Effects of long-term exposure to ambient fine particulate matter and its specific components on blood pressure and hypertension incidence

Exposure to low concentrations of PM2.5 and its constituents with preterm birth in Shenzhen, China: a retrospective cohort study

BACKGROUND

Due to the Air Pollution Prevention and Control Measures issued by the Chinese government, air quality has significantly improved, particularly with respect to PM2.5. However, studies on the relationship between low concentrations of PM2.5 and preterm birth (PTB) remain limited in China.

OBJECTIVE

To examine the associations between low concentrations of PM2.5 and its constituents and PTB.

METHODS

This retrospective cohort study was conducted from July 2021 to April 2023 in Shenzhen, China. Data on questionnaires and pregnancy outcomes were collected for each participant. Using the Tracking Air Pollution in China (TAP) dataset, we assessed the concentrations of PM2.5 and its chemical constituents, including sulfate (SO42-), nitrate (NO3-), organic matter (OM), black carbon (BC), and ammonium (NH4+). We applied a generalized additive model (GAM) to evaluate the relationship. The relationship between exposure to PM2.5 and its constituents and PTB was further examined using a method that combined dummy variable settings with trend tests. Stratified analysis was conducted to explore the potential factors.

RESULTS

Among 17,240 live-born infants, the rate of PTB was 6.0%, and the average exposure concentration of PM2.5 was 20.24 μg/m3. There were positive associations between PM2.5 and its constituents and PTB. With each interquartile range (IQR) increase in PM2.5 during the third trimester, the risk of PTB increased by 2.23 times. The exposure effects of sulfate (SO42-) and organic matter (OM) were comparable to the total PM2.5. The third trimester might be the critical susceptibility window. The risk was higher among women who conceived in the cold season and were exposed to higher temperatures during pregnancy.

CONCLUSION

Even at low levels, PM2.5 can still increase the risk of PTB, with varying health effects attributed to different constituents. This underscores the importance of further strengthening environmental management and characterizing the contributions of PM2.5 sources.

Carbonaceous cores serve as surrogates for environmental particulate matter inducing vascular endothelial inflammation via inflammasome activation

Ambient particulate matter (PM) exposure is a known risk factor for cardiovascular diseases. Epidemiological studies have shown the association between PM exposure and vascular complications, including vasculitis, embolism, hypertension, stroke, and atherosclerosis. However, the exact mechanisms underlying its vascular toxicity, especially in relation to short-term exposures, remain incompletely understood. This study investigates the role of PM and its carbonaceous cores in driving vascular endothelial inflammation via inflammasome activation. We hypothesized that PM SRM1648a exposure induces vascular endothelial inflammation through oxidative stress and inflammasome activation. Short-term exposure to PM SRM1648a was assessed in BALB/c mice for systemic inflammation and oxidative stress biomarkers, alongside in vitro studies in HUVECs and EA.hy926 endothelial cells to elucidate inflammasome activation pathways. PM SRM1648a exposure significantly altered redox balance and cytokine profiles in mice and upregulated NLRP3/NLRC4 inflammasomes in vascular endothelial cells, leading to caspase-1/IL-1β activation. Intriguingly, pyroptosis was not the primary mode of cell death. In vitro studies demonstrated that antioxidants glutathione monoethyl ester effectively mitigated oxidative stress and inflammasome activation in endothelial cells. This study highlights the critical role of ROS-mediated inflammasome activation in vascular inflammation induced by PM SRM1648a, with carbon-based cores as key contributors.

Black Carbon Air Pollution and Incident Mortality Among the Advance-Aged Adults in China: A Prospective Cohort Study

BACKGROUND

We aimed to assess associations between black carbon (BC) and nonaccidental mortality among advance-aged adults in China.

METHODS

We conducted a prospective cohort study in 22 provinces of Chinese Longitudinal Healthy Longevity Survey. We calculated concentrations of 3-year average BC, fine particulate matter (PM2.5), and other PM2.5 components (SO42-, NO3-, NH4+, and organic matter) at individual levels. We used Cox proportional hazards models to assess dose-response BC exposure on nonaccidental mortality, adjusted for total PM2.5, green space, temperature, humidity, and demographic covariates.

RESULTS

We studied 12 873 participants, with a median age of 88 years and 57.4% females. For a median follow-up of 4 years, we observed 7 426 mortality events. The mean 3-year average BC and total PM2.5 exposure concentrations were 3.49 and 66.97 μg/m3, respectively. An increase of 1 μg/m3 in BC was associated with a 39% increase in mortality risks (HR: 1.39, 95% CI: 1.36, 1.43), notably higher than the corresponding increase in mortality risks linked to total PM2.5 (HR: 1.003, 95% CI: 1.002, 1.004) in the adjusted model. The stratified analyses show that people living in rural areas, with lower social and leisure activity index, and lower physical activity, were at greater risk from BC exposure.

CONCLUSIONS

BC is a strong predictor of mortality, with a higher effect estimate compared with total PM2.5 and other PM2.5 components, particularly in rural populations. Although total PM2.5 has been a target indicator of clean air policy interventions, our results indicate that BC concentration should be routinely measured, reported, and studied to improve public health.

Effects of PM2.5 components on hypertension and diabetes: Assessing the mitigating influence of green spaces

BACKGROUND

Particulate matter with diameters ≤2.5 μm (PM2.5) is a significant air pollutant associated with hypertension and diabetes. However, the specific contributions of its components and their joint exposure with green spaces remain poorly understood, especially in developing regions.

OBJECTIVES

This study aims to investigate the individual and joint impacts of PM2.5 and its components on the middle-aged and older adults, identify primary risk factors, and assess disease risks associated with simultaneous exposure to green spaces.

METHOD

We conducted a prospective cohort study in Tianjin from 2014 to 2021, involving individuals aged ≥45 years. Satellite-based machine learning models quantified PM2.5 components, including black carbon (BC), organic matter (OM), sulfate (SO42-), nitrate (NO3-), ammonium (NH4+), and chloride (Cl-). Residential greenness was assessed using the Normalized Difference Vegetation Index (NDVI). A time-varying Cox proportional hazards model analyzed associations between PM2.5 components and the incidence of hypertension and diabetes. The quantile g-computation model evaluated joint exposure effects and relative contributions of the components. Pollutants and NDVI were dichotomized using median values and combined to create a joint exposure model, aimed at exploring the potential effects of NDVI. Stratified analyses were performed to identify vulnerable subpopulations.

RESULTS

Over 241,528.73 person-years of follow-up, there were 15,747 (38.34 %) new cases of hypertension and 8945 (13.59 %) new cases of diabetes. Each standard deviation (SD) increase in OM was associated with increased incidence of hypertension (hazard ratio: 1.609; 95 % confidence interval: 1.583, 1.636) and diabetes (1.484; 1.453, 1.515). Joint exposure to components is linked to higher incidence of hypertension and diabetes, with OM identified as the primary contributor. The joint exposure model indicated elevated population risk in areas with low NDVI and high PM2.5 concentrations, particularly affecting males and individuals younger than 60 years.

CONCLUSIONS

Long-term exposure to higher levels of PM2.5 components is significantly associated with increased hypertension and diabetes, with OM potentially being the primary contributor. Joint exposure to green space may mitigate these risks. These findings highlight how PM2.5 sources impact health, informing more effective governance measures.

Association of residential greenness exposures on disability: Findings from the cohort study on global AGEing and Adult Health (SAGE) in China

BACKGROUND

With the accelerating population ageing globally, disability has become a major public concern. Residential greenness may be one of the influencing factors of disability, but epidemiological evidence in the associations of residential greenness exposures with disability is limited. We aimed to investigate the associations of residential greenness exposures with the risk of disability in the elderly.

METHODS

Data of 8408 residents were obtained from the World Health Organization Study on Global AGEing and Adult Health (WHO SAGE) implemented in China during 2007-2018. Participants were matched to the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) at their residential address. Disability was measured by the 12-item Chinese version of the World Health Organization Disability Assessment Schedule (WHODAS 2.0). The associations were examined using a generalized linear mixed model with stratified analyses by the covariates.

RESULTS

We observed significantly negative associations of greenness exposures with the summary WHODAS score [NDVI500m: -0.290, 95% Confidence Intervals (95%CI): -0.510, -0.070; EVI500m: -0.453, 95%CI: -0.757, -0.149], and with the score of cognition (EVI500m: -0.472, 95%CI: -0.881, -0.063), mobility (NDVI500m: -0.632, 95%CI: -0.965, -0.299; EVI500m: -0.739, 95%CI: -1.199, -0.280), and participation (NDVI500m: -0.388, 95%CI: -0.651, -0.125; EVI500m: -0.530, 95%CI: -0.893, -0.166). People living alone had a more pronounced association in cognition (NDVI500m: -1.546, 95%CI: -2.471, -0.621). The associations with summary WHODAS score were stronger among participants living in rural areas (NDVI500m: -0.420, 95%CI: -0.683, -0.157), having less education level (NDVI500m: -0.618, 95%CI: -0.982, -0.253), and living in northern China (NDVI500m: -0.381, 95%CI: -0.776, 0.013).

CONCLUSIONS

Residential greenness may reduce the onset and worsening of disability, particularly for domains of cognition, mobility, and social participation. Because of its stronger influence among people with low socioeconomic status, increasing greenness levels in areas with lower socioeconomic status may promote health equity.

Association of PM2.5 exposure in early pregnancy and maternal liver function: A retrospective cohort study in Shenzhen, China

OBJECTIVE

Studies have shown that fine particulate matter (PM2.5) has adverse effects on the liver function, but epidemiological evidence is limited, especially regarding pregnant women. This study aims to investigate the association between PM2.5 exposure in early pregnancy and maternal liver function during pregnancy.

METHODS

This retrospective cohort study included 13,342 pregnant participants. PM2.5 and Ozone (O3) exposure level, mean temperature, and relative humidity for each participant were assessed according to their residential address. The levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TBIL) were measured during the second and third trimesters. Data on PM2.5 and O3 exposure level were sourced from Tracking Air Pollution in China (TAP), while the mean temperature and relative humidity were obtained from the ERA5 dataset. The Generalized Additive Model (GAM) was used to analyze the associations between PM2.5 exposure and maternal liver function during pregnancy, adjusting for potential confounding factors.

RESULTS

According to the results, each 10 μg/m3 increase in PM2.5 was associated with an increase of 3.57% (95% CI: 0.29%, 6.96%) in ALT and 4.25% (95% CI: 2.33%, 6.21%) in TBIL during the second trimester and 4.51% (95% CI: 2.59%, 6.47%) in TBIL during the third trimester, respectively. After adjusting for O3, these associations remained significant, and the effect of PM2.5 on ALT during the second trimester was further strengthened. No significant association observed between PM2.5 and AST.

CONCLUSIONS

PM2.5 exposure in early pregnancy is associated with increasement of maternal ALT and TBIL, suggesting that PM2.5 exposure may have an adverse effect on maternal liver function. Although this finding indicates an association between PM2.5 exposure and maternal liver function, more research is needed to confirm our findings and explore the underlying biological mechanisms.

Elevated serum uric acid levels mediate the associations of ambient PM2.5 and its components with glaucoma

Limited epidemiological information exists on the relationships between fine particulate matter (PM2.5) components and glaucoma risk. Moreover, the potential mediation effect of serum uric acid (UA) levels remains unexplored. Data from the China Health and Retirement Longitudinal Survey (CHARLS) spanning 2011-2020 were analyzed. Cox proportional hazard models and quantile-based g-computation (qg-computation) models were applied to determine the associations of PM2.5 and its five components (including sulfate [SO₄2⁻], nitrate [NO₃⁻], ammonium [NH₄⁺], organic matter [OM], and black carbon [BC]) with glaucoma risk. A causal mediation model was applied to assess the mediation effect of serum UA. Individual exposure to PM2.5 mass and its five components was positively associated with glaucoma risk, respectively. The mixture of PM2.5 components were significantly and positively associated with glaucoma risk (hazard ratio [HR] = 1.31, 95% confidence interval [CI]: 1.18-1.45), with NH₄⁺ and BC contributing the most (proportions: 81% and 19%, respectively). These associations were modified by sex and residence. Elevated serum UA levels played a mediated role in the association between PM2.5 mass and its five chemical components and glaucoma, with mediated proportions ranging from 12% to 15%. Prolonged exposure to PM2.5 components, especially NH4+ and BC, may elevate the glaucoma risk among Chinese middle-aged and older people, and elevated serum UA levels may play a key mediating role.

Particulate Matter-Induced Emerging Health Effects Associated with Oxidative Stress and Inflammation

Environmental pollution continues to increase with industrial development and has become a threat to human health. Atmospheric particulate matter (PM) was designated as a Group 1 carcinogen by the International Agency for Research on Cancer in 2013 and is an emerging global environmental risk factor that is a major cause of death related to cardiovascular and respiratory diseases. PM is a complex composed of highly reactive organic matter, chemicals, and metal components, which mainly cause excessive production of reactive oxygen species (ROS) that can lead to DNA and cell damage, endoplasmic reticulum stress, inflammatory responses, atherosclerosis, and airway remodeling, contributing to an increased susceptibility to and the exacerbation of various diseases and infections. PM has various effects on human health depending on the particle size, physical and chemical characteristics, source, and exposure period. PM smaller than 5 μm can penetrate and accumulate in the alveoli and circulatory system, causing harmful effects on the respiratory system, cardiovascular system, skin, and brain. In this review, we describe the relationship and mechanism of ROS-mediated cell damage, oxidative stress, and inflammatory responses caused by PM and the health effects on major organs, as well as comprehensively discuss the harmfulness of PM.

Effects of long-term exposure to air pollutant mixture on blood pressure in typical areas of North China

BACKGROUND

Studies about the combined effects of gaseous air pollutants and particulate matters are still rare.

OBJECTIVES

This study was performed based on baseline survey of the Diverse Life-Course Cohort in the Beijing-Tianjin-Hebei (BTH) Region of North China to evaluate the association of long-term air pollutants with blood pressure and the combined effect of the air pollutants mixture among 32821 natural han population aged 20 years or above.

METHODS

Three-year average exposure to air pollutants (PM10, PM2.5, PM1, O3, SO2, NO2, and CO) and PM2.5 components [black carbon (BC), ammonium (NH4+), nitrate (NO3-), sulfate (SO42-), and organic matter (OM)] of residential areas were calculated based on well-validated models. Generalized linear mixed models (GLMMs) were used to estimate the associations of air pollutants exposure with the systolic blood pressure (SBP), diastolic blood pressure (DBP), Mean arterial pressure (MAP), pulse pressure (PP) and prevalent hypertension. Quantile g-Computation and Bayesian Kernel Machine Regression (BKMR) were employed to assess the combined effect of the air pollutant mixture.

RESULTS

We found that long-term exposures of O3, PM2.5, and PM2.5 components were stably and strongly associated with elevated SBP, DBP, and MAP and prevalent hypertension. O3 increased SBP, DBP, and MAP at a similar extent, but with greater effects; while, PM2.5 and PM2.5 components had a greater impact on SBP than DBP, which increased PP simultaneously. In multi-pollutant models, the combined effects of the air pollutant mixture on blood pressure and prevalent hypertension was predominantly influenced by O3, PM2.5, and O3, OM in different models, respectively. For example, O3, PM2.5 contributed 57.25 %, 39.22 % of the positive combined effect of the air pollutant mixture on SBP; and O3, OM positively contributed 70.00 %, 30.00 % on prevalent hypertension, respectively. There were interactions between O3, CO, SO2 and PM2.5 components on hbp, SBP and PP.

CONCLUSIONS

The results showed positive associations of air pollutant mixtures with blood pressure, where O3 and PM2.5 (especially OM) might be primary contributors. There were interactions between gaseous air pollutants and PM2.5 components on blood pressure and prevalent hypertension.

Global associations between long-term exposure to PM2.5 constituents and health: A systematic review and meta-analysis of cohort studies

Existing studies on the most impactful component remain controversial, hindering the optimization of future air quality standards that concerns particle composition. We aimed to summarize the health risk associated with PM2.5 components and identify those components with the greatest health risk. We performed a meta-analysis to quantify the combined health effects of PM2.5 components, and used the meta-smoothing to produce the pooled concentration-response (C-R) curves. Out of 8954 initial articles, 80 cohort studies met the inclusion criteria, including a total of 198.08 million population. The pooled C-R curves demonstrated approximately J-shaped association between total mortality and exposure to BC, and NO3-, but U-shaped and inverted U-shaped relationship withSO42- and OC, respectively. In addition, this study found that exposure to various elements, including BC,SO42-NO3-, NH4+, Zn, Ni, and Si, were significantly associated with an increased risk of total mortality, with Ni presenting the largest estimate. And exposure to NO3-, Zn, and Si was positively associated with an increased risk of respiratory mortality, while exposure to BC, SO42-, and NO3- showed a positive association with risk of cardiovascular mortality. For health outcome of morbidity, BC was notably associated with a higher incidence of asthma, type 2 diabetes and stroke. Subgroup analysis revealed a higher susceptibility to PM2.5 components in Asia compared to Europe and North America, and females showed a higher vulnerability. Given the significant health effects of PM2.5 components, governments are advised to introduce them in regional monitoring and air quality control guidelines. ENVIRONMENTAL IMPLICATION: PM2.5 is a complex mixture of chemical components from various sources, and each component has unique physicochemical properties and uncertain toxicity, posing significant threat to public health. This study systematically reviewed cohort studies on the association between long-term exposure to 13 PM2.5 components and the risk of morbidity and mortality. And we applied the meta-smoothing approach to establish the pooled concentration-response associations between PM2.5 components and mortality globally. Our findings will provide strong support for PM2.5 components monitoring and the improvement of air quality-related regulations. This will aid in helping to enhance health intervention strategies and mitigating public exposure to detrimental particulate matter.

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.

Sex differences and dietary patterns in the association of air pollutants and hypertension

BACKGROUND

Hypertension is one of the major public health problems in China. Limited evidence exists regarding sex differences in the association between hypertension and air pollutants, as well as the impact of dietary factors on the relationship between air pollutants and hypertension. The aim of this study was to investigate the sex-specific effects of dietary patterns on the association between fine particulate matter (PM2.5), ozone(O3) and hypertension in adults residing in Jiangsu Province of China.

METHODS

A total of 3189 adults from the 2015 China Adult Chronic Disease and Nutrition Surveillance in Jiangsu Province were included in this study. PM2.5 and O3 concentrations were estimated using satellite space-time models and assigned to each participant. Dietary patterns were determined by reduced rank regression (RRR), and multivariate logistic regression was used to assess the associations of the obtained dietary patterns with air pollutants and hypertension risk.

RESULTS

After adjusting for confounding variables, we found that males were more sensitive to long-term exposure to PM2.5 (Odds ratio (OR) = 1.42 95%CI:1.08,1.87), and females were more sensitive to long-term exposure to O3 (OR = 1.61 95%CI:1.15,2.23). Traditional southern pattern identified through RRR exhibited a protective effect against hypertension in males (OR = 0.73 95%CI: 0.56,1.00). The results of the interaction between dietary pattern score and PM2.5 revealed that adherence to traditional southern pattern was significantly associated with a decreased risk of hypertension in males (P < 0.05), while no significant association was observed among females.

CONCLUSIONS

Our findings suggested that sex differences existed in the association between dietary patterns, air pollutants and hypertension. Furthermore, we found that adherence to traditional southern pattern may mitigate the risk of long-term PM2.5 exposure-induced hypertension in males.