, 4.59) for persistent depression 1-3 years postpartum. We also found one IQR increase (7.4 μg/m3) in prenatal exposure to PM10 during gestation weeks 12-28 was associated a cumulative risk ratio of 3.88 (95 % CI: 3.04, 4.96) for persistent depression. No clear sensitive windows were identified for PM2.5 or O3.

CONCLUSIONS

Mid-pregnancy PM10 and NO2 exposures were associated with nearly 4-fold increased risks of persistent depression after pregnancy, which has critical implications for prevention of perinatal mental health outcomes.

Trace elements in PM2.5 from 2016 to 2021 in Shenzhen, China: Concentrations, temporal and spatial distribution, and related human inhalation exposure risk

The prevalence of trace elements from industrial and traffic activities poses potential health risks through inhalation exposure. Prior studies have focused on trace elements in water, food, and dust, and less attention has been paid to their occurrence in fine particulate matter (PM2.5). In this study, 1424 air samples were collected from three districts (Nanshan, Longgang, and Yantian) in Shenzhen from 2016 to 2021, and we analyzed the concentrations, temporal trends, and spatial distributions of PM2.5 and associated trace elements. Both PM2.5 and trace elements exhibited decreasing trends and similar seasonal variations, with high levels in cold seasons and low levels in warm seasons. In terms of spatial distributions, the concentrations of PM2.5 and trace elements in Nanshan and Longgang were significantly higher than those in Yantian, likely due to the industrial structure and traffic activities. It is worth noting that PM2.5 was identified as a potential mediator of the effect of meteorological parameters on trace element levels. Besides, the values of estimated daily intake (EDI) and uptake (EDU) suggested that infants and young children experienced an elevated risk of exposure to trace elements. While the annual average excess hazard indexes (R) were below the safety threshold (10-6), carcinogenic trace elements like arsenic (As) and chromium (Cr) posed a greater potential threat to human health compared to non-carcinogenic trace elements.

Sufficient sleep and physical activity can relieve the effects of long-term exposure to particulate matter on depressive symptoms among 0.31 million children and adolescents from 103 counties in China

BACKGROUND

Although long-term exposures to air pollutants have been linked to mental disorders, existing studies remain limited and inconsistent. We investigated the relationship between exposure to particulate matter (PM) and depressive symptoms, as well as the potential role of sleep duration and physical activity.

METHOD

Using the surveillance data (2019 to 2022) of common diseases and risk factors among 312,390 students aged 10-25 years, logistic regression, generalized liner model (GLM) and restricted cubic spline (RCS) were employed to investigate the relationship between long-term exposure to PM and depressive symptoms.

RESULT

Significant associations were found between PM1 (OR = 1.21, 95 % CI: 1.12-1.32), PM2.5 (OR = 1.24, 95 % CI: 1.19-1.38), and PM10 (OR = 1.87, 95 % CI: 1.69-2.07) and increased risks of depressive symptoms. Sleep duration and physical activity relieved these associations. The odds ratios (ORs) of PM1, PM2.5, and PM10 on depressive symptoms were lower in group with sufficient sleep (1.02 vs. 1.49, 1.20 vs. 1.80, 2.15 vs. 2.23), lower in group with high level MVPA (1.13 vs. 1.48, 1.14 vs. 1.58, 1.85 vs. 2.38), and lower in group with high level outdoor activity (1.19 vs. 1.55, 1.23 vs. 1.63, 1.83 vs. 2.72).

LIMITATIONS

Conclusions about causality remain speculative because of the cross-sectional design.

CONCLUSION

Sufficient sleep duration and outdoor activity may mitigate the decline in mental health among adults in developing countries caused by long-term exposure to PM. This contribution enhanced our understanding of the mechanisms linking air pollution to mental health.

Time-varying ambient air pollution exposure is associated with gut microbiome variation in the first 2 years of life

The infant gut microbiome matures greatly in the first year of life. Ambient air pollution (AAP) exposure is associated with the infant gut microbiome. However, whether time-varying AAP influences infant gut microbiome variation is rarely investigated. This study aimed to investigate the effects of PM2.5, PM10, and O3 on infant gut microbiome variation longitudinally. Demographic information, stool samples, and AAP exposure concentrations were collected at 6, 12, 24 months from infants. Gut microbiome was processed and analyzed using 16S rRNA V3-V4 gene regions. AAP exposure concentrations were calculated using the China High Air Pollutants (CHAP) database. Multiple pollutant models were used to assess the mixed effects of PM2.5, PM10, and O3 on infant gut microbiome variation. Infants' gut microbiomes at 6, 12, 24 months old had significant differences in alpha diversity, beta diversity, and community composition. PM2.5 and O3 respectively explained 6.3% and 5.3% of the differences in community composition for 24-month-old infants. Single pollutant exposure and multiple pollutant exposure in different periods were both associated with alpha diversity indices and specific gut microbial phyla and genera. AAP was more associated with infant gut microbial alpha diversity indices, phyla variations, and genera variations at 12-24 months than 6-12 months. Multiple pollutant exposure in 0-2 lag months showed negative correlations with 12-24 months variation in Escherichia-Shigella (β = -0.854, 95%CI: 1.398 to -0.310) and Enterococcus (β = -0.979, 95%CI: 1.429 to -0.530). This study highlighted that time-varying PM2.5, PM10, and O3 synergistically influenced the variation of alpha diversity and abundance of gut microbial taxa in infants. Further research is needed to explore the effects and mechanisms of other environmental exposures on infant gut microbiome variation.

Expose to volatile organic compounds is associated with increased risk of depression: A cross-sectional study

With increasing prevalence rate of depression by years, more attention has been paid to the influence of environmental pollutants on depression, but relationship between exposure to volatile organic compounds (VOCs) and depression is rarely studied. Therefore, this cross-sectional study use the National Center for Health Statistics (NHANES) database (2013-2016 years) to explore association between exposure to multiple VOCs and depression in general population. Multiple linear and logistic regression models were used to analyze the association between urinary VOC metabolism (mVOCs) and depression. To further analyze effect of multiple mVOCs mixed exposure, Bayesian kernel machine regression (BKMR) models were performed. A total of 3240 participants and 16 mVOCs were included in the analysis. Results showed that 10 mVOCs exposure were positively correlated with depression by multiple linear and logistic regression models, especially CYMA and MHBMA3, which also showed significant positive association with depression in BKMR model. Mixed exposure of multiple mVOCs was significantly positively correlated with depression. Gender differences were existed in effects of some VOCs concentrations on depression. AAMA, CYMA and MA had significant positive correlations with depression by women, and DHBMA had significant positive correlations with depression by men. Hence, this study showed that exposing to VOCs might have negative impacts on depression, and impact of CYMA and MHBMA3 on depression may be more evident, which provide new ideas for prevention and control of depression. But further research and exploration are needed to clarify the mechanism and influence factors of this relationship, to demonstrate the reliability of these relationship.

Fine particulate matter components associated with exacerbated depressive symptoms among middle-aged and older adults in China

Growing awareness acknowledges ambient fine particulate matter (PM2.5) as an environmental risk factor for mental disorders, especially among older people. However, there remains limited evidence regarding which specific chemical components of PM2.5 may be more detrimental. This nationwide prospective cohort study included 22,126 middle-aged and older adult participants of the China Health and Retirement Longitudinal Study (CHARLS, 2011-2016), to explore the individual and joint associations between long-term exposure to various PM2.5 components (sulfate, nitrate, ammonium, organic matter, and black carbon) and depressive symptoms. The depressive symptoms were assessed using the 10-item Center for Epidemiological Studies-Depression Scale (CES-D-10). Using the novel quantile-based g-computation for multi-pollutant mixture analysis, we found that exposure to the mixture of major PM2.5 components was significantly associated with aggravating depressive symptoms, with the exposure-response curve exhibiting consistent linear or supra-linear shape without a lower threshold. The estimated weight index indicated that, among major PM2.5 components, only nitrate, sulfate, and black carbon significantly contributed to the exacerbation of depressive symptoms. Given the expanding aging population, stricter regulation on the emissions of particularly toxic PM2.5 components may mitigate the escalating disease burden of depression.

Residential air pollution, greenspace, and adverse mental health outcomes in the U.S. Gulf Long-term Follow-up Study

Air pollution and greenness are environmental determinants of mental health, though existing evidence typically considers each exposure in isolation. We evaluated relationships between co-occurring air pollution and greenspace levels and depression and anxiety. We estimated cross-sectional associations among 9015 Gulf Long-term Follow-up Study participants living in the southeastern U.S. who completed the Patient Health Questionnaire-9 (depression: score ≥ 10) and Generalized Anxiety Disorder Questionnaire-7 (anxiety: score ≥ 10). Participant residential addresses were linked to annual average concentrations of particulate matter (1 km PM2.5) and nitrogen dioxide (1 km NO2), as well as satellite-based greenness (2 km Enhanced Vegetation Index (EVI)). We used adjusted log-binomial regression to estimate prevalence ratios (PR) and 95 % confidence intervals (CI) for associations between exposures (quartiles) and depression and anxiety. In mutually adjusted models (simultaneously modeling PM2.5, NO2, and EVI), the highest quartile of PM2.5 was associated with increased prevalence of depression (PR = 1.17, 95 % CI: 1.06-1.29), whereas the highest quartile of greenness was inversely associated with depression (PR = 0.89, 95 % CI: 0.80-0.99). Joint exposure to greenness mitigated the impact of PM2.5 on depression (PRPM only = 1.20, 95 % CI: 1.06-1.36; PRPM+green = 0.98, 95 % CI: 0.83-1.16) and anxiety (PRPM only = 1.10, 95 % CI: 1.00-1.22; PRPM+green = 0.95, 95 % CI: 0.83-1.09) overall and in subgroup analyses. Observed associations were stronger in urbanized areas and among nonwhite participants, and varied by neighborhood deprivation. NO2 exposure was not independently associated with depression or anxiety in this population. Relationships between PM2.5, greenness, and depression were strongest in the presence of characteristics that are highly correlated with lower socioeconomic status, underscoring the need to consider mental health as an environmental justice issue.

A genome-wide gene-environmental interaction study identified novel loci for the relationship between ambient air pollution exposure and depression, anxiety

BACKGROUND

Genetic factors and environmental exposures, including air pollution, contribute to the risk of depression and anxiety. While the association between air pollution and depression and anxiety has been established in the UK Biobank, there has been limited research exploring this relationship from a genetic perspective.

METHODS

Based on individual genotypic and phenotypic data from a cohort of 104,385 participants in the UK Biobank, a polygenic risk score for depression and anxiety was constructed to explore the joint effects of nitric oxide (NO), nitrogen dioxide (NO2), particulate matter (PM) with a diameter of ⩽2.5 μm (PM2.5) and 2.5-10 μm (PMcoarse) with depression and anxiety by linear and logistic regression models. Subsequently, a genome-wide gene-environmental interaction study (GWEIS) was performed using PLINK 2.0 to identify the genes interacting with air pollution for depression and anxiety.

RESULTS

A substantial risk of depression and anxiety development was detected in participants exposed to the high air pollution concomitantly with high genetic risk. GWEIS identified 166, 23, 18, and 164 significant candidate loci interacting with NO, NO2, PM2.5, and PMcoarse for Patient Health Questionnaire-9 (PHQ-9) score, and detected 44, 10, 10, and 114 candidate loci associated with NO, NO2, PM2.5, and PMcoarse for General Anxiety Disorder (GAD-7) score, respectively. And some significant genes overlapped among four air pollutants, like TSN (rs184699498, PNO2 = 3.47 × 10-9; rs139212326, PPM2.5 = 1.51 × 10-8) and HSP90AB7P(rs150987455, PNO2 = 1.63 × 10-11; rs150987455, PPM2.5 = 7.64 × 10-11), which were common genes affecting PHQ-9 score for both NO2 and PM2.5.

CONCLUSION

Our study identified the joint effects of air pollution with genetic susceptibility on the risk of depression and anxiety, and provided several novel candidate genes for the interaction, contributing to an understanding of the genetic architecture of depression and anxiety.

Do social economic status modify the association between air pollution and depressive or anxiety symptoms? A big sample cross-sectional study from the rural areas of Central China

BACKGROUND

Fewer studies have examined the relationship between air pollution and depressive or anxiety symptoms in rural residents. Social economic status (SES), as an important indicator of the current state of socioeconomic development, we know little about how it modifies the relationship between air pollution and symptoms of depression or anxiety.

METHODS

The patient health questionnaire (PHQ-2) and generalized anxiety scale (GAD-2) were used to learn about the prevalence of depressive and anxiety symptoms, the social economic status of the participants was categorized into two levels: lower and higher, and a binary logistic regression model was used to analyze the relationship between air pollution and residents' symptoms of depression or anxiety.

RESULTS

A total of 10,670 adults were enrolled in this study, of which a total of 1292 participants suffered from depressive symptoms and 860 suffered from anxiety symptoms. Short-term exposure to PM2.5 and O3, singly or in combination, may be associated with the onset of depression symptoms, and there was a significant interaction between SES and exposure to PM2.5 or O3. Residents of areas with higher SES may have a lower risk of suffering from anxiety symptoms after O3 exposure compared to participants living in lower SES.

LIMITATIONS

The study was a cross-sectional study, which may have lowered the quality level of the evidence.

CONCLUSIONS

Short-term PM2.5 and O3 exposure may be associated with an increased prevalence risk of depressive symptoms. Higher levels of SES may reduce the adverse effects of air pollution on depressive or anxiety symptoms.

The association between preserved ratio impaired spirometry and adverse outcomes of depression and anxiety: evidence from the UK Biobank

BACKGROUND

Preserved ratio impaired spirometry (PRISm) is a new lung function impairment phenotype and has been recognized as a risk factor for various adverse outcomes. We aimed to examine the associations of this new lung function impairment phenotype with depression and anxiety in longitudinal studies.

METHODS

We included 369 597 participants from the UK Biobank cohort, and divided them into population 1 without depression or anxiety and population 2 with depression or anxiety at baseline. Cox proportional hazard models were performed to evaluate the associations of lung function impairment phenotype with adverse outcomes of depression and anxiety, as well as their subtypes.

RESULTS

At baseline, 38 879 (10.5%) participants were diagnosed with PRISm. In population 1, the adjusted hazard ratios (HRs) for PRISm (v. normal spirometry) were 1.12 (95% CI 1.07-1.18) for incident depression, and 1.11 (95% CI 1.06-1.15) for incident anxiety, respectively. In population 2, PRISm was a risk factor for mortality in participants with depression (HR: 1.46; 95% CI 1.31-1.62) and anxiety (HR: 1.70; 95% CI 1.44-2.02), compared with normal spirometry. The magnitudes of these associations were similar in the phenotypes of lung function impairment and the subtypes of mental disorders. Trajectory analysis showed that the transition from normal spirometry to PRISm was associated with a higher risk of mortality in participants with depression and anxiety.

CONCLUSIONS

PRISm and airflow obstruction have similar risks of depression and anxiety. PRISm recognition may contribute to the prevention of depression and anxiety.

Uncovering the impact and mechanisms of air pollution on eye and ear health in China

Increasing air pollution could undermine human health, but the causal link between air pollution and eye and ear health has not been well-studied. Based on four-week-level records of eye and ear health over 1991-2015 provided by the China Health and Nutrition Survey, we estimate the causal effect of air pollution on eye and ear health. Using two-stage least squares estimation, we find that eye or ear disease possibility rises 1.48% for a 10 μg/m3 increase in four-week average PM2.5 concentration. The impacts can last about 28 weeks and will be insignificant afterward. Females, individuals aged 60 years and over, with high exposure environments, relatively poor economic foundations, and low knowledge levels are more vulnerable to such negative influences. Behavioral channels like more smoking activities and less sleeping activities could partly explain this detrimental effect. Our findings enlighten how to minimize the impact of air pollution and protect public health.

Association between window ventilation frequency and depressive symptoms among older Chinese adults

OBJECTIVES

Indoor air pollution exposure is harmful to people's physical and mental health, especially in the elderly population. Depressive symptoms are the most common mental health issue among elderly individuals. However, evidence linking the frequency of indoor natural ventilation to depressive symptoms in the elderly population is limited.

METHODS

This study included 7887 individuals 65 years and older from 2017 to 2018 the China Longitudinal Healthy Longevity Survey (CLHLS). The frequency of indoor window ventilation was measured as the self-reported times of ventilation of indoor window per week in each season, and the four seasons' scores were added up to calculate the annual ventilation frequency. Depressive symptoms were measured by the 10-item Center for Epidemiologic Studies Short Depression Scale (CESD). Using three models adjusted for demographic, socio-economic, health status, and environmental factors successively, the correlation between indoor window ventilation frequency and depressive symptoms was verified through logistic regression.

RESULTS

Among the 7887 elderly people included in this study, 1952 (24.7 %) had depressive symptoms. In the fully adjusted model, compared with the lower indoor annual ventilation frequency group, high indoor annual ventilation frequency group was significantly associated with a 33 % (OR: 0.67, 95%CI: 0.51-0.88) lower probability of depressive symptoms. Subgroup analysis and sensitivity analysis yielded similar results.

CONCLUSIONS

High frequency of window ventilation is significantly associated with the lower risk of depressive symptoms in Chinese individuals aged 65 and older. This result provides strong evidence for health intervention and policy formulation.

Air pollution exposure, chemical compositions, and risk of expiratory airflow limitation in youth in Northeast China

BACKGROUND

Expiratory airflow limitation (EAL) is closely associated with respiratory health in youth and adulthood. Owing to limited evidence, we aim to estimate the association between air pollutants, both individually and in combination, along with their chemical compositions, and the risk of EAL in youth based on data obtained from Northeast China Biobank.

METHODS

Pulmonary function was evaluated using a medical-grade pulmonary function analyzer, with EAL defined as a forced expiratory flow in 1 s/ forced vital capacity ratio of < 0.8. Land use regression models were used to predict exposure to six air pollutants. Air pollution score (APS) for each participant was constructed as combined exposure. The chemical composition of particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) was determined using a validated machine-learning algorithm. Logistic regression models were employed to estimate effect sizes, and odds ratio (OR) and 95 % confidence intervals (CI) were calculated.

RESULTS

In total, 905 EAL cases were identified among the 4301 participants, with a prevalence of 21.04 %. Each inter-quartile range increase in APS was associated with a 25 % higher risk of EAL (OR = 1.25, 95 % CI: 1.12, 1.39). Among the pollutants analyzed, PM2.5 exposure had the strongest association with the risk of EAL (OR = 1.33, 95 % CI: 1.18, 1.52). Out of the five chemical components, sulfate (SO2-4) (OR = 1.39, 95 % CI: 1.24, 1.57) and ammonium (NH+4) (OR = 1.39, 95 % CI: 1.23, 1.57) exhibited the strongest associations with the risk of EAL.

CONCLUSIONS

Overall, combined effects of air pollution increased the risk of EAL in youth, with SO2-4 and NH+4 emerging as the predominant contributing chemical components in Northeast China.

Long-term effects of fine particulate matter components on depression among middle-aged and elderly adults in China: A nationwide cohort study

BACKGROUND

Fine particulate matter (PM2.5) has been implicated in various health concerns. However, a comprehensive understanding of the specific PM2.5 components affecting depression remains limited.

METHODS

This study conducted a Cox proportional-hazards model to assess the effect of PM2.5 components on the incidence of depression based on the China Health and Retirement Longitudinal Study (CHARLS). Participants with 10-item Center for Epidemiologic Studies Depression Scale (CESD-10) score of 10 or higher were classified as exhibiting depression.

RESULTS

Our findings demonstrated a significant positive correlation between long-term exposure to black carbon (BC), sulfate (SO42-), and organic matter (OM) components of PM2.5 and the prevalence of depression. Per 1 Interquartile Range (IQR) increment in 3-year average concentrations of BC, OM, and SO42- were associated with the hazard ratio (HR) of 1.54 (95 % confidence intervals (CI): 1.44, 1.64), 1.24 (95%CI: 1.16, 1.34) and 1.25 (95%CI: 1.16, 1.35). Notably, females, younger individuals, those with lower educational levels, urban residents, individuals who were single, widowed, or divorced, and those living in multi-story houses exhibited heightened vulnerability to the adverse effects of PM2.5 components on depression.

LIMITATIONS

Firstly, pollutant data is confined to subjects' fixed addresses, overlooking travel and international residence history. Secondly, the analysis only incorporates five fine particulate components, leaving room for further investigation into the remaining fine particulate components in future studies.

CONCLUSIONS

This study provides robust evidence supporting the detrimental impact of PM2.5 components on depression. The identification of specific vulnerable populations contributes to a deeper understanding of the underlying mechanisms involved in the relationship between PM2.5 components and depression.

A Systematic Review of Air Pollution Exposure and Brain Structure and Function during Development

Objectives

Air pollutants are known neurotoxicants. In this updated systematic review, we evaluate new evidence since our 2019 systematic review on the effect of outdoor air pollution exposure on childhood and adolescent brain structure and function as measured by magnetic resonance imaging (MRI).

Methods

Using PubMed and Web of Science, we conducted an updated literature search and systematic review of articles published through March 2024, using key terms for air pollution and functional and/or structural MRI. Two raters independently screened all articles using Covidence and implemented the risk of bias instrument for systematic reviews informing the World Health Organization Global Air Quality Guidelines.

Results

We identified 222 relevant papers, and 14 new studies met our inclusion criteria. Including six studies from our 2019 review, the 20 publications to date include study populations from the United States, Netherlands, Spain, and United Kingdom. Studies investigated exposure periods spanning pregnancy through early adolescence, and estimated air pollutant exposure levels via personal monitoring, geospatial residential estimates, or school courtyard monitors. Brain MRI occurred when children were on average 6-14.7 years old; however, one study assessed newborns. Several MRI modalities were leveraged, including structural morphology, diffusion tensor imaging, restriction spectrum imaging, arterial spin labeling, magnetic resonance spectroscopy, as well as resting-state and task-based functional MRI. Air pollutants were associated with widespread brain differences, although the magnitude and direction of findings are largely inconsistent, making it difficult to draw strong conclusions.

Conclusion

Prenatal and childhood exposure to outdoor air pollution is associated with structural and functional brain variations. Compared to our initial 2019 review, publications doubled-an increase that testifies to the importance of this public health issue. Further research is needed to clarify the effects of developmental timing, along with the downstream implications of outdoor air pollution exposure on children's cognitive and mental health.

Socioeconomic inequalities, genetic susceptibility, and risks of depression and anxiety: A large-observational study

OBJECTIVES

This study aimed to investigate the interplay between genetic susceptibility and socioeconomic disparities on psychiatric disorders.

METHODS

In this study, we utilized data from the UK Biobank to analyze the Generalized Anxiety Disorder (GAD)-7 scale (N = 74,425) and the Patient Health Questionnaire (PHQ)-9 (N = 74,101), along with the Index of Multiple Deprivation (IMD). The polygenic risk score (PRS) was calculated to assess the genetic risk associated with GAD-7/PHQ-9 scores, and the individuals were classified into low, medium, and high genetic risk groups according to tertiles of PRSs related to the GAD-7/PHQ-9. Linear regression models were used to explore the relationships between GAD-7/PHQ-9 scores and IMD scores in patients with different genetic susceptibilities.

RESULTS

Disadvantaged socioeconomic status was associated with the risk of anxiety and depression across all strata of genetic risk, and stronger associations were shown for individuals with greater genetic susceptibility. From low to high genetic risk, the risk of psychiatric disorders increased for the GAD-7 (β = 0.002 to 0.032) and PHQ-9 (β = 0.003 to 0.045) scores. In addition, strong associations of high genetic risk with anxiety (β = 0.875) and depression (β = 1.152) were detected in the IMD quartile 4 group compared with the least deprivation quartile group. Furthermore, income and employment were estimated to contribute strongly to anxiety (βemployment = 7.331, βincome = 4.492) and depression (βemployment = 9.951, βincome = 6.453) in the high genetic risk group.

CONCLUSION

The results suggest that we should pay more attention to psychiatric disorders with high genetic susceptibility and try to improve their socioeconomic status to prevent the development of psychiatric disorders.

Long-term Exposure to Ambient Air Pollution and its Association with Mental Well-Being, Depression and Anxiety: A Nationally Representative Study

INTRODUCTION

Exposure to ambient air pollution may play a role in the onset of common mental disorders like depressive and anxiety disorders. The association of long-term exposure to particles smaller than 10 μm (PM10) with these diseases remains unclear. This study aimed to estimate the association of long-term exposure to PM10 with mental well-being and the frequency of probable diagnosis of common mental disorders.

METHODS

A nationally representative cross-sectional study was done in mainland Portugal. Long-term exposure was estimated through one-year average concentrations of PM10, calculated with data from the Portuguese Environment Agency, attributed individually considering individuals' postal codes of residence. The mental well-being and the probable diagnosis of common mental disorders were ascertained through the five-item Mental Health Inventory scale. Linear and Robust Poisson regression models were computed to estimate change percentages, prevalence ratios (PR), and their 95% confidence intervals (95% CI).

RESULTS

The median (interquartile range) concentration of PM10 was 18.6 (15.3 - 19.3) μg/m3. The mental well-being score was 72 (56 - 84) points, on a scale from 0 to 100. A probable diagnosis of common mental disorders was found in 22.7% (95% CI: 20.0 to 25.6). Long-term exposure to PM10 was associated with a non-statistically significant decrease in the mental well-being score [for each 10 μg/m³ increment in one-year average PM10 concentrations, there was a 2% (95% CI: -8 to 4) decrease], and with a non-statistically significant increase in the common mental health frequency (PR = 1.012, 95% CI: 0.979 to 1.045).

CONCLUSION

We did not find statistically significant associations between long-term exposure to PM10 and mental well-being or the frequency of probable diagnosis of common mental disorders. These results may be explained by the reduced variability in the exposure values, given the geographical distribution and functioning of the network of air quality monitoring stations. This study contributes with evidence for low levels of air pollutants, being one of the first to adjust for individual and aggregate-level variables. Moreover, to the best of our knowledge, this was the first nationally representative, population-based study conducted on the Portuguese population using real-life data. Maintaining a robust and nationwide air quality monitoring network is essential for obtaining quality exposure data.

Associations of ambient air pollution and lifestyle with the risk of NAFLD: a population-based cohort study

BACKGROUND

Both ambient air pollution and lifestyle factors contribute to the incidence of non-alcoholic fatty liver disease (NAFLD), but previous studies usually focused on single-factor associations. We aimed to assess the joint associations of ambient air pollution and lifestyle with the NAFLD risk and investigate whether lifestyle modifies the association of air pollution with NAFLD risk.

METHODS

A total of 417,025 participants from the UK Biobank were included in this study. Annual average concentrations of NO2, NOx, PM2.5, PM10, and PM2.5-10 were estimated. A composite lifestyle score was determined based on physical activity, alcohol intake, smoking status, dietary patterns, sedentary time, and sleep duration. Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs), as well as the population attributable fraction (PAF). Potential additive interactions of air pollution with lifestyle were also examined by the relative excess risk due to the interaction (RERI) and the attributable proportion due to the interaction (AP).

RESULTS

4752 (1.14%) incident NAFLD events were recorded. Long-term exposure to air pollutants and an unhealthy lifestyle were significantly associated with the increased risk of incident NAFLD. Lifestyle was the primary factor of incident NAFLD, with a PAF of 37.18% (95% CI: 29.67%, 44.69%). In addition, a significant additive interaction between air pollution and lifestyle for NAFLD risk was observed (RERI: 0.36, 95% CI: 0.09-0.63).

CONCLUSIONS

Long-term exposure to ambient air pollutants and poor lifestyle were jointly associated with a higher risk of NAFLD.

Fine particulate matter (PM2.5) induces testosterone disruption by triggering ferroptosis through SIRT1/HIF-1α signaling pathway in male mice

Fine particulate matter (PM2.5), a significant component of air pollution particulate matter, is inevitable and closely associated with increasing male reproductive disorder. However, the testicular targets of PM2.5 and its toxicity related molecular mechanisms are still not fully understood. In this study, the conditional knockout (cKO) mice and primary Leydig cells were used to explore the testicular targets of PM2.5 and the related underlying mechanisms. First, apparent the structure impairment of seminiferous tubules, Leydig cells vacuolization, decline of serum testosterone and sperm quality reduction were found in male wild-type (WT) and Sirt1 knockout mice after exposure to PM2.5. Enrichment analyses revealed that differentially expressed genes (DEGs) were enriched in steroid hormone biosynthesis, ferroptosis, and HIF-1 signaling pathway in the mice testes after exposure to PM2.5, which were subsequently verified by the molecular biological analyses. Notably, similar enrichment analyses results were also observed in primary Leydig cells after treatment with PM2.5. In addition, Knockdown of Sirt1 significantly increased PM2.5-induced expression and activation of HIF-1α, which was in parallel to the changes of cellular iron levels, oxidative stress indicators and the ferroptosis markers. In conclusion, this highlights that PM2.5 triggers ferroptosis via SIRT1/HIF-1α signaling pathway to inhibit testosterone synthesis in males. These findings provide a novel research support for the study that PM2.5 causes male reproductive injury.

Estimation of Attributable Risk and Direct Medical and Non-Medical Costs of Major Mental Disorders Associated With Air Pollution Exposures Among Children and Adolescents in the Republic of Korea, 2011-2019

BACKGROUND

Recent studies have reported the burden of attention deficit hyperactivity disorder [ADHD], autism spectrum disorder [ASD], and depressive disorder. Also, there is mounting evidence on the effects of environmental factors, such as ambient air pollution, on these disorders among children and adolescents. However, few studies have evaluated the burden of mental disorders attributable to air pollution exposure in children and adolescents.

METHODS

We estimated the risk ratios of major mental disorders (ADHD, ASD, and depressive disorder) associated with air pollutants among children and adolescents using time-series data (2011-2019) obtained from a nationwide air pollution monitoring network and healthcare utilization claims data in the Republic of Korea. Based on the estimated risk ratios, we determined the population attributable fraction (PAF) and calculated the medical costs of major mental disorders attributable to air pollution.

RESULTS

A total of 33,598 patients were diagnosed with major mental disorders during 9 years. The PAFs for all the major mental disorders were estimated at 6.9% (particulate matter < 10 μm [PM10]), 3.7% (PM2.5), and 2.2% (sulfur dioxide [SO2]). The PAF of PM10 was highest for depressive disorder (9.2%), followed by ASD (8.4%) and ADHD (5.2%). The direct medical costs of all major mental disorders attributable to PM10 and SO2 decreased during the study period.

CONCLUSION

This study assessed the burden of major mental disorders attributable to air pollution exposure in children and adolescents. We found that PM10, PM2.5, and SO2 attributed 7%, 4%, and 2% respectively, to the risk of major mental disorders among children and adolescents.

Associations of long-term exposure to low-level PM2.5 and brain disorders in 260,922 middle-aged and older adults

Long-term exposure to high-level ambient PM2.5 was associated with increased risks of brain disorders, while the associations remain uncertain when the exposure is lower than current air quality standards in numerous countries. This study aimed to assess the effects of PM2.5 exposure on the brain system in the population with annual mean concentrations ≤15 μg/m3. We analyzed data from 260,922 participants without preexisting brain diseases at baseline in the UK Biobank. The geographical distribution of PM2.5 in 2010 was estimated by a land use regression model and linked with individual residential address. We investigated associations of ambient PM2.5 with incident neurological (dementia, Parkinson's diseases [PD], epilepsy, and migraine) and psychiatric (major depressive disorder [MDD] and anxiety disorder) diseases through Cox proportional hazard models. We further estimated the links with brain imaging phenotypes by neuroimaging analysis. Results showed that in the population with PM2.5 concentrations ≤15 μg/m3, each interquartile range (IQR, 1.28 μg/m3) increment in PM2.5 was related to incidence risks of dementia, epilepsy, migraine, MDD, and anxiety disorder with hazard ratios of 1.08 (95% confidence interval [CI]: 1.03, 1.13), 1.12 (1.05, 1.20), 1.07 (1.00, 1.13), 1.06 (1.03, 1.09), and 1.05 (1.02, 1.08), respectively. We did not observe a significant association with PD. The association with dementia was stronger among the population with poor cardiovascular health (measured by Life's Essential 8) than the counterpart (P for interaction = 0.037). Likewise, per IQR increase was associated with specific brain imaging phenotypes, including volumes of total brain (β = -0.036; 95% CI: -0.050, -0.022), white matter (-0.030; -0.046, -0.014), grey matter (-0.030; -0.042, -0.017), respectively. The findings suggest long-term exposure to ambient PM2.5 at low-level still has an adverse impact on the neuro-psychiatric systems. The brain-relevant epidemiological assessment suggests that each country should update the standard for ambient PM2.5 following the World Health Organization Air Quality Guidelines 2021.

Advances in immunology of male reproductive toxicity induced by common environmental pollutants

Humans are exposed to an ever-increasing number of environmental toxicants, some of which have gradually been identified as major risk factors for male reproductive health, even associated with male infertility. Male infertility is usually due to the reproductive system damage, which may be influenced by the exposure to contaminants such as heavy metals, plasticizers, along with genetics and lifestyle. Testicular immune microenvironment (TIM) is important in maintaining normal physiological functions of the testis, whether disturbed TIM after exposure to environmental toxicants could induce reproductive toxicity remains to be explored. Therefore, the current review aims to contribute to the further understanding of exposure and male infertility by characterizing environmental exposures and the effect on TIM. We first summarized the male reproductive toxicity phenotypes induced by common environmental pollutants. Contaminants including heavy metals and plastic additives and fine particulate matter (PM2.5), have been repetitively associated with male infertility, whereas emerging contaminants such as perfluoroalkyl substances and micro(nano)plastics have also been found to disrupt TIM and lead to male reproductive toxicity. We further reviewed the importance of TIM and its homeostasis in maintaining the normal physiological functions of the testis. Most importantly, we discussed the advances in immunology of male reproductive toxicity induced by metals and metalloids, plastic additives, persistent organic pollutants (POPs), micro(nano)plastic and PM2.5 to suggest the importance of reproductive immunotoxicology in the future study of environmental toxicants, but also contribute to the development of effective prevention and treatment strategies for mitigating adverse effects of environmental pollutants on human health.

Associations and attributable burdens in late-life exposure to PM2.5 and its major components and depressive symptoms in middle-aged and older adults: A nationwide cohort study

BACKGROUND

Depression in late life has been associated with reduced quality of life and increased mortality. Whether the chronic fine particular matter (PM2.5) and its components exposure are contributed to the older depression symptoms remains unclear.

METHOD

Middle-aged and older adults (>45 years) were selected from the China Health and Retirement Longitudinal Study during the four waves of interviews. The concentrations of PM2.5 and its major constituents were calculated using near real-time data at a spatial resolution of 10 km during the study period. The depressive symptom was evaluated by the Depression Center for Epidemiologic Studies Depression (CES-D)-10 score. The fix-effect model was applied to evaluate the association between PM2.5 and its major constituents with depressive symptoms. Three three-step methods were used to explore the modification role of sleep duration against the depressive symptoms caused by PM2.5 exposure.

RESULTS

In our study, a total of 52,683 observations of 16,681 middle-aged and older adults were assessed. Each interquartile range (IQR) level of PM2.5 concentration exposure was longitudinally associated with a 2.6 % (95 % confidence interval [CI]: 1.3 %, 4.0 %) increase in the depression CES-D-10 score. Regarding the major components of PM2.5, OM, NO3-, and NH4+ showed the leading toxicity effects, which could increase the depression CES-D-10 score by 2.2 % (95 %CI: 1.0 %, 3.4 %), 2.2 % (0.6 %, 3.9 %), and 2.0 % (95 %CI: 0.6 %, 3.4 %) correspondingly. Besides, males were more susceptible to the worse depressive symptoms caused by PM2.5 and its major components exposure than female subpopulations. Shortened sleep duration might be the mediator of PM2.5-associated depressive symptoms.

CONCLUSION

Our results suggest that long-term exposure to PM2.5 and its major components were associated with an increased risk for depressive symptoms in middle-aged and older adults. Reducing the leading components of PM2.5 may cost-effectively alleviate the disease burden of depression and promote healthy longevity in heavy pollutant countries.

Impact of Respiratory Dust on Health: A Comparison Based on the Toxicity of PM2.5, Silica, and Nanosilica

Respiratory dust of different particle sizes in the environment causes diverse health effects when entering the human body and makes acute or chronic damage through multiple systems and organs. However, the precise toxic effects and potential mechanisms induced by dust of different particle sizes have not been systematically summarized. In this study, we described the sources and characteristics of three different particle sizes of dust: PM2.5 (<2.5 μm), silica (<5 μm), and nanosilica (<100 nm). Based on their respective characteristics, we further explored the main toxicity induced by silica, PM2.5, and nanosilica in vivo and in vitro. Furthermore, we evaluated the health implications of respiratory dust on the human body, and especially proposed potential synergistic effects, considering current studies. In summary, this review summarized the health hazards and toxic mechanisms associated with respiratory dust of different particle sizes. It could provide new insights for investigating the synergistic effects of co-exposure to respiratory dust of different particle sizes in mixed environments.

Adherence to the EAT-Lancet diet and incident depression and anxiety

High-quality diets have been increasingly acknowledged as a promising candidate to counter the growing prevalence of mental health disorders. This study aims to investigate the prospective associations of adhering to the EAT-Lancet reference diet with incident depression, anxiety and their co-occurrence in 180,446 UK Biobank participants. Degrees of adherence to the EAT-Lancet diet were translated into three different diet scores. Over 11.62 years of follow-up, participants in the highest adherence group of the Knuppel EAT-Lancet index showed lower risks of depression (hazard ratio: 0.806, 95% CI: 0.730-0.890), anxiety (0.818, 0.751-0.892) and their co-occurrence (0.756, 0.624-0.914), compared to the lowest adherence group. The corresponding hazard ratios (95% CIs) were 0.711 (0.627-0.806), 0.765 (0.687-0.852) and 0.659 (0.516-0.841) for the Stubbendorff EAT-Lancet index, and 0.844 (0.768-0.928), 0.825 (0.759-0.896) and 0.818 (0.682-0.981) for the Kesse-Guyot EAT-Lancet diet index. Our findings suggest that higher adherence to the EAT-Lancet diet is associated with lower risks of incident depression, anxiety and their co-occurrence.

Association between green space and multiple ambient air pollutants with depressive and anxiety symptoms among Chinese adolescents: The role of physical activity

OBJECTIVE

To explore the association between green space, multiple ambient air pollutants and depressive/anxiety symptoms and the mediating role of physical activity (PA) in Chinese adolescents.

METHOD

A school-based health survey was conducted in eight provinces in China in 2021. 22,868 students aged 14.64 (±1.77) years completed standard questionnaires to record details of depressive, anxiety symptoms and PA. We calculated the average normalized difference vegetation index (NDVI) in circular buffers of 200 m, 500 m and 1000 m and estimated the concentrations of PM10, PM2.5, CO, NO2, O3, SO2 around the adolescents' school addresses.

RESULTS

The exposure-response curves showed that the lower the NDVI value, the higher the risk of depressive and anxiety symptoms. CO, PM2.5 and SO2 and air pollution score were associated with increased risk of depressive and anxiety symptoms. NDVI in all circular buffers decreased the risk of depressive and anxiety symptoms at low levels of PA, but the associations were not significant at high levels of PA. In the subgroup analysis, PM10, PM2.5, CO, NO2, SO2, AQI and air pollution score increased the risk of depressive and anxiety symptoms at low PA levels, but the associations were not significant at high levels of PA. Mediation analysis indicated that the mediating effect of PA on the association between NDVI, NDVI-200 m NDVI-500 m, CO, PM10, PM2.5, SO2, AQI and depressive/anxiety symptoms was statistically significant（p < 0.05）.

CONCLUSION

Middle-high level PA could reduce the strength of association between air pollution and depressive and anxiety symptoms. Meanwhile, the association between green space/air pollution and depressive/anxiety symptoms was partly mediated by PA.

Effects of Pollution Burden on Neural Function During Implicit Emotion Regulation and Longitudinal Changes in Depressive Symptoms in Adolescents

Background

Exposure to environmental pollutants early in life has been associated with increased prevalence and severity of depression in adolescents; however, the neurobiological mechanisms underlying this association are not well understood. In the current longitudinal study, we investigated whether pollution burden in early adolescence (9-13 years) was associated with altered brain activation and connectivity during implicit emotion regulation and changes in depressive symptoms across adolescence.

Methods

One hundred forty-five participants (n = 87 female; 9-13 years) provided residential addresses, from which we determined their relative pollution burden at the census tract level, and performed an implicit affective regulation task in the scanner. Participants also completed questionnaires assessing depressive symptoms at 3 time points, each approximately 2 years apart, from which we calculated within-person slopes of depressive symptoms. We conducted whole-brain activation and connectivity analyses to examine whether pollution burden was associated with alterations in brain function during implicit emotion regulation of positively and negatively valenced stimuli and how these effects were related to slopes of depressive symptoms across adolescence.

Results

Greater pollution burden was associated with greater bilateral medial prefrontal cortex activation and stronger bilateral medial prefrontal cortex connectivity with regions within the default mode network (e.g., temporoparietal junction, posterior cingulate cortex, precuneus) during implicit regulation of negative emotions, which was associated with greater increases in depressive symptoms across adolescence in those exposed to higher pollution burden.

Conclusions

Adolescents living in communities characterized by greater pollution burden showed altered default mode network functioning during implicit regulation of negative emotions that was associated with increases in depressive symptoms across adolescence.

Sex-Specific Association Between Childhood Adversity and Accelerated Biological Aging

Is childhood adversity associated with biological aging, and if so, does sex modify the association, and do lifestyle and mental health mediate the association? A lifespan analysis is conducted using data on 142 872 participants from the UK Biobank to address these questions. Childhood adversity is assessed through the online mental health questionnaire (2016), including physical neglect, physical abuse, emotional neglect, emotional abuse, sexual abuse, and a cumulative score. Biological aging is indicated by telomere length (TL) measured from leukocyte DNA using qPCR, and the shorter TL indicates accelerated biological aging; a lifestyle score is constructed using body mass index, physical activity, drinking, smoking, and diet; mental disorder is assessed using depression, anxiety, and insomnia at the baseline survey. The results reveal a sex-specific association such that childhood adversity is associated with shorter TL in women after adjusting for covariates including polygenic risk score for TL, but not in men. Unhealthy lifestyle and mental disorder partially mediate the association in women. The proportions of indirect effects are largest for sexual and physical abuse. These findings highlight the importance of behavioral and psychological interventions in promoting healthy aging among women who experienced childhood adversity, particularly sexual and physical abuse.

Effects of short- and long-term exposures to multiple air pollutants on depression among the labor force: A nationwide longitudinal study in China

BACKGROUND

Depression prevalence has surged within the labor force population in recent years. While links between air pollutants and depression were explored, there was a notable scarcity of research focusing on the workforce.

METHODS

This nationwide longitudinal study analyzed 27,457 workers aged 15-64. We estimated monthly mean concentrations of fine particulate matter (PM2.5), its primary components, and Ozone (O3) at participants' residences using spatiotemporal models. To assess the relationship between short- (1 to 3 months) and long-term (1 to 2 years) exposure to various air pollutants and depressive levels and occurrences, we employed linear mixed-effects models and mixed-effects logistic regression. We considered potential occupational moderators, such as labor contracts, overtime compensation, and total annual income.

RESULTS

We found significant increases in depression risks within the workforce linked to both short- and long-term air pollution exposure. A 10 μg/m3 rise in 2-year average PM2.5, black carbon (BC), and O3 concentrations correlated with increments in depressive scores of 0.009, 0.173, and 0.010, and a higher likelihood of depression prevalence by 0.5 %, 12.6 %, and 0.7 %. The impacts of air pollutants and depression were more prominent in people without labor contracts, overtime compensation, and lower total incomes.

CONCLUSION

Exposures to air pollutants could increase the risk of depression in the labor force population. The mitigating effects of higher income, benefits, and job security against depression underscore the need for focused mental health interventions.

Visual environment in schools and student depressive symptoms: Insights from a prospective study across multiple cities in eastern China

OBJECTIVE

To investigate the effects of the school visual environment on depressive symptoms in children and adolescents based on cohort study in eastern China. The school visual environment-related indicators included in this study comprise personal factors (visual impairment) and school-related factors (classroom lighting, school green spaces and school air quality).

METHOD

The follow-up cohort comprises 15,348 students from 283 primary and secondary schools in eastern China. This represents the one-year outcomes of a school-based myopia-mental health cohort study. Data collection includes basic demographics (age, gender, region, etc.), physical examination indicators, behavioral indicators, and school visual environment-related indicators.

RESULT

After a one-year follow-up, we found that compared to the more severe vision impairment group (≤4.0), healthy vision group (≥5.0) had a positive effect against the occurrence of depressive symptoms during consecutive follow-ups, with an RR value of 0.61 (95% CI: 0.57-0.66). Higher values of blackboard illumination appear to be associated with greater positive effects, with an RR (Q75%∼Q100% range) value of 0.87(95% CI: 0.81-0.93). School green spaces seem to exhibit relatively good positive effects when in the Q25%∼Q75% range. The combination of physical activity (Weekly high-intensity exercise) with school air quality(PM2.5≤50%)showed a better positive effect, with an RR value of 0.51(95%CI:0.48-0.55).

CONCLUSION

When addressing students' depressive symptoms, it is crucial to improve the visual environment both at the school level and in students' personal level. Paying appropriate attention to modifiable behaviors, like regular participation in high-intensity exercise sessions, can help alleviate students' depressive symptoms.

Exposure to volatile organic compounds and mortality in US adults: A population-based prospective cohort study

Volatile organic compounds (VOCs) are ubiquitous in both indoor and outdoor environments. Evidence on the associations of individual and joint VOC exposure with all-cause and cause-specific mortality is limited. Measurements of 15 urinary VOC metabolites were available to estimate exposure to 12 VOCs in the National Health and Nutritional Examination Survey (NHANES) 2005-2006 and 2011-2018. The environment risk score (ERS) was calculated using LASSO regression to reflect joint exposure to VOCs. Follow-up data on death were obtained from the NHANES Public-Use Linked Mortality File through December 31, 2019. Cox proportional hazard models and restricted cubic spline models were applied to evaluate the associations of individual and joint VOC exposures with all-cause and cause-specific mortality. Population attributable fractions were calculated to assess the death burden attributable to VOC exposure. During a median follow-up of 6.17 years, 734 (8.34 %) deaths occurred among 8799 adults. Urinary metabolites of acrolein, acrylonitrile, 1,3-butadiene, and ethylbenzene/styrene were significantly associated with all-cause, cardiovascular disease (CVD), respiratory disease (RD), and cancer mortality in a linear dose-response manner. Linear and robust dose-response relationships were also observed between ERS and all-cause and cause-specific mortality. Each 1-unit increase in ERS was associated with a 33.6 %, 39.1 %, 109.8 %, and 67.8 % increase for all-cause, CVD, RD, and cancer mortality risk, respectively. Moreover, joint exposure to VOCs contributed to 17.95 % of all-cause deaths, 13.49 % of CVD deaths, 35.65 % of RD deaths, and 33.85 % of cancer deaths. Individual and joint exposure to VOCs may enhance the risk of all-cause and cause-specific mortality. Reducing exposure to VOCs may alleviate the all-cause and cause-specific death burden.

Joint effects of traffic-related air pollution and hypertensive disorders of pregnancy on maternal postpartum depressive and anxiety symptoms

BACKGROUND

Ambient air pollution has been linked to postpartum depression. However, few studies have investigated the effects of traffic-related NOx on postpartum depression and whether any pregnancy-related factors might increase susceptibility.

OBJECTIVES

To evaluate the association between traffic-related NOx and postpartum depressive and anxiety symptoms, and effect modification by pregnancy-related hypertension.

METHODS

This study included 453 predominantly low-income Hispanic/Latina women in the MADRES cohort. Daily traffic-related NOx concentrations by road class were estimated using the California LINE-source dispersion model (CALINE4) at participants' residential locations and averaged across pregnancy. Postpartum depressive and anxiety symptoms were evaluated by a validated questionnaire (Postpartum Distress Measure, PDM) at 1, 3, 6 and 12 months postpartum. Multivariate linear regressions were performed to estimate the associations at each timepoint. Interaction terms were added to the linear models to assess effect modification by hypertensive disorders of pregnancy (HDPs). Repeated measurement analyses were conducted by using mixed effect models.

RESULTS

We found prenatal traffic-related NOx was associated with increased PDM scores. Specifically, mothers exposed to an IQR (0.22 ppb) increase in NOx from major roads had 3.78% (95% CI: 0.53-7.14%) and 5.27% (95% CI: 0.33-10.45%) significantly higher 3-month and 12-month PDM scores, respectively. Similarly, in repeated measurement analyses, higher NOx from major roads was associated with 3.06% (95% CI: 0.43-5.76%) significantly higher PDM scores across the first year postpartum. Effect modification by HDPs was observed: higher freeway/highway and total NOx among mothers with HDPs were associated with significantly higher PDM scores at 12 months postpartum compared to those without HDPs.

IMPACT

This study shows that prenatal traffic-related air pollution was associated with postpartum depressive and anxiety symptoms. The study also found novel evidence of greater susceptibility among women with HDPs, which advances the understanding of the relationships between air pollution, maternal cardiometabolic health during pregnancy and postpartum mental health. Our study has potential implications for clinical intervention to mitigate the effects of traffic-related pollution on postpartum mental health disorders. The findings can also offer valuable insights into urban planning strategies concerning the implementation of emission control measures and the creation of green spaces.

Environmental pollution and extreme weather conditions: insights into the effect on mental health

Environmental pollution exposures, including air, soil, water, light, and noise pollution, are critical issues that may implicate adverse mental health outcomes. Extreme weather conditions, such as hurricanes, floods, wildfires, and droughts, may also cause long-term severe concerns. However, the knowledge about possible psychiatric disorders associated with these exposures is currently not well disseminated. In this review, we aim to summarize the current knowledge on the impact of environmental pollution and extreme weather conditions on mental health, focusing on anxiety spectrum disorders, autism spectrum disorders, schizophrenia, and depression. In air pollution studies, increased concentrations of PM2.5, NO2, and SO2 were the most strongly associated with the exacerbation of anxiety, schizophrenia, and depression symptoms. We provide an overview of the suggested underlying pathomechanisms involved. We highlight that the pathogenesis of environmental pollution-related diseases is multifactorial, including increased oxidative stress, systematic inflammation, disruption of the blood-brain barrier, and epigenetic dysregulation. Light pollution and noise pollution were correlated with an increased risk of neurodegenerative disorders, particularly Alzheimer's disease. Moreover, the impact of soil and water pollution is discussed. Such compounds as crude oil, heavy metals, natural gas, agro-chemicals (pesticides, herbicides, and fertilizers), polycyclic or polynuclear aromatic hydrocarbons (PAH), solvents, lead (Pb), and asbestos were associated with detrimental impact on mental health. Extreme weather conditions were linked to depression and anxiety spectrum disorders, namely PTSD. Several policy recommendations and awareness campaigns should be implemented, advocating for the advancement of high-quality urbanization, the mitigation of environmental pollution, and, consequently, the enhancement of residents' mental health.

Air pollution exposure, accelerated biological aging, and increased thyroid dysfunction risk: Evidence from a nationwide prospective study

BACKGROUND

Long-term air pollution exposure is a major health concern, yet its associations with thyroid dysfunction (hyperthyroidism and hypothyroidism) and biological aging remain unclear. We aimed to determine the association of long-term air pollution exposure with thyroid dysfunction and to investigate the potential roles of biological aging.

METHODS

A prospective cohort study was conducted on 432,340 participants with available data on air pollutants including particulate matter (PM2.5, PM10, and PM2.5-10), nitrogen dioxide (NO2), and nitric oxide (NO) from the UK Biobank. An air pollution score was calculated using principal component analysis to reflect joint exposure to these pollutants. Biological aging was assessed using the Klemera-Doubal method biological age and the phenotypic age algorithms. The associations of individual and joint air pollutants with thyroid dysfunction were estimated using the Cox proportional hazards regression model. The roles of biological aging were explored using interaction and mediation analyses.

RESULTS

During a median follow-up of 12.41 years, 1,721 (0.40 %) and 9,296 (2.15 %) participants developed hyperthyroidism and hypothyroidism, respectively. All air pollutants were observed to be significantly associated with an increased risk of incident hypothyroidism, while PM2.5, PM10, and NO2 were observed to be significantly associated with an increased risk of incident hyperthyroidism. The hazard ratios (HRs) for hyperthyroidism and hypothyroidism were 1.15 (95 % confidence interval: 1.00-1.32) and 1.15 (1.08-1.22) for individuals in the highest quartile compared with those in the lowest quartile of air pollution score, respectively. Additionally, we noticed that individuals with higher pollutant levels and biologically older generally had a higher risk of incident thyroid dysfunction. Moreover, accelerated biological aging partially mediated 1.9 %-9.4 % of air pollution-associated thyroid dysfunction.

CONCLUSIONS

Despite the possible underestimation of incident thyroid dysfunction, long-term air pollution exposure may increase the risk of incident thyroid dysfunction, particularly in biologically older participants, with biological aging potentially involved in the mechanisms.

The brain structure, inflammatory, and genetic mechanisms mediate the association between physical frailty and depression

Cross-sectional studies have demonstrated strong associations between physical frailty and depression. However, the evidence from prospective studies is limited. Here, we analyze data of 352,277 participants from UK Biobank with 12.25-year follow-up. Compared with non-frail individuals, pre-frail and frail individuals have increased risk for incident depression independent of many putative confounds. Altogether, pre-frail and frail individuals account for 20.58% and 13.16% of depression cases by population attributable fraction analyses. Higher risks are observed in males and individuals younger than 65 years than their counterparts. Mendelian randomization analyses support a potential causal effect of frailty on depression. Associations are also observed between inflammatory markers, brain volumes, and incident depression. Moreover, these regional brain volumes and three inflammatory markers-C-reactive protein, neutrophils, and leukocytes-significantly mediate associations between frailty and depression. Given the scarcity of curative treatment for depression and the high disease burden, identifying potential modifiable risk factors of depression, such as frailty, is needed.

PM2.5 exposure contributes to anxiety and depression-like behaviors via phenyl-containing compounds interfering with dopamine receptor

As a global problem, fine particulate matter (PM2.5) really needs local fixes. Considering the increasing epidemiological relevance to anxiety and depression but inconsistent toxicological results, the most important question is to clarify whether and how PM2.5 causally contributes to these mental disorders and which components are the most dangerous for crucial mitigation in a particular place. In the present study, we chronically subjected male mice to a real-world PM2.5 exposure system throughout the winter heating period in a coal combustion area and revealed that PM2.5 caused anxiety and depression-like behaviors in adults such as restricted activity, diminished exploratory interest, enhanced repetitive stereotypy, and elevated acquired immobility, through behavioral tests including open field, elevated plus maze, marble-burying, and forced swimming tests. Importantly, we found that dopamine signaling was perturbed using mRNA transcriptional profile and bioinformatics analysis, with Drd1 as a potential target. Subsequently, we developed the Drd1 expression-directed multifraction isolating and nontarget identifying framework and identified a total of 209 compounds in PM2.5 organic extracts capable of reducing Drd1 expression. Furthermore, by applying hierarchical characteristic fragment analysis and molecular docking and dynamics simulation, we clarified that phenyl-containing compounds competitively bound to DRD1 and interfered with dopamine signaling, thereby contributing to mental disorders. Taken together, this work provides experimental evidence for researchers and clinicians to identify hazardous factors in PM2.5 and prevent adverse health outcomes and for local governments and municipalities to control source emissions for diminishing specific disease burdens.

Traffic-related pollution and symptoms of depression and anxiety among Chinese adults: A population-based study

BACKGROUND

Limited understanding exists regarding the associations of traffic-related pollution with depression and anxiety symptoms in individuals residing within low- and middle-income countries.

METHODS

Data for this study were extracted from the Psychology and Behavior Investigation of Chinese Residents (PBICR) survey, implemented between June 20 and August 31, 2023. We determined residential proximity to major roadways through self-reports and evaluated depression symptoms using the Patient Health Questionnaire-9 (PHQ-9), along with anxiety symptoms assessed through the Generalized Anxiety Disorder-7 (GAD-7). We examined the associations between residential proximity to major roadways and depression and anxiety symptoms using logistic regressions and generalized linear models, while controlling for potential confounding variables.

RESULTS

This study comprised a total of 22,723 participants. The adjusted odds ratios (OR) for depression symptoms were 1.34 (95 % confidence interval (CI) 1.20, 1.51), 1.29 (95 % CI 1.17, 1.43), 1.34 (95 % CI 1.20, 1.49), and 1.32 (95 % CI 1.17, 1.49) among individuals residing within <50 m, 50-100 m, 101-200 m, and 201-300 m, respectively, in comparison to those residing >300 m from a major roadway. Individuals residing <50 m, 50-100 m, 101-200 m, and 201-300 m from a major roadway exhibited adjusted OR for anxiety symptoms of 1.49 (95 % CI 1.30, 1.69), 1.21 (95 % CI 1.07, 1.37), 1.38 (95 % CI 1.21, 1.56), and 1.38 (95 % CI 1.20, 1.59), respectively, in contrast to those residing >300 m.

CONCLUSIONS

This study provides valuable insights into the associations between environmental factors and mental health. The findings underscore the importance of integrating environmental considerations into comprehensive mental health frameworks, especially for individuals residing near high-traffic areas.

Joint effects of air pollution and neighborhood socioeconomic status on cognitive decline - Mediation by depression, high cholesterol levels, and high blood pressure

Air pollution and neighborhood socioeconomic status (N-SES) are associated with adverse cardiovascular health and neuropsychiatric functioning in older adults. This study examines the degree to which the joint effects of air pollution and N-SES on the cognitive decline are mediated by high cholesterol levels, high blood pressure (HBP), and depression. In the Emory Healthy Aging Study, 14,390 participants aged 50+ years from Metro Atlanta, GA, were assessed for subjective cognitive decline using the cognitive function instrument (CFI). Information on the prior diagnosis of high cholesterol, HBP, and depression was collected through the Health History Questionnaire. Participants' census tracts were assigned 3-year average concentrations of 12 air pollutants and 16 N-SES characteristics. We used the unsupervised clustering algorithm Self-Organizing Maps (SOM) to create 6 exposure clusters based on the joint distribution of air pollution and N-SES in each census tract. Linear regression analysis was used to estimate the effects of the SOM cluster indicator on CFI, adjusting for age, race/ethnicity, education, and neighborhood residential stability. The proportion of the association mediated by high cholesterol levels, HBP, and depression was calculated by comparing the total and direct effects of SOM clusters on CFI. Depression mediated up to 87 % of the association between SOM clusters and CFI. For example, participants living in the high N-SES and high air pollution cluster had CFI scores 0.05 (95 %-CI:0.01,0.09) points higher on average compared to those from the high N-SES and low air pollution cluster; after adjusting for depression, this association was attenuated to 0.01 (95 %-CI:-0.04,0.05). HBP mediated up to 8 % of the association between SOM clusters and CFI and high cholesterol up to 5 %. Air pollution and N-SES associated cognitive decline was partially mediated by depression. Only a small portion (<10 %) of the association was mediated by HBP and high cholesterol.

Analysis of the situations and influencing factors of public anxiety in China: based on Baidu index data

Background

Anxiety disorders have emerged as one of the most prevalent mental health problems and health concerns. However, previous research has paid limited attention to measuring public anxiety from a broader perspective. Furthermore, while we know many factors that influence anxiety disorders, we still have an incomplete understanding of how these factors affect public anxiety. We aimed to quantify public anxiety from the perspective of Internet searches, and to analyze its spatiotemporal changing characteristics and influencing factors.

Methods

This study collected Baidu Index from 2014 to 2022 in 31 provinces in mainland China to measure the degree of public anxiety based on the Baidu Index from 2014 to 2022. The spatial autocorrelation analysis method was used to study the changing trends and spatial distribution characteristics of public anxiety. The influencing factors of public anxiety were studied using spatial statistical modeling methods.

Results

Empirical analysis shows that the level of public anxiety in my country has continued to rise in recent years, with significant spatial clustering characteristics, especially in the eastern and central-southern regions. In addition, we constructed ordinary least squares (OLS) and geographically weighted regression (GWR) spatial statistical models to examine the relationship between social, economic, and environmental factors and public anxiety levels. We found that the GWR model that considers spatial correlation and dependence is significantly better than the OLS model in terms of fitting accuracy. Factors such as the number of college graduates, Internet traffic, and urbanization rate are significantly positively correlated with the level of public anxiety.

Conclusion

Our research results draw attention to public anxiety among policymakers, highlighting the necessity for a more extensive examination of anxiety issues, especially among university graduates, by the public and relevant authorities.

Association and biological pathways between lung function and incident depression: a prospective cohort study of 280,032 participants

BACKGROUND

Lung health is increasingly recognized as an essential factor in mental health. However, prospective evidence on lung function with incident depression remains to be determined. The study aimed to examine the prospective association between impaired lung function and incident depression and the underlying biological mechanisms.

METHODS

This prospective cohort study comprised 280,032 non-depressed individuals with valid lung function measurements from the UK Biobank. Lung function was assessed through the forced vital capacity (FVC) or forced expiratory volume in 1 s (FEV1). Cox proportional hazard models were applied to estimate the associations between lung function and incident depression. Mediation analyses were fitted to investigate the potential mediating role of biomarkers and metabolites in the association.

RESULTS

A total of 9514 participants (3.4%) developed depression during a median follow-up of 13.91 years. Individuals in the highest quartile had a lower risk of depression (FVC % predicted: HR = 0.880, 95% CI = 0.830-0.933; FEV1% predicted: HR = 0.854, 95% CI = 0.805-0.905) compared with those in the lowest quartile of the lung function indices. Additionally, the restricted cubic splines suggested lung function indices had reversed J-shaped associations with incident depression (nonlinear P < 0.05 for FVC % predicted and FEV1% predicted). Impaired lung function yielded similar risk estimates (HR = 1.124, 95% CI = 1.074-1.176). Biomarkers involving systemic inflammation, erythrocytes, and liver and renal function may be potential mediators in the lung function-depression association.

CONCLUSIONS

This study revealed that the higher risk of developing depression was associated with impaired lung function. Also, the association might be partially mediated by biomarkers including systemic inflammation, erythrocytes, and liver and renal function, though these mediation findings should be interpreted with caution due to potential temporal ambiguity.

Trajectories of depressive symptom and its association with air pollution: evidence from the Mr. OS and Ms. OS Hong Kong cohort study

BACKGROUND

Depression is a global health priority. Maintaining and delaying depressive symptoms in older adults is a key to healthy aging. This study aimed to identify depressive symptom trajectories, predictors and mortality, while also exploring the relationship between air quality and depressive symptoms in older adults in the Hong Kong community over 14 years.

METHODS

This study is a longitudinal study in Hong Kong. The target population was community-dwelling older adults over age 65. Depressive symptoms were measured by the Geriatric Depression Scale (GDS-15). Group-based trajectory model was used to identify heterogeneity in longitudinal changes over 14 years and examine the associations between baseline variables and trajectories for different cohort members using multinomial logistic regression. The Kaplan-Meier method was employed to conduct survival analysis and explore the variations in survival probabilities over time among different trajectory group. Linear mixed model was used to explore the relationship between air quality and depressive symptoms.

RESULTS

A total of 2828 older adults were included. Three different trajectories of depressive symptoms in older people were identified: relatively stable (15.4%), late increase (67.1%) and increase (17.5%). Female, more number of chronic diseases, poor cognitive function, and poor health-related quality of life (HRQOL) were significantly associated with other less favorable trajectories compared with participants with stable levels of depressive symptoms. The late increase group had a lower mortality rate than the relatively stable and increased groups. Lower baseline ambient air pollutant exposure to NO2 over 14 years was significantly associated with fewer depressive symptoms.

CONCLUSIONS

In this study, we found that a late increase in depressive symptoms was the predominant trend in older Chinese people in Hong Kong. Poorer HRQOL was predictive of less favorable trajectories of depressive symptoms. Ambient air pollution was associated with depressive symptoms. This novel observation strengthens the epidemiological evidence of longitudinal changes in depressive symptoms and associations with late-life exposure to air pollution.

Utilizing daily excessive concentration hours to estimate small for gestational age infants attributable to fine particulate matter in Wuhan, China

Limited studies in China have explored the association between gravidae exposure to PM2.5 and small for gestational age infants (SGA), yielding inconsistent results. This study in Wuhan utilized daily excessive concentration hours (DECH) as a novel measure to assess PM2.5's impact on SGA. Data on air pollutants and pregnant women were collected from the Wuhan Municipal Ecology and Environmental Bureau and Wuhan Children's Hospital, respectively. Logistic regression models were employed to evaluate the contribution of PM2.5-DECH and PM2.5-mean to SGA. Significant correlations were observed between PM2.5-mean and SGA during the second trimester [OR = 1.23 (95% CI: 1.14-1.32)] and the entire pregnancy [OR = 1.15 (95% CI: 1.07-1.24)]. Similar correlations were found between PM2.5-DECH and SGA. These findings suggest that increased PM2.5 exposure is associated with a higher risk of SGA, and DECH may be used as a prospective substitute indicator for daily average concentration in similar studies.

Causal relationship between particulate matter and COVID-19 risk: A mendelian randomization study

Background

Observational studies have linked exposure to fine (PM2.5) and coarse (PM10) particulate matter air pollution with adverse COVID-19 outcomes, including higher incidence and mortality. However, some studies questioned the effect of air pollution on COVID-19 susceptibility, raising questions about the causal nature of these associations. To address this, a less biased method like Mendelian randomization (MR) is utilized, which employs genetic variants as instrumental variables to infer causal relationships in observational data.

Method

We performed two-sample MR analysis using public genome-wide association studies data. Instrumental variables correlated with PM2.5 concentration, PM2.5 absorbance, PM2.5-10 concentration and PM10 concentration were identified. The inverse variance weighted (IVW), robust adjusted profile score (RAPS) and generalized summary data-based Mendelian randomization (GSMR) methods were used for analysis.

Results

IVW MR analysis showed PM2.5 concentration [odd ratio (OR) = 3.29, 95% confidence interval (CI) 1.48-7.35, P-value = 0.0036], PM2.5 absorbance (OR = 5.62, 95%CI 1.98-15.94, P-value = 0.0012), and PM10 concentration (OR = 3.74, 95%CI 1.52-9.20, P-value = 0.0041) increased the risk of COVID-19 severity after Bonferroni correction. Further validation confirmed PM2.5 absorbance was associated with heightened COVID-19 severity (OR = 6.05, 95%CI 1.99-18.38, P-value = 0.0015 for RAPS method; OR = 4.91, 95%CI 1.65-14.59, P-value = 0.0042 for GSMR method) and hospitalization (OR = 3.15, 95%CI 1.54-6.47, P-value = 0.0018 for RAPS method). No causal links were observed between particulate matter exposure and COVID-19 susceptibility.

Conclusions

Our study established a causal relationship between smaller particle pollution, specifically PM2.5, and increased risk of COVID-19 severity and hospitalization. These findings highlight the importance of improving air quality to mitigate respiratory disease progression.

Long-term ambient ozone, omega-3 fatty acid, genetic susceptibility, and risk of mental disorders among middle-aged and older adults in UK biobank

BACKGROUND

Evidence linking ozone to depression and anxiety disorders remains sparse and results are heterogeneous. It remains unknown whether omega-3 fatty acid, or genetic susceptibility of mental disorders modify the impacts of ozone. The aim is to assess the associations of ambient ozone with depression and anxiety, and further explore the potential modification effects of omega-3 fatty acid and genetic susceptibility.

METHODS

In total of 257,534 participants were enrolled from 2006 to 2010 and followed up to 2016. Depression and anxiety were assessed using mental health questionnaires, primary care records and hospital admission records. The annual average concentrations of ozone were calculated and linked to individuals by home address. Dietary intake and plasma concentration were selected to reflect levels of omega-3 fatty acid. Polygenetic risk scores were selected to reflect genetic susceptibility. We examined the associations of ozone and incident mental disorders, and potential modification of omega-3 fatty acid and genetic susceptibility.

RESULTS

Incidences of depression (N = 6957) and anxiety (N = 6944) was associated with increase of ozone. Higher levels of omega-3 fatty acid might attenuate the ozone related depression risk. However, the modification effects of genetic susceptibility were not found.

CONCLUSIONS

Long-term exposure to ambient ozone increase the risk of mental disorders among the middle aged and older adults, and omega-3 fatty acid could reduce the adverse effects of ozone on mental health. Higher intake of omega-3 fatty acid is a potential strategy to prevent the risks caused by ozone on public mental health.

Joint association of heavy metals and polycyclic aromatic hydrocarbons exposure with depression in adults

BACKGROUND

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) represent significant components of environmental pollution, typically occurring as mixtures, raising concerns about their potential impact on human health. However, the combined effect of HMs and PAHs exposure on depression has not been explored.

METHODS

Leveraging National Health and Nutrition Examination Survey (NHANES) data spanning 2005 to 2016, we employ survey-weighted multiple logistic regression models to probe the interrelation between HMs, PAHs, and depression. This exploration is complemented by age and gender-stratified analyses, as well as a determination of the dose-response linkage via restricted cubic spline regression. Furthermore, the combined impact of HMs and PAHs on depression was evaluated through a range of statistical methodologies.

RESULTS

The study encompasses 7732 adults. Our findings unveil notable associations, indicating the significant influence of cadmium (Cd), lead (Pb), and all six PAHs metabolites on depression. Moreover, mixed exposure to HMs and PAHs emerges as a substantial contributor to an augmented depression risk, with Cd, Pb, 1-hydroxynaphthalene (1-NAP), 2-hydroxyfluorene (2-FLU), and 1-hydroxypyrene (1-PYR) likely driving this positive relationship. Intriguingly, subgroup analyses highlight greater prominence of these connections among individuals aged 20-59 and among women. Furthermore, the results tentatively suggest a potential interplay between Cd and 2-NAP in relation to depression.

CONCLUSION

This study posits that exposure to both individual and combined HMs and PAHs may be associated with an elevated risk of depression. Further prospective investigations are warranted to substantiate these findings.

How does air pollution threaten mental health? Protocol for a machine-learning enhanced systematic map

INTRODUCTION

Air pollution exposure has influenced a broad range of mental health conditions. It has attracted research from multiple disciplines such as biomedical sciences, epidemiology, neurological science, and social science due to its importance for public health, with implications for environmental policies. Establishing and identifying the causal and moderator effects is challenging and is particularly concerning considering the different mental health measurements, study designs and data collection strategies (eg, surveys, interviews) in different disciplines. This has created a fragmented research landscape which hinders efforts to integrate key insights from different niches, and makes it difficult to identify current research trends and gaps.

METHOD AND ANALYSIS

This systematic map will follow the Collaboration for Environmental Evidence's guidelines and standards and Reporting Standards for Systematic Evidence Syntheses guidelines. Different databases and relevant web-based search engines will be used to collect the relevant literature. The time period of search strategies is conducted from the inception of the database until November 2022. Citation tracing and backward references snowballing will be used to identify additional studies. Data will be extracted by combining of literature mining and manual correction. Data coding for each article will be completed by two independent reviewers and conflicts will be reconciled between them. Machine learning technology will be applied throughout the systematic mapping process. Literature mining will rapidly screen and code the numerous available articles, enabling the breadth and diversity of the expanding literature base to be considered. The systematic map output will be provided as a publicly available database.

ETHICS AND DISSEMINATION

Primary data will not be collected and ethical approval is not required in this study. The findings of this study will be disseminated through a peer-reviewed scientific journal and academic conference presentations.

Association of PM2.5 mass and its components with ovarian reserve in a northern peninsular province, China: The critical exposure period and components

BACKGROUND

A possible role of PM2.5 components on ovarian reserve has not been adequately unexplored.

OBJECTIVE

To evaluate the association between PM2.5 components and women' ovarian reserve over critical exposure periods in northern China, where the level of air pollution is among the nation's highest.

METHODS

We included 15,102 women with serum anti-Müllerian hormone (AMH) measurements from the Center for Reproductive Medicine of Shandong University during 2015-2019. Concentrations of PM2.5 and its five major components (0.1° × 0.1°), including sulfate, nitrate, ammonium, organic matter, and black carbon, were assigned to each residential address. Multivariable linear mixed effect models combined with constituent-residual models were performed to estimate the effect sizes of essential components over six short- to long-term exposure periods.

RESULTS

The strength of association was stronger during the process from primary to small antral follicle compared with other longer windows. For every interquartile range increase in PM2.5 mass was associated with - 8.7% (95%CI: -12.3%, -4.9%) change in AMH and the effect size was greatest for sulfate. Women with the lower level of attained education and those living inland were more susceptible compared with other population subgroups.

CONCLUSION

Exposure to specific components of air pollution during critical exposure windows is associated with a decline in ovarian reserve. These data add to the growing body of evidence that environmental factors have adverse effects on reproductive health, particularly for vulnerable population subgroups.

Role of metabolic risk factors in the relationship between ambient fine particulate matter and depressive symptoms: Evidence from a longitudinal population study

BACKGROUND

There is growing evidence indicating a connection between fine particulate matter (PM2.5) and depressive symptoms. Metabolic risk factors are critical determinants of depressive symptoms. However, the mediating role of these factors on the association between PM2.5 and depressive symptoms remains elusive. We aimed to investigate whether and to what extent metabolic risk factors mediated the link between long-term PM2.5 exposure and depressive symptoms.

METHODS

This study comprised 7794 individuals aged between 30 and 79 years who participated in two waves of the on-site surveys in the China Multi-Ethnic Cohort. Ambient PM2.5 concentrations were assessed utilizing a random forest method based on satellite data. We employed the Patient Health Questionnaire-9 to assess depressive symptoms at wave 2, and the overall as well as three sub-domain symptom scores (emotional, neurovegetative, and neurocognitive symptoms) were calculated. Three metabolic risk factors, including hypertension, diabetes, and dyslipidemia, were considered. Mediation analyses were conducted to assess the indirect effects of PM2.5 on depressive symptoms through metabolic risk factors.

RESULTS

We found a positive association between chronic exposure to ambient PM2.5 and overall depressive symptoms as well as the three sub-domains. In mediation analyses, metabolic risk factors partially mediated the associations of PM2.5 on depressive symptoms. The natural indirect effects (RR, 95% CI) of PM2.5 on overall, emotional, neurovegetative, and neurocognitive symptoms mediated through metabolic risk factors were 1.004(1.001, 1.007), 1.004 (1.001, 1.008), 1.004 (1.001, 1.007), and 1.003(0.999, 1.007), respectively. Larger indirect effects were found in elderly participants (mediated proportion, 29.3%), females (13.3%), and people who did not consume alcohol (19.6%).

CONCLUSIONS

Metabolic risk factors may act as mediators in the relationship between chronic PM2.5 exposure and depression. Treatment of metabolic risk factors may be an opportunity to reduce the burden of depression caused by long-term exposure to PM2.5.

Implications of Exposure to Air Pollution on Male Reproduction: The Role of Oxidative Stress

Air pollution, either from indoor (household) or outdoor (ambient) sources, occurs when there is presence of respirable particles in the form of chemical, physical, or biological agents that modify the natural features of the atmosphere or environment. Today, almost 2.4 billion people are exposed to hazardous levels of indoor pollution, while 99% of the global population breathes air pollutants that exceed the World Health Organization guideline limits. It is not surprising that air pollution is the world's leading environmental cause of diseases and contributes greatly to the global burden of diseases. Upon entry, air pollutants can cause an increase in reactive oxygen species (ROS) production by undergoing oxidation to generate quinones, which further act as oxidizing agents to yield more ROS. Excessive production of ROS can cause oxidative stress, induce lipid peroxidation, enhance the binding of polycyclic aromatic hydrocarbons (PAHs) to their receptors, or bind to PAH to cause DNA strand breaks. The continuous and prolonged exposure to air pollutants is associated with the development or exacerbation of pathologies such as acute or chronic respiratory and cardiovascular diseases, neurodegenerative and skin diseases, and even reduced fertility potential. Males and females contribute to infertility equally, and exposure to air pollutants can negatively affect reproduction. In this review, emphasis will be placed on the implications of exposure to air pollutants on male fertility potential, bringing to light its effects on semen parameters (basic and advanced) and male sexual health. This study will also touch on the clinical implications of air pollution on male reproduction while highlighting the role of oxidative stress.

Ambient air pollution and the dynamic transitions of stroke and dementia: a population-based cohort study

Background

Stroke and dementia are the leading causes of neurological disease burden. Detrimental effects of air pollution on both conditions are increasingly recognised, while the impacts on the dynamic transitions have not yet been explored, and whether critical time intervals exist is unknown.

Methods

This prospective study was conducted based on the UK Biobank. Annual average air pollution concentrations at baseline year 2010 estimated by land-use regression models were used as a proxy for long-term air pollution exposure. Associations between multiple air pollutants (PM2.5, PM2.5-10, and NO2) indicated by air pollution score and the dynamic transitions of stroke and dementia were estimated, and the impacts during critical time intervals were explored. The date cutoff of this study was February 29, 2020.

Findings

During a median follow-up of 10.9 years in 413,372 participants, 6484, 3813, and 376 participants developed incident stroke, dementia, and comorbidity of stroke and dementia. For the overall transition from stroke to comorbid dementia, the hazard ratio (HR) for each interquartile range (IQR) increase in air pollution score was 1.38 (95% CI, 1.15, 1.65), and the risks were limited to two time intervals (within 1 year and over 5 years after stroke). As for the transition from dementia to comorbid stroke, increased risk was only observed during 2-3 years after dementia.

Interpretation

Our findings suggested that air pollution played an important role in the dynamic transition of stroke and dementia even at concentrations below the current criteria. The findings provided new evidence for alleviating the disease burden of neurological disorders related to air pollution during critical time intervals.

Funding

The State Scholarship Fund of China Scholarship Council.