Effect of particulate air pollution and passive smoking on surrogate biomarkers of endothelial dysfunction in healthy children

Exposure to air pollution and cardiovascular risk in young children - a pilot project

OBJECTIVE

To examine relationships between traffic-related air pollution (TRAP) and markers of pre-clinical cardiovascular risk in young children.

STUDY DESIGN

We studied a cohort of healthy children ages 2-5 recruited from pediatric primary care sites (n = 122). We obtained child weight, height, blood pressure and hair nicotine levels. A blood sample was obtained for biomarkers of systemic inflammation, oxidation, and prevalence of circulating endothelial progenitor cells. This manuscript represents a secondary analysis. TRAP exposure (particulate levels, nitrogen dioxide, nitrogen oxides, and proximity to major roadways) was assessed using national air pollution data based on child's census tract of residence.

RESULTS

TRAP exposure had significant positive associations with prevalence of two of the three EPC subtypes (CD34 + /CD133 + /CD45- and CD133 + /CD45-) in unadjusted correlations. In a linear regression model, adjusting for sex, age, race, ethnicity, body mass index, parental education, child insurance, and secondhand smoke exposure, one EPC subtype (CD133 + /CD45-) had a positive significant correlation to every TRAP measure. No significant relationships between air pollution and measures of inflammation and oxidation was found.

CONCLUSION

Our findings of the upregulation of EPCs may signal a response to early vascular damage during early childhood due to air pollution exposure.

IMPACT

Traffic-related air pollution (TRAP) - known cardiovascular risk factor during adulthood Current pilot study in very young children shows upregulation of cells which protect the endothelial lining of blood vessels (endothelial progenitor cells, EPCs) Upregulation of EPCs aligns with other cardiovascular risks during childhood (obesity, prematurity, type 1 diabetes) Demonstrated with TRAP exposure lower than EPA threshold Response to air pollution may be protective of cardiovascular damage during early childhood.

Effect of PM2.5 exposure on adhesion molecules and systemic nitric oxide in healthy adults: The role of metals, PAHs, and oxidative potential

Since there is limited evidence on the impact of PM2.5 content on cardiovascular biomarkers, we conducted a cross-sectional study on 89 healthy adults from October 12 to November 21, 2021. We measured daily PM2.5 in two distinct regions during different time windows: a high-traffic urban area and an industrial suburb. The concentrations of metals, PAHs, and oxidative potential (OP) were determined using ICP-MS, GC-MS, and dithiothreitol (DTT), respectively. Systemic biomarkers, including NO, sICAM-1, sVCAM-1, MDA, and CRP, were quantified in each subject simultaneously. A generalized linear model was used to examine the association between PM2.5 toxicity and each health endpoint. Our findings indicated that daily PM2.5 concentrations exceeded the WHO-recommended level by approximately sevenfold. We found that PM2.5 exposure was associated with adverse cardiovascular outcomes. Moreover, exposure to PM2.5 mass, total PAHs, and certain trace metals (Ni, Fe, V, As, and Pb) resulted in a decline in serum NO levels. At lag 3, exposure to PM2.5 mass resulted in a significant decrease in NO levels [1.32% (95% CI: -2.27, -0.12)] and total PAHs [2.05% (95% CI: -3.93, -0.12)]. In contrast, OP exhibited a mild correlation with NO level increases. Positive associations were observed between PM2.5 and its chemical constituents (PAHs, As, Cu, OP) and adhesion molecules at different lag times. An increase of 0.16 ppb in PAH concentrations at an interquartile range was associated with a 4.74% decline (95% CI, -7.80, -0.55) in the sVCAM-1 level. However, our study did not reveal any significant trend between pollutants and other biomarkers (sICAM-1, MDA, and CRP). Consequently, our findings suggest that different PM2.5 chemical compositions exhibit diverse behavior in biological responses.

DNA methylation: a potential mediator between air pollution and metabolic syndrome

Given the global increase in air pollution and its crucial role in human health, as well as the steep rise in prevalence of metabolic syndrome (MetS), a better understanding of the underlying mechanisms by which environmental pollution may influence MetS is imperative. Exposure to air pollution is known to impact DNA methylation, which in turn may affect human health. This paper comprehensively reviews the evidence for the hypothesis that the effect of air pollution on the MetS is mediated by DNA methylation in blood. First, we present a summary of the impact of air pollution on metabolic dysregulation, including the components of MetS, i.e., disorders in blood glucose, lipid profile, blood pressure, and obesity. Then, we provide evidence on the relation between air pollution and endothelial dysfunction as one possible mechanism underlying the relation between air pollution and MetS. Subsequently, we review the evidence that air pollution (PM, ozone, NO₂ and PAHs) influences DNA methylation. Finally, we summarize association studies between DNA methylation and MetS. Integration of current evidence supports our hypothesis that methylation may partly mediate the effect of air pollution on MetS.

Air pollution exposure is associated with the gut microbiome as revealed by shotgun metagenomic sequencing

Animal work indicates exposure to air pollutants may alter the composition of the gut microbiota. This study examined relationships between air pollutants and the gut microbiome in young adults residing in Southern California. Our results demonstrate significant associations between exposure to air pollutants and the composition of the gut microbiome using whole-genome sequencing. Higher exposure to 24-hour O3 was associated with lower Shannon diversity index, higher Bacteroides caecimuris, and multiple gene pathways, including L-ornithine de novo biosynthesis as well as pantothenate and coenzyme A biosynthesis I. Among other pollutants, higher NO2 exposure was associated with fewer taxa, including higher Firmicutes. The percent variation in gut bacterial composition that was explained by air pollution exposure was up to 11.2% for O3 concentrations, which is large compared to the effect size for many other covariates reported in healthy populations. This study provides the first evidence of significant associations between exposure to air pollutants and the compositional and functional profile of the human gut microbiome. These results identify O3 as an important pollutant that may alter the human gut microbiome.

Longitudinal Associations Between Ambient Air Pollution With Insulin Sensitivity, β-Cell Function, and Adiposity in Los Angeles Latino Children

Evidence suggests that ambient air pollution (AAP) exposure may contribute to the development of obesity and type 2 diabetes. The objective of this study was to determine whether exposure to elevated concentrations of nitrogen dioxide (NO₂) and particulate matter with aerodynamic diameter <2.5 (PM_2.5) had adverse effects on longitudinal measures of insulin sensitivity (S_I), β-cell function, and obesity in children at high risk for developing diabetes. Overweight and obese Latino children (8-15 years; n = 314) were enrolled between 2001 and 2012 from Los Angeles, CA, and followed for an average of 3.4 years (SD 3.1 years). Linear mixed-effects models were fitted to assess relationships between AAP exposure and outcomes after adjusting for covariates including body fat percent. Higher NO₂ and PM_2.5 were associated with a faster decline in S_I and a lower S_I at age 18 years, independent of adiposity. NO₂ exposure negatively affected β-cell function, evidenced by a faster decline in disposition index (DI) and a lower DI at age 18 years. Higher NO₂ and PM_2.5 exposures over follow-up were also associated with a higher BMI at age 18 years. AAP exposure may contribute to development of type 2 diabetes through direct effects on S_I and β-cell function.

Short-term effects of particle size fractions on circulating biomarkers of inflammation in a panel of elderly subjects and healthy young adults

Systemic inflammation biomarkers have been associated with risk of cardiovascular morbidity and mortality. We aimed to clarify associations of acute exposure to particulate matter (PM₁₀ (PM < 10 μm), PM_2.5-10 (PM 2.5-10 μm), PM_2.5 (PM < 2.5 μm), PM_1-2.5 (PM 1-2.5 μm), and PM1 (PM < 1 μm)) with systemic inflammation using panels of elderly subjects and healthy young adults. We followed a panel of 44 nonsmoking elderly subjects living in a retirement home and a panel of 40 healthy young adults living in a school dormitory in Tehran city, Iran from May 2012 to May 2013. Blood biomarkers were measured one every 7-8 weeks and included white blood cells (WBC), high sensitive C-reactive protein (hsCRP), tumor necrosis factor-soluble receptor-II (sTNF-RII), interleukin-6 (IL-6), and von Willebrand factor (vWF). We measured hourly indoor and outdoor exposure to PM₁₀, PM_2.5-10, PM_2.5, PM_1-2.5, and PM₁ mass concentration to derive weighted averages of personal exposure based on simultaneously collected time-activity data. The random intercept linear mixed effects model was used for data analysis. We observed significant positive associations for WBC and IL-6 with exposure to PM₁₀, PM_2.5-10, PM_2.5, PM_1-2.5, and PM₁; sTNF-RII with PM_2.5, PM_1-2.5, and PM₁; hsCRP with PM_2.5 and PM₁; and vWF with PM₁₀ and PM_2.5-10, PM_2.5, and PM_1-2.5 mass concentration in elderly subjects from the current-day and multiday averages. For healthy young adults, we found significant positive associations for WBC and IL-6 with exposure to PM₁₀, PM_2.5-10, PM_2.5, and PM_1-2.5, but no with PM₁. The results showed that increase of hsCRP, sTNF-RII, and vWF were not significantly associated with any of the PM sizes investigated in the healthy young subjects. Our results provided some evidence that short-term exposure to PM₁₀, PM_2.5-10, PM_2.5, PM_1-2.5, and PM₁ was associated with inflammation and coagulation blood markers, but associations were depended on PM size and also differed across the various time lag.

Assessment of indoor and outdoor PM species at schools and residences in a high-altitude Ecuadorian urban center

An air monitoring campaign to assess children's environmental exposures in schools and residences, both indoors and outdoors, was conducted in 2010 in three low-income neighborhoods in Z1 (north), Z2 (central), and Z3 (southeast) zones of Quito, Ecuador - a major urban center of 2.2 million inhabitants situated 2850 m above sea level in a narrow mountainous basin. Z1 zone, located in northern Quito, historically experienced emissions from quarries and moderate traffic. Z2 zone was influenced by heavy traffic in contrast to Z3 zone which experienced low traffic densities. Weekly averages of PM samples were collected at schools (one in each zone) and residences (Z1 = 47, Z2 = 45, and Z3 = 41) every month, over a twelve-month period at the three zones. Indoor PM2.5 concentrations ranged from 10.6 ± 4.9 μg/m(3) (Z1 school) to 29.0 ± 30.5 μg/m(3) (Z1 residences) and outdoor PM2.5 concentrations varied from 10.9 ± 3.2 μg/m(3) (Z1 school) to 14.3 ± 10.1 μg/m(3) (Z2 residences), across the three zones. The lowest values for PM10-2.5 for indoor and outdoor microenvironments were recorded at Z2 school, 5.7 ± 2.8 μg/m(3) and 7.9 ± 2.2 μg/m(3), respectively. Outdoor school PM concentrations exhibited stronger associations with corresponding indoor values making them robust proxies for indoor exposures in naturally ventilated Quito public schools. Correlation analysis between the school and residential PM size fractions and the various pollutant and meteorological parameters from central ambient monitoring (CAM) sites suggested varying degrees of temporal relationship. Strong positive correlation was observed for outdoor PM2.5 at Z2 school and its corresponding CAM site (r = 0.77) suggesting common traffic related emissions. Spatial heterogeneity in PM2.5 concentrations between CAM network and sampled sites was assessed using Coefficient of Divergence (COD) analysis. COD values were lower when CAM sites were paired with outdoor measurements (<0.2) and higher when CAM and indoor values were compared (>0.2), suggesting that CAM network in Quito may not represent actual indoor exposures.

Respiratory health outcomes and air pollution in the Eastern Mediterranean Region: a systematic review

Exposure to air pollution can cause detrimental health and be an economic burden. With newly developed equipment, monitoring of different air pollutants, identifying the sources, types of air pollutants and their corresponding concentrations, and applying mitigation intervention techniques became a crucial step in public health protection. Countries in the Eastern Mediterranean Region (EMR) are highly exposed to dust storms, have high levels of particulate matter (PM) concentrations, and have a unique climatic as well as topographic and socio-economic structure. This is the first study conducted to systemically and qualitatively assess the health impacts of air pollution in the EMR, identify susceptible populations, and ascertain research and knowledge gaps in the literature to better inform decisions by policy makers. We screened relevant papers and reports published between 2000 and 2014 in research databases. A total of 36 published studies met the inclusion criteria. A variety of indoor and outdoor exposures associated with various acute and chronic respiratory health outcomes were included. Respiratory health outcomes ranged in severity, from allergies and general respiratory complaints to lung cancer and mortality. Several adverse health outcomes were positively associated with various indoor/outdoor air pollutants throughout the EMR. However, epidemiological literature concerning the EMR is limited to a few studies in a few countries. More research is needed to elucidate the health outcomes of air pollution. Standardized reliable assessments on the national level for various air pollutants in different regions should be implemented and made publically available for researchers to utilize in their research. Moreover, advancing and utilizing more sound epidemiological designs and studies on the effect of air pollution on the respiratory health outcomes is needed to portray the actual situation in the region.

The relationship of exposure to air pollutants in pregnancy with surrogate markers of endothelial dysfunction in umbilical cord

BACKGROUND

This study aims to investigate the association of exposure to ambient air pollution during pregnancy with cord blood concentrations of surrogate markers of endothelial dysfunction.

METHODS

This population-based cohort was conducted from March 2014 to March 2015 among 250 mother-neonate pairs in urban areas of Isfahan, the second large and air-polluted city in Iran. We analyzed the association between the ambient carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), particular matter 10 (PM10), and air quality index (AQI) with cord blood levels of endothelin-1, vascular adhesion molecule (VCAM), and intercellular adhesion molecule (ICAM). Multiple regression analysis was conducted after adjustment for potential confounding factors and covariates. The regression coefficient (beta), standard error of the estimate (SE), and 95% confidence intervals for each regression coefficient (95% CI) are reported.

RESULTS

Data of 233 mother-neonate pairs were complete, and included in the analysis. Multiple regression analyses showed that AQI, CO and O3 had significant correlation with cord blood ICAM-1 [Beta (SE), 95%CI: 2.93 (0.72), 1.33,5.54; 2.28(1.44), 1.56,5.12; and 2.02(0.01), 1.03,2.04, respectively] as well as with VCAM-1 [2.78(0.91), 1.69,4.57; 2.47(1.47), 1.43,5.37; and 2.01(0.01),1.07,2.04, respectively]. AQI, PM10, and SO2 were significantly associated with Endothelin-1 concentrations [Beta (SE), 95%CI: 10.16(5.08),7.61,14.28; 9.70(3.46), 2.88,16.52; and 1.07(0.02), 1.03,2.11, respectively].

CONCLUSIONS

The significant associations of air pollutants with markers of endothelial dysfunction during fetal period may provide another evidence on the adverse health effects of air pollutants on early stages of atherosclerosis from fetal period. Our findings underscore the importance of considering environmental factors in primordial prevention of chronic diseases.

A systematic review on the effects of environmental exposure to some organohalogens and phthalates on early puberty

Background:

Early puberty is a common worldwide problem. Different parameters as genetics, metabolic diseases, obesity, as well as environmental factors may affect the age of puberty. This systematic review aims to survey the related literature on the effects of environmental pollutants and especially organohalogens and phthalates on early puberty.

Materials and Methods:

A systematic review of papers published in the English language was completed in January 2014. Studies on the associations of organohalogens and phthalates with the puberty time were included. A literature search was conducted in EMBASE, PubMed, Scopus, ISI Web of Science, and Cochrane Library from 1995 to January 2014; moreover manual search through references of relevant manuscripts was considered. The literature search identified 212 papers, of which 13 papers fulfilled the inclusion criteria of the current study. Two reviewers independently identified relevant papers for potential inclusion and assessed the methodological quality.

Results:

This review included 6572 participants in nine countries from three continents (Europe, North America, and Asia). Different studies determined the effects of pollutants on maturation signs and pubertal stages and confirmed the association of organohalogens and phthalates with early puberty.

Conclusion:

Based on the studied literature, environmental pollutants surround and accumulate in human societies and their adverse health effects are well documented. It can be concluded that organohalogens and phthalates are disturbing the normal process of puberty timing; especially their influence on early maturation in girls should be underscored.

Targeting Household Air Pollution for Curbing the Cardiovascular Disease Burden: A Health Priority in Sub-Saharan Africa

Household air pollution (HAP) is a major public health problem, particularly in sub-Saharan Africa where most of the populations still rely on solid fuels for cooking, heating, and lighting. This narrative review highlights the direct and indirect evidence of the important role of HAP in cardiovascular disease, especially in sub-Saharan African countries where highest rates of major cardiovascular disease and death are observed, and thus provides ample reason for promotion of preventive interventions to reduce HAP exposures in the region. There is an urgent need for efficient strategies to educate populations on the health issues associated with this health hazard, to provide affordable clean cooking energy for poor people and to promote improved household ventilation. High-quality data on household energy practices and patterns of HAP and related health issues are still needed for efficient policy making in this region.

Residential exposure to urban traffic is associated with increased carotid intima-media thickness in children

Chronic exposure to urban traffic pollution is documented to promote atherosclerosis in adults but little is known about its potential effects in children. Our study examined the association of long-term exposure to traffic with carotid intima-media thickness (cIMT) in 287 healthy children. Residential proximity and distance-weighted traffic density (DWTD) were used as proximity markers for traffic-related air pollution exposure. The multivariable analyses revealed that children residing <100 meters from the nearest heavily trafficked road had cIMT mean and maximum measurements that were increased by 15% and 11% compared to those living ≥ 200 meters away (P = 0.0001). Similar increases in cIMT were identified for children in the highest versus lowest DWTD tertile. Children who resided 100–199 meters from traffic or in the middle DWTD tertile also exhibited increased cIMT but these differences were not statistically significant. No statistically significant differences were identified between residential distance to traffic or DWTD and systemic inflammation indicators (CRP, IL-6). The study results suggest that exposure to urban traffic promotes arterial remodeling in children. This finding is important since even small increases in cIMT over time can potentially lead to earlier progression to atherosclerosis. It is also important because traffic-related pollution is potentially modifiable.

Personal exposure to particulate matter and inflammation among patients with periodontal disease

The association between particulate air pollution and high-sensitivity C-reactive protein (hs-CRP) has been well documented in epidemiological studies. Periodontitis has been linked to elevated hs-CRP levels in recent studies. It is still unknown whether patients with periodontal infections are more susceptible to particulate air pollution. The aim of this study was to investigate whether particles with aerodynamic diameters of less than 2.5 μm (PM2.5) had greater effects on increasing hs-CRP among patients with periodontal infections compared to periodontally healthy individuals. We conducted a cross-sectional study on two panels of adult subjects, 100 adult patients with chronic periodontitis and 100 periodontally healthy adults, in order to evaluate the association between particulate matter (PM) and hs-CRP. We collected blood samples from each subject, measured hs-CRP and monitored average exposure to PM2.5 over 24h four times during 2010 to 2012. We used mixed-effects models to estimate the association between PM2.5 and hs-CRP and adjusted for cardiovascular risk factors. We found that a 10 μg/m(3) increase in PM2.5 was associated with a 3.22% (95% confidence interval, CI: 1.21, 5.23; p<0.01) increase in hs-CRP among all adult subjects. The effect of PM2.5 in patients was significantly higher than the effect in healthy participants. In the healthy adult panel, a 10 μg/m(3) increase in PM2.5 was associated with a 1.17% (95% CI: 0.54, 1.80; p<0.01) increase in hs-CRP. For adults in the patient group, a 10 μg/m(3) increase in PM2.5 was associated with a 9.62% (95% CI: 7.05, 12.19; p<0.01) increase in hs-CRP. We concluded that personal exposure to PM2.5 was associated with increases in hs-CRP among adult subjects. The presence of periodontal disease led to a considerably increased effect magnitude by more than eight fold.

Is air quality index associated with cardiometabolic risk factors in adolescents? The CASPIAN-III Study

OBJECTIVE

This study aims to evaluate the association of air quality index (AQI) with cardiometabolic risk factors in a nationally representative sample of healthy adolescents.

METHODS

This nationwide survey was conducted among a stratified multi-stage probability sample of students, aged 10-18 years, from 27 provinces of Iran. Those students with history of any acute or chronic diseases, any medication use, as well as active or passive smoking were not included to the current study. Dietary and physical activity habits were documented by valid questionnaires. Physical examination and blood sampling were conducted under standard protocols. AQI data were obtained from air pollution monitoring sites from the entire country by considering air pollutants concentration, which includes all provincial counties containing different clusters.

RESULTS

The study participants consisted of 1413 students (48.8% boys) with a mean (SD) age of 14.81±2.48 years. The mean AQI level was 285.37±30.11 at national levels. After adjustment for confounding factors including age, sex, and anthropometric measures, as well as for dietary and physical activity habits, multiple linear regressions based on correlation of coefficients of the AQI with cardiometabolic risk factors showed significant positive correlations of AQI with systolic blood pressure, fasting blood glucose, total cholesterol, LDL-cholesterol, and triglycerides, as well as significant negative correlations with HDL-cholesterol. After adjustment for abovementioned confounding factors, binary logistic regressions analyses showed that AQI increased the risk of abnormal levels of some risk factors as elevated levels of systolic blood pressure, total cholesterol, and triglycerides.

CONCLUSION

The associations of low air quality with some cardiometabolic factors in the current survey, although not strong, might be considered as an evidence of the adverse cardiometabolic consequences of exposure to air pollutants in the pediatric age group, and predisposing them to earlier development of non-communicable diseases.

First report on the association of drinking water hardness and endothelial function in children and adolescents

INTRODUCTION

This study aims to investigate the relationship of water hardness and its calcium and magnesium content with endothelial function in a population-based sample of healthy children and adolescents.

MATERIAL AND METHODS

This case-control study was conducted in 2012 among 90 individuals living in two areas with moderate and high water hardness in Isfahan County, Iran. The flow-mediated dilatation (FMD) of the brachial artery and the serum levels of soluble adhesion molecules (sICAM-1, sVCAM-1) were measured as surrogate markers of endothelial function, and high-sensitivity C-reactive protein (hs-CRP), as a marker of inflammation.

RESULTS

Data of 89 participants (51% boys, mean age 14.75 (2.9) years) were complete. Those participants living in the area with high water hardness had higher FMD, hs-CRP, and soluble adhesion molecules (sICAM-1, sVCAM-1) than their counterparts living in the area with moderate water hardness. Multiple linear regression analysis showed that after adjustment for confounding factors of age, gender, body mass index, healthy eating index and physical activity level, total water hardness, as well as water content of calcium and magnesium, had a significant positive relationship with FMD. The corresponding associations were inverse and significant with soluble adhesion molecules (p < 0.05).

CONCLUSIONS

This study, which to the best of our knowledge is the first of its kind in the pediatric age group, suggests that water hardness, as well as its calcium and magnesium content, may have a protective role against early stages of atherosclerosis in children and adolescents.