Short-Term Exposure to Air Pollution and Biomarkers of Oxidative Stress: The Framingham Heart Study

Air pollution exposure and risk of adverse obstetric and neonatal outcomes among women with type 1 diabetes

AIMS/HYPOTHESIS

Women with type 1 diabetes have increased risk for poor obstetric outcomes. Prenatal air pollution exposure is also associated with adverse outcomes for women and infants. We examined whether women with type 1 diabetes are more vulnerable than other women to pollution-associated risks during pregnancy.

METHODS

In singleton deliveries from the Consortium on Safe Labor (2002-2008), obstetric and neonatal outcomes were compared for women with type 1 diabetes (n = 507) and women without autoimmune disease (n = 204,384). Preconception, trimester, and whole pregnancy average air pollutant exposure (ozone (O₃), carbon monoxide (CO), particulate matter >10 μm (PM₁₀), PM > 2.5 μm (PM_2.5), sulfur dioxide (SO₂), nitrogen oxides (NO_x)) were estimated using modified Community Multiscale Air Quality models. Poisson regression models with diabetes*pollutant interaction terms estimated relative risks and 95% confidence intervals for adverse outcomes, adjusted for maternal characteristics and geographic region.

RESULTS

For whole pregnancy exposure to SO₂, women with type 1 diabetes had 15% increased risk (RR:1.15 95%CI:1.01,1.31) and women without autoimmune disease had 5% increased risk (RR:1.05 95%CI:1.05,1.06) for small for gestational age birth (p_interaction = 0.09). Additionally, whole pregnancy O₃ exposure was associated with 10% increased risk (RR:1.10 95%CI:1.02,1.17) among women with type 1 diabetes and 2% increased risk (RR:1.02 95%CI:1.00,1.04) among women without autoimmune disease for perinatal mortality (p_interaction = 0.08). Similar patterns were observed between PM_2.5 exposure and spontaneous preterm birth.

CONCLUSIONS

Pregnant women with type 1 diabetes may be at greater risk for adverse outcomes when exposed to air pollution than women without autoimmune disease.

Ambient PM2.5 species and ultrafine particle exposure and their differential metabolomic signatures

BACKGROUND

The metabolomic signatures of short- and long-term exposure to PM_2.5 have been reported and linked to inflammation and oxidative stress. However, little is known about the relative contribution of the specific PM_2.5 species (hence sources) that drive these metabolomic signatures.

OBJECTIVES

We aimed to determine the relative contribution of the different species of PM_2.5 exposure to the perturbed metabolic pathways related to changes in the plasma metabolome.

METHODS

We performed mass-spectrometry based metabolomic profiling of plasma samples among men from the Normative Aging Study to identify metabolic pathways associated with PM_2.5 species. The exposure windows included short-term (one, seven-, and thirty-day moving average) and long-term (one year moving average). We used linear mixed-effect regression with subject-specific intercepts while simultaneously adjusting for PM_2.5, NO₂, O₃, temperature, relative humidity, and covariates and correcting for multiple testing. We also used independent component analysis (ICA) to examine the relative contribution of patterns of PM_2.5 species.

RESULTS

Between 2000 and 2016, 456 men provided 648 blood samples, in which 1158 metabolites were quantified. We chose 305 metabolites for the short-term and 288 metabolites for the long-term exposure in this analysis that were significantly associated (p-value < 0.01) with PM_2.5 to include in our PM_2.5 species analysis. On average, men were 75.0 years old and their body mass index was 27.7 kg/m². Only 3% were current smokers. In the adjusted models, ultrafine particles (UFPs) were the most significant species of short-term PM_2.5 exposure followed by nickel, vanadium, potassium, silicon, and aluminum. Black carbon, vanadium, zinc, nickel, iron, copper, and selenium were the significant species of long-term PM_2.5 exposure. We identified several metabolic pathways perturbed with PM_2.5 species including glycerophospholipid, sphingolipid, and glutathione. These pathways are involved in inflammation, oxidative stress, immunity, and nucleic acid damage and repair. Results were overlapped with the ICA.

CONCLUSIONS

We identified several significant perturbed plasma metabolites and metabolic pathways associated with exposure to PM_2.5 species. These species are associated with traffic, fuel oil, and wood smoke. This is the largest study to report a metabolomic signature of PM_2.5 species' exposure and the first to use ICA.

Ambient fine particulate matter exposure and incident mild cognitive impairment and dementia

BACKGROUND/OBJECTIVE

Poor air quality is implicated as a risk factor for cognitive impairment and dementia. Few studies have examined these associations longitudinally in well-characterized population-based cohorts with standardized annual assessment of both mild cognitive impairment (MCI) and dementia. We investigated the association between estimated ambient fine particulate matter (PM_2.5 ) and risk of incident MCI and dementia in a post-industrial region known for historically poor air quality.

SETTING/PARTICIPANTS

Adults aged 65+ years in a population-based cohort (n = 1572).

MEASUREMENTS

Census tract level PM_2.5 from Environmental Protection Agency (EPA) air quality monitors; Clinical Dementia Rating (CDR)®.

DESIGN

We estimated ambient PM_2.5 exposure (μg/m³ , single-year and 5-year averages) by geocoding participants' residential addresses to census tracts with daily EPA PM_2.5 measurements from 2002 to 2014. Using Bayesian spatial regression modeling adjusted for age, sex, education, smoking history, and household income, we examined the association between estimated PM_2.5 exposure and risk of incident MCI (CDR = 0.5) and incident dementia (CDR ≥ 1.0).

RESULTS

Modeling estimated single-year exposure, each 1 μg/m³ higher ambient PM_2.5 was associated with 67% higher adjusted risk of incident dementia (hazard ratio [HR] = 1.669, 95% credible interval [CI]: 1.298, 2.136) and 75% higher adjusted risk of incident MCI (HR = 1.746, 95% CI: 1.518, 2.032). Estimates were higher when modeling 5-year ambient PM_2.5 exposure for incident dementia (HR = 2.082, 95% CI: 1.528, 3.015) and incident MCI (HR = 3.419, 95% CI: 2.806, 4.164).

CONCLUSIONS

Higher estimated ambient PM_2.5 was associated with higher risk of incident MCI and dementia, particularly when considering longer-term exposure, and independent of demographic characteristics and smoking history. Targeting poor air quality may be a reasonable population-wide intervention to reduce the risk of cognitive impairment in older adults, particularly in regions exceeding current recommendations for safe exposure to PM_2.5 .

Traffic-related air pollution is associated with glucose dysregulation, blood pressure, and oxidative stress in children

BACKGROUND

Metabolic syndrome increases the risk of cardiovascular disease in adults. Antecedents likely begin in childhood and whether childhood exposure to air pollution plays a contributory role is not well understood.

OBJECTIVES

To assess whether children's exposure to air pollution is associated with markers of risk for metabolic syndrome and oxidative stress, a hypothesized mediator of air pollution-related health effects.

METHODS

We studied 299 children (ages 6-8) living in the Fresno, CA area. At a study center visit, questionnaire and biomarker data were collected. Outcomes included hemoglobin A1c (HbA1c), urinary 8-isoprostane, systolic blood pressure (SBP), and BMI. Individual-level exposure estimates for a set of four pollutants that are constituents of traffic-related air pollution (TRAP) - the sum of 4-, 5-, and 6-ring polycyclic aromatic hydrocarbon compounds (PAH456), NO₂, elemental carbon, and fine particulate matter (PM_2.5) - were modeled at the primary residential location for 1-day lag, and 1-week, 1-month, 3-month, 6-month, and 1-year averages prior to each participant's visit date. Generalized additive models were used to estimate associations between each air pollutant exposure and outcome.

RESULTS

The study population was 53% male, 80% Latinx, 11% Black and largely low-income (6% were White and 3% were Asian/Pacific Islander). HbA1c percentage was associated with longer-term increases in TRAP; for example a 4.42 ng/m³ increase in 6-month average PAH456 was associated with a 0.07% increase (95% CI: 0.01, 0.14) and a 3.62 μg/m³ increase in 6-month average PM_2.5 was associated with a 0.06% increase (95% CI: 0.01, 0.10). The influence of air pollutants on blood pressure was strongest at 3 months; for example, a 6.2 ppb increase in 3-month average NO₂ was associated with a 9.4 mmHg increase in SBP (95% CI: 2.8, 15.9). TRAP concentrations were not significantly associated with anthropometric or adipokine measures. Short-term TRAP exposure averages were significantly associated with creatinine-adjusted urinary 8-isoprostane.

DISCUSSION

Our results suggest that both short- and longer-term estimated individual-level outdoor residential exposures to several traffic-related air pollutants, including ambient PAHs, are associated with biomarkers of risk for metabolic syndrome and oxidative stress in children.

Short and long term exposure to air pollution increases the risk of ischemic heart disease

Previous studies have suggested an increased risk of ischemic heart disease related to air pollution. This study aimed to explore both the short-term and long-term effects of air pollutants on the risk of ischemic heart disease after adjusting for meteorological factors. The Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2013 was used. Overall, 2155 participants with ischemic heart disease and 8620 control participants were analyzed. The meteorological data and air pollution data, including SO₂ (ppm), NO₂ (ppm), O₃ (ppm), CO (ppm), and particulate matter (PM)₁₀ (μg/m³), were analyzed using conditional logistic regression. Subgroup analyses were performed according to age, sex, income, and region of residence. One-month exposure to SO₂ was related to 1.36-fold higher odds for ischemic heart disease (95% confidence interval [95% CI] 1.06–1.75). One-year exposure to SO₂, O₃, and PM₁₀ was associated with 1.58- (95% CI 1.01–2.47), 1.53- (95% CI 1.27–1.84), and 1.14 (95% CI 1.02–1.26)-fold higher odds for ischemic heart disease. In subgroup analyses, the ≥ 60-year-old group, men, individuals with low income, and urban groups demonstrated higher odds associated with 1-month exposure to SO₂. Short-term exposure to SO₂ and long-term exposure to SO_2, O₃, and PM₁₀ were related to ischemic heart disease.

Personal PM2.5 exposure and lung function: Potential mediating role of systematic inflammation and oxidative damage in urban adults from the general population

BACKGROUND

Short-term effects of fine particulate matter (PM_2.5) exposure on lung function have been reported. However, few studies have assessed PM_2.5 exposure on the personal level, and the mechanism underlying the effects of PM_2.5 exposure on lung function remains less clear.

OBJECTIVES

To evaluate the association between personal PM_2.5 exposure and lung function alteration in general population and to explore the roles of systematic inflammation and oxidative damage in this association.

METHODS

A total of 7685 lung function tests were completed among 4697 urban adults in Wuhan, China. Plasma C-reactive protein (CRP), urinary 8-iso-prostaglandin-F_2α (8-iso-PGF_2α) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were measured. Personal PM_2.5 exposure levels were estimated using an estimation model from the actual measurements of individual PM_2.5 levels in 191 participants. Mixed linear models were used to evaluate the association between personal PM_2.5 exposure and lung function. Mediation analyses were conducted to investigate the roles of CRP, 8-iso-PGF_2α and 8-OHdG in above associations.

RESULTS

After adjusting for confounders, each 10 μg/m³ increase in the previous-day personal PM_2.5 exposure was associated with 2.94 mL, 2.02 mL and 16.14 mL/s decreases in forced vital capacity (FVC), forced expiration volume in 1 s (FEV₁) and peak expiratory flow, respectively. The associations were more obvious among never smokers compared with current smokers. Cumulative 7-day exposure to PM_2.5 led to the strongest adverse effects on lung function. Among never smokers with high PM_2.5 exposure levels, a positive relationship was observed between personal PM_2.5 level and urinary 8-iso-PGF_2α, and 8-iso-PGF_2α meditated 4.69% and 12.30% of the association between the 7-day moving PM_2.5 concentration and FVC and FEV₁, respectively. We did not observe a significant positive association between PM_2.5 exposure and plasma CRP or urinary 8-OHdG.

CONCLUSION

Short-term personal exposure to PM_2.5 is associated with reduced pulmonary ventilation function. Urinary 8-iso-PGF_2α partly mediates these associations.

Association between airborne particulate matter and renal function: An analysis of 2.5 million young adults

BACKGROUND

Limited studies have examined the impact of airborne particulate matter of 2.5 μm or less (PM_2.5) on renal function. No study has examined the effect of PM₁, which is small enough to reach the blood circulation. We examined whether exposure to PM₁ or PM_2.5 affected renal function of young Han Chinese.

METHOD

We included 2,546,047 young adults who were aged 18 to 45 years, being Han ethnicity and had no chronic disease from a Chinese national birth cohort. Serum creatinine (Scr) of each participant was measured during the baseline examination. Estimated glomerular filtration rate (eGFR) were calculated for each participant using the latest Chronic Kidney Disease Epidemiology Collaboration equation. One-year average exposure to PM₁ and PM_2.5 prior to the health examination for each participant were estimated using machine learning models with satellite remote sensing information. Generalized additive mixed models were used to estimate associations between PM₁ or PM_2.5 and renal function after adjusting for detailed individual variables.

RESULTS

A 10 μg/m³ increment in PM₁ exposure was associated with -0.95% (95%CI: -1.04%, -0.87%) difference of eGFR in females and -0.37% (95%CI: -0.44%, -0.31%) in males. For PM_2.5, the corresponding difference of eGFR was -0.99% (95%CI: -1.05%, -0.93%) in females and -0.48% (95%CI: -0.53%, -0.43%) in males, respectively. Associations between eGFR and PM were higher in females compared to males (p < 0.05 for interaction test). Association with PM₁ were weaker than that with other fractions included in PM_2.5. Participants who worked as farmers, were of normal weight, were not exposed to tobacco smoking, did not drink alcohol, had higher associations between eGFR and PM than their counterparts (p < 0.05 for interaction test).

CONCLUSION

Exposure to PM₁ and PM_2.5 was associated with reduced renal function among Han Chinese at reproductive age.

Longitudinal associations between household solid fuel use and depression in middle-aged and older Chinese population: A cohort study

BACKGROUND

Previous studies found that ambient air pollution was associated with a higher prevalence of depressive symptoms. However, the longitudinal associations between household solid fuel use, which is the main source of household air pollution, and depressive symptoms remain unclear. This cohort study aimed to explore the associations between household solid fuel use and incidence of depressive symptoms in China.

METHODS

In total, 8637 participants were enrolled in this prospective cohort study. Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depression Scale. The associations between baseline household solid fuel use and the incidence of depressive symptoms were examined using Cox proportional hazards regression models.

RESULTS

During the 4-year of follow-up, 2074 of 8637 participants developed depressive symptoms. Compared with participants who used clean fuel for both heating and cooking, the multivariate-adjusted hazard ratio (HR) (95% confidence intervals [95% CI]) for depressive symptoms incidence in participants who used solid fuels for two purposes (cooking and heating) was 1.15 (1.01, 1.31). In the solid fuel use subgroup analysis, use of solid fuels for cooking (HR, 1.12; 95% CI, 1.02-1.24) was associated with a higher incidence of depressive symptoms after adjustments while use for heating (HR, 1.05; 95% CI, 0.93-1.18) was not. Moreover, compared with persistent solid fuel users, switching from solid to clean fuels for cooking resulted in a lower risk of depressive symptoms before adjustments (HR, 0.82; 95% CI, 0.71-0.95) and a non-significant association (HR, 0.90; 95% CI, 0.77-1.04) afterwards.

CONCLUSIONS

The results suggest that household solid fuel use for cooking was associated with a higher incidence of depressive symptoms. Preventive strategies based on improving household cooking environment for depressive symptoms should be established.

The association between air pollution and hospitalization for patients with systemic lupus erythematosus in Chile: A daily time series analysis

Genetic and environmental factors are thought to influence the activity of systemic lupus erythematosus (SLE), but relatively little is known about the effects of ambient air pollution. Using pollution data from air monitoring stations in the urban centers in Santiago Chile, along with daily patient hospitalization data from 2001 to 2012, an association between ambient air pollution and daily hospital admissions for SLE was tested using generalized linear models. Averaged over all regions pollutant mean 24 h concentrations were: 0.96 ppm carbon monoxide (CO), 64 ppb ozone (O₃), 43 ppb nitrogen dioxide (NO₂), 9 ppb sulphur dioxide (SO₂), 29 μg/m³ particulate matter ≤ 2.5 μm in mean aerodynamic diameter (PM_2.5), and 67 μg/m³ particulate matter ≤ 10 μm in diameter (PM₁₀). The relative risk estimates in single pollutant models for an interquartile range (IQR) increase in pollutant were: RR = 1.34 (95% CI: 1.06-1.83) for SO₂, RR = 1.60 (95% CI: 1.15-2.24) for CO, and RR = 1.41 (95% CI: 1.14-1.86) for PM_2.5. In two-pollutant models, the significance of SO₂ and PM_2.5 persisted despite adjustments for each of the other measured pollutants. These findings suggest that acute increases in air pollution increase the risk of hospitalization with a primary diagnosis of SLE.

Protocol to assess the efficacy of carnosine supplementation in mitigating the adverse cardiovascular responses to particulate matter (PM) exposure: the Nucleophilic Defense Against PM Toxicity (NEAT) trial

INTRODUCTION

Exposure to airborne particulate matter (PM) is associated with cardiovascular disease. These outcomes are believed to originate from pulmonary oxidative stress and the systemic delivery of oxidised biomolecules (eg, aldehydes) generated in the lungs. Carnosine is an endogenous di-peptide (β-alanine-L-histidine) which promotes physiological homeostasis in part by conjugating to and neutralising toxic aldehydes. We hypothesise that an increase of endogenous carnosine by dietary supplementation would mitigate the adverse cardiovascular outcomes associated with PM exposure in humans.

METHODS AND ANALYSIS

To test this, we designed the Nucleophilic Defense Against PM Toxicity trial. This trial will enroll 240 participants over 2 years and determine if carnosine supplementation mitigates the adverse effects of PM inhalation. The participants will have low levels of endogenous carnosine to facilitate identification of supplementation-specific outcomes. At enrollment, we will measure several indices of inflammation, preclinical cardiovascular disease and physical function. Participants will be randomly allocated to carnosine or placebo groups and instructed to take their oral supplement for 12 weeks with two return clinical visits and repeated assessments during times of peak PM exposure (June-September) in Louisville, Kentucky, USA. Statistical modelling approaches will be used to assess the efficacy of carnosine supplementation in mitigating adverse outcomes.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Institutional Review Board at the University of Louisville. Results from this study will be disseminated at scientific conferences and in peer-reviewed publications.Trial registration: NCT03314987; Pre-results.

Heavy metals exposure, lipid peroxidation and heart rate variability alteration: Association and mediation analyses in urban adults

Exposure to heavy metals was reported to be associated with heart rate variability (HRV) alteration. However, possible pathway of such association remains unclear. In this research, we investigated the possible role of lipid peroxidation in the associations between urinary heavy metals and HRV. We performed a cross-sectional study using baseline data of Wuhan-Zhuhai cohort. Urinary heavy metals (including lead, barium, antimony, cadmium, zinc, copper, iron and manganese), urinary 8-iso-prostaglandin-F2α levels (common biomarker for lipid peroxidation) and HRV indices (SDNN, r-MSSD, low frequency, high frequency and total power) were measured among 3022 participants. We conducted multivariable linear regression models to quantify associations between urinary 8-iso-prostaglandin-F2α (8-iso-PGF2α) and heavy metals or HRV indices. The potential role of 8-iso-PGF2α in the association of urinary heavy metals with HRV was evaluated through mediation analyses. After adjusting for potential confounders, urinary manganese, iron, copper, zinc, cadmium, antimony and barium were identified to be negatively associated with one or more HRV parameters. Each one-unit growth of log-transformed levels of urinary manganese, iron, copper, zinc, antimony and barium was associated with a 1.9%, 1.5%, 4.7%, 4.0%, 2.7% and 1.3% decrease in SDNN, respectively. We observed positive dose-response relationships between all eight urinary heavy metals and 8-iso-PGF2α, as well as negative association of urinary 8-iso-PGF2α with SDNN and total power (all P trend<0.05). The proportions mediated by 8-iso-PGF2α on SDNN were 4.6% for manganese, 9.3% for iron, 19.8% for antimony and 11.0% for barium. The proportions mediated by 8-iso-PGF2α on total power were 6.9% for manganese and 10.1% for cadmium (all P value < 0.05). This study suggested that urinary manganese, iron, copper, zinc, cadmium, antimony and barium were negatively associated with HRV indices. Lipid peroxidation may partly mediate the associations of urinary manganese, iron, cadmium, antimony and barium with specific HRV indices.

Attributable risks associated with hospital outpatient visits for mental disorders due to air pollution: A multi-city study in China

AIM

To determine the associations between outdoor air pollution and hospital outpatient visits for mental disorders in China.

METHODS

We obtained data of 111,842 hospital outpatient visits for mental disorders from the largest hospitals of 13 cities, China, between January 01, 2013 and December 31, 2015. We collected air pollutant data including particulate matter ≤2.5 µm in diameter (PM_2.5), particulate matter ≤10 µm in diameter (PM₁₀), nitrogen dioxide (NO₂), ozone (O₃) and sulphur dioxide (SO₂) from China National Environmental Monitoring Centre during the same period. We conducted a time-stratified case-crossover design with conditional logistic regression models to determine the associations.

RESULTS

A 10 µg/m³ increase in PM_2.5, PM₁₀, NO₂ and SO₂ was associated with a significant increase in hospital outpatient visits for mental disorders on the current day. When stratified by age, sex and season, the effects of PM_2.5 and NO₂ were robust among different subgroups at lag05 days. PM₁₀ showed positive associations in males, in cold season, and in depression patients. SO₂ showed positive associations in males, in cold season, and in anxiety patients. O₃ showed positive associations in females, in warm season, and in depression patients. Nearly one sixth hospital outpatient visits for mental disorders can be attributable to NO₂.

CONCLUSIONS

Short-term increase in PM_2.5, PM₁₀, NO₂, SO₂ and O₃ concentrations was significantly associated with exacerbation of mental disorders in China as indicated by increases in hospital outpatient visits. NO₂ had more serious health threat than other pollutants in terms of mental disorders. Our findings strongly suggest a need for more strict emission control regulations to protect mental health from air pollution.

Effects of particulate matter on atherosclerosis: a link via high-density lipoprotein (HDL) functionality?

BACKGROUND

Exposure to air pollution has been associated with adverse effects on human health, and ultimately increased morbidity and mortality. This is predominantly due to hazardous effects on the cardiovascular system. Exposure to particulate matter (PM) is considered to be responsible for the most severe effects.

MAIN BODY

Here we summarize current knowledge from existing epidemiological, clinical and animal studies on the influence of PM exposure on high-density lipoprotein (HDL) functionality and the potential initiation and progression of atherosclerosis. We highlight experimental studies that bring support to the causality and point to possible mechanistic links. Recent studies indicate that the functional properties of HDL are more important than the levels per se. Fine (PM_2.5-0.1) and ultrafine (UFP) PM are composed of chemicals as well as biological elements that are redox-active and may trigger pro-inflammatory responses. Experimental studies indicate that these properties and responses may promote HDL dysfunction via oxidative pathways. By affecting protein and lipid components of the HDL particle, its anti-atherosclerotic characteristics including cholesterol efflux capacity, as well as other anti-oxidative and anti-inflammatory features might be impaired.

CONCLUSION

Current literature suggests that PM promotes HDL dysfunction via oxidative pathways. However, as relatively few studies so far have evaluated the impact of particulate air pollution on HDL functionality, more human epidemiological as well as experimental studies are needed to strengthen any possible causal relationship and determine any relevance to atherosclerosis.

Ambient air pollution and cause-specific risk of hospital admission in China: A nationwide time-series study

BACKGROUND

The impacts of air pollution on circulatory and respiratory systems have been extensively studied. However, the associations between air pollution exposure and the risk of noncommunicable diseases of other organ systems, including diseases of the digestive, musculoskeletal, and genitourinary systems, remain unclear or inconclusive. We aimed to systematically assess the associations between short-term exposure to main air pollutants (fine particulate matter [PM2.5] and ozone) and cause-specific risk of hospital admission in China over a wide spectrum of human diseases.

METHODS AND FINDINGS

Daily data on hospital admissions for primary diagnosis of 14 major and 188 minor disease categories in 252 Chinese cities (107 cities in North China and 145 cities in South China) from January 1, 2013, to December 31, 2017, were obtained from the Hospital Quality Monitoring System of China (covering 387 hospitals in North China and 614 hospitals in South China). We applied a 2-stage analytic approach to assess the associations between air pollution and daily hospital admissions. City-specific associations were estimated with quasi-Poisson regression models and then pooled by random-effects meta-analyses. Each disease category was analyzed separately, and the P values were adjusted for multiple comparisons. A total of 117,338,867 hospital admissions were recorded in the study period. Overall, 51.7% of the hospitalized cases were male, and 71.3% were aged <65 years. Robust positive associations were found between short-term PM2.5 exposure and hospital admissions for 7 major disease categories: (1) endocrine, nutritional, and metabolic diseases; (2) nervous diseases; (3) circulatory diseases; (4) respiratory diseases; (5) digestive diseases; (6) musculoskeletal and connective tissue diseases; and (7) genitourinary diseases. For example, a 10-μg/m3 increase in PM2.5 was associated with a 0.21% (95% CI 0.15% to 0.27%; adjusted P < 0.001) increase in hospital admissions for diseases of the digestive system on the same day in 2-pollutant models (adjusting for ozone). There were 35 minor disease categories significantly positively associated with same-day PM2.5 in both single- and 2-pollutant models, including diabetes mellitus, anemia, intestinal infection, liver diseases, gastrointestinal hemorrhage, renal failure, urinary tract calculus, chronic ulcer of skin, and back problems. The association between short-term ozone exposure and respiratory diseases was robust. No safety threshold in the exposure-response relationships between PM2.5 and hospital admissions was observed. The main limitations of the present study included the unavailability of data on personal air pollution exposures.

CONCLUSIONS

In the Chinese population during 2013-2017, short-term exposure to air pollution, especially PM2.5, was associated with increased risk of hospitalization for diseases of multiple organ systems, including certain diseases of the digestive, musculoskeletal, and genitourinary systems; many of these associations are important but still not fully recognized. The effect estimates and exposure-response relationships can inform policy making aimed at protecting public health from air pollution in China.

Markers involved in proinflammatory effects by environmental toxicants

Toxicological studies have identified polycyclic aromatic hydrocarbons (PAH) in human breast milk, smoked and barbequed food, although the largest contribution of PAH intake into the body are cereals and cereals products. The major effects attributable to PAH appeared to occur in the liver, lungs, the hematopoietic system, and the kidney. Nevertheless, more precise mechanisms by which PAH initiates its pathological features are not fully understood. In the present study, we evaluated levels of myeloperoxidase activity, its association with nitric oxide synthesis (NO), levels of uric acid (UA) in circulating blood and glucose in female rats exposed to environmental toxicants. A higher concentration of hydrogen peroxide activates myeloperoxidase, which acts as a leucocyte attractant, contributing to enhanced iNOS activity. In parallel, uric acid in addition to its pro-inflammatory effects aggravates insulin resistance and hyperglycemia, which worsens the process. Our findings suggest potential intermediate mechanisms involved in the inflammatory effects of PAH, which might give insight for the involvement of environmental toxicants not only in carcinogenesis but also in its association with acute cardiovascular disease and induction of multi-organ damage. The development of iNOS inhibitors might be beneficial in certain inflammatory disorders.

Effects of prenatal exposure to NO2 on children's neurodevelopment: a systematic review and meta-analysis

The neurotoxicity of NO₂ exposure is well-known and potentially causes impaired of neural functions. This review aimed to estimate associations between prenatal NO₂ exposure and neurodevelopment for children. Articles published until May 2019 reported prenatal NO₂ exposure and children's cognition, psychomotor, language, attention, IQ, and behavior function were searched according to all related terms. The main databases we retrieved included PubMed, Web of Science, Embase, and Cochrane Library. Coefficient was extracted, conversed, and synthesized by random effects meta-analysis. Meanwhile, qualitatively describe would be used for some studies which cannot be synthesized quantitatively for lack of quantity or methods inconsistency. Finally, a total of 3848 citations were searched, and only 10 studies were included. We estimated that per 10 μg/m³ increase of NO₂ during pregnancy was associated with a - 0.76 point decrease in global psychomotor (95% CI, - 1.34, - 0.18) and a - 0.62 point decrease in fine psychomotor for children (95% CI, - 1.09, - 0.16). But no significant association found in general cognitive and language. In addition, through the literature review, it seemed that prenatal exposure to NO₂ might cause adverse impacts on children's attention, IQ, and different behaviors, but this requires confirmation from further researches. Our study indicated that prenatal exposure to NO₂ seems to be associated with impaired neural development for children, especially for fine psychomotor. However, further studies are needed for determining the effects of prenatal air pollution exposure on attention, IQ, and behavior.

Cigarette Smoke Exposure and Radiographic Pulmonary Vascular Morphology in the Framingham Heart Study

Rationale: Cigarette smoke exposure is a risk factor for many lung diseases, and histologic studies suggest that tobacco-related vasoconstriction and vessel loss plays a role in the development of emphysema. However, it remains unclear how tobacco affects the pulmonary vasculature in general populations with a typical range of tobacco exposure, and whether these changes are detectable by radiographic methods. Objectives: To determine whether tobacco exposure in a generally healthy population manifests as lower pulmonary blood vessel volumes and vascular pruning on imaging. Methods: A total of 2,410 Framingham Heart Study participants with demographic data and smoking history underwent volumetric whole-lung computed tomography from 2008 to 2011. Automated algorithms calculated the total blood volume of all intrapulmonary vessels (TBV), smaller peripheral vessels (defined as cross-sectional area <5 mm² [BV5]), and the relative fraction of small vessels (BV5/TBV). Tobacco exposure was assessed as smoking status, cumulative pack-years, and second-hand exposure. We constructed multivariable linear regression models to evaluate associations of cigarette exposure and pulmonary blood vessel volume measures, adjusting for demographic covariates, including age, sex, height, weight, education, occupation, and median neighborhood income. Results: All metrics of tobacco exposure (including smoking status, pack-years, and second-hand exposure) were consistently associated with higher absolute pulmonary blood vessel volume, higher small vessel volume, and/or higher small vessel fraction. For example, ever-smokers had a 4.6 ml higher TBV (95% confidence interval [CI] = 2.9-6.3, P < 0.001), 2.1 ml higher BV5 (95% CI = 1.3-2.9, P < 0.001), and 0.28 percentage-point-higher BV5/TBV (95% CI = 0.03-0.52, P = 0.03) compared with never-smokers. These associations remained significant after adjustment for percent predicted forced expiratory volume in 1 second, cardiovascular comorbidities, and did not differ based on presence or absence of airflow obstruction. Conclusions: Using computed tomographic imaging, we found that cigarette exposure was associated with higher pulmonary blood vessel volumes, especially in the smaller peripheral vessels. Although, histologically, tobacco-related vasculopathy is characterized by vessel narrowing and loss, our results suggest that radiographic vascular pruning may not be a surrogate of these pathologic changes.

Oxidative stress pathways of air pollution mediated toxicity: Recent insights

Ambient air pollution is a leading environmental cause of morbidity and mortality globally with most of the outcomes of cardiovascular origin. While numerous mechanisms are proposed to explain the link between air pollutants and cardiovascular events, the evidence supports a role for oxidative stress as a critical intermediary pathway in the transduction of systemic responses in the cardiovascular system. Indeed, alterations in vascular function are a critical step in the development of cardiometabolic disorders such as hypertension, diabetes, and atherosclerosis. This review will provide an overview of the impact of particulate and gaseous pollutants on oxidative stress from human and animal studies published in the last five years. We discuss current gaps in knowledge and evidence to date implicating the role of oxidative stress with an emphasis on inhalational exposures. We conclude with the identification of gaps, and an exhortation for further studies to elucidate the impact of oxidative stress in air pollution mediated effects.

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Particulate matter air pollution is the leading risk factor for cardiovascular morbidity and mortality globally.

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Mechanisms of oxidative stress mediated pathways.

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How does lung inflammation crucial to inhalational exposure mediate systemic toxicity?

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Review of recent animal and human exposure studies providing insights into oxidative stress pathways.

Exposure to ambient fine particulate matter is associated with changes in fasting glucose and lipid profiles: a nationwide cohort study

BACKGROUND

Ambient fine particulate matter is a rising concern for global public health. It was recently suggested that exposure to fine particulate matter may contribute to the development of diabetes and dyslipidaemia. This study aims to examine the potential associations of ambient particulate matter exposure with changes in fasting glucose and lipid profiles in Koreans.

METHOD

We used the data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC), a nationwide database representative of the Korean population. A total of 85,869 individuals aged ≥20 years were included. Multiple regression analyses were conducted to assess the associations between exposure to particulate matter and changes in fasting glucose and lipid profiles at 2-year intervals after adjusting for confounders.

RESULTS

Significant associations were observed between an increase in interquartile range for particulate matter < 2.5 μm in diameter (PM_2.5) and elevated levels of fasting glucose and low-density lipoprotein cholesterol (p for trend = 0.015 and 0.010, respectively), while no association for particulate matter sized 2.5-10 μm in diameter (PM_10-2.5) was noted after adjusting for the other covariates. Sub-group analyses showed stronger associations in individuals who were older (≥60 years) or physically inactive.

CONCLUSIONS

Fine particulate matter exposure affects worsening fasting glucose and low-density lipoprotein cholesterol levels, with no evidence of an association for coarse particulate matter.

Air pollution and cardiovascular disease: car sick

The cardiovascular effects of inhaled particle matter (PM) are responsible for a substantial morbidity and mortality attributed to air pollution. Ultrafine particles, like those in diesel exhaust emissions, are a major source of nanoparticles in urban environments, and it is these particles that have the capacity to induce the most significant health effects. Research has shown that diesel exhaust exposure can have many detrimental effects on the cardiovascular system both acutely and chronically. This review provides an overview of the cardiovascular effects on PM in air pollution, with an emphasis on ultrafine particles in vehicle exhaust. We consider the biological mechanisms underlying these cardiovascular effects of PM and postulate that cardiovascular dysfunction may be implicated in the effects of PM in other organ systems. The employment of multiple strategies to tackle air pollution, and especially ultrafine particles from vehicles, is likely to be accompanied by improvements in cardiovascular health.

Exposure to airborne fine particulate matter is associated with impaired endothelial function and biomarkers of oxidative stress and inflammation

Epidemiological evidence suggests that exposure to air pollution is a leading risk factor for cardiovascular disease (CVD). However, there is little direct evidence linking exposure to vascular dysfunction. We conducted a cross-sectional study of 100 participants, recruited from the University of Louisville Clinics. Endothelial function was assessed by calculating the reactive hyperemia index (RHI). Oxidative stress was indexed by measuring urinary levels of isoprostanes (n = 91). Inflammatory biomarkers were measured in the plasma (n = 80). Daily average PM_2.5 levels were obtained from regional monitoring stations. Adjusted associations between PM_2.5 levels and measured outcomes were tested using generalized linear models. The average age of participants was 48 years (44% male, 62% white); 52% had a diagnosis of hypertension, and 44% had type-2 diabetes. A 12.4% decrease in RHI was associated with 10 μg/m³ increase in PM_2.5 (95% CI: 21.0, -2.7). The F-2 isoprostane metabolite showed a positive association of 28.4% (95% CI: 2.7, 60.3) per 10 μg/m³ increase in PM_2.5. Positive associations were observed with angiopoietin 1 (17.4%; 95% CI: 2.8, 33.8), vascular endothelial growth factor (10.4%; 95% CI: 0.6, 21.0), placental growth factor (31.7%; 95% CI: 12.2, 54.5), intracellular adhesion molecule-1 (24.6%; 95% CI: 1.6, 52.8), and matrix metalloproteinase-9 (30.3%; 95% CI: 8.0, 57.5) per 10 μg/m³ increase in PM_2.5. Additionally, a 10 μg/m³ increase in PM_2.5 was associated with 15.9% decrease in vascular cell adhesion molecule-1 (95% CI: 28.3, -1.3). These findings suggest that exposure to PM_2.5 is associated with impaired vascular function, which may result from oxidative stress and inflammation, thereby leading to a pro-atherogenic state.

Particulate air pollution and ischemic stroke hospitalization: How the associations vary by constituents in Shanghai, China

BACKGROUND

The identification of constituents of fine particulate matter (PM_2.5) air pollution that had key impacts of ischemic stroke (the predominant subtype of stroke) is important to understand the underlying biological mechanisms and develop air pollution control policies.

OBJECTIVES

To explore the associations between PM_2.5 constituents and hospitalization for ischemic stroke in Shanghai, China.

METHODS

We conducted a time-series study to explore the associations between 27 constituents of PM_2.5 and hospitalization for ischemic stroke in Shanghai, China from 2014 to 2016. The over-dispersed generalized additive models with adjustment for time, day of week, holidays, and weather conditions were used to estimate the associations. We also evaluated the robustness of the effect estimates for each constituent after adjusting for the confounding effects of PM_2.5 total mass and gaseous pollutants and the collinearity (the residual) between this constituent and PM_2.5 total mass. We also compared the associations between seasons.

RESULTS

In total, we identified 4186 ischemic stroke hospitalizations during the study period. The associations of ischemic stroke were consistently significant with elemental carbon and several elemental constituents (Chromium, Iron, Copper, Zinc, Arsenic, Selenium, and Lead) at lag 1 day in single-constituent models, models adjusting for PM_2.5 total mass or gaseous pollutants and models adjusting for collinearity. The associations were much stronger in cool season than in warm season.

CONCLUSIONS

The current study provides suggestive evidence that elemental carbon and some metallic elements may be mainly responsible for the risks of ischemic stroke hospitalization induced by short-term PM_2.5 exposure.

An increase in circulating B cells and B cell activation markers in peripheral blood is associated with cigarette smoking in a male cohort in Bangladesh

In a cohort of approximately 200 Bangladeshi men, equally divided into smokers and non-smokers and equally divided by exposure to high and low levels of drinking water arsenic, we examined ex vivo a series of immune markers and immune function tests in peripheral blood mononuclear cells (PBMC). These immune parameters included PBMC cell surface markers (CSM) for B, T, monocytes, and NK cells, activated T and B cell markers, cytokine production in vitro, and analysis of CD4 subsets (Th1, Th2, Treg, and Th17 cells). We found that the effects of cigarette smoke were quite different than those associated with arsenic or polycyclic aromatic hydrocarbon (PAH)-DNA adducts. Cigarette smoking was associated with a significant increase in the number of PAH-DNA adducts as well as an increase in urinary levels of 1-hydropxypyrene (1-OHP). After correcting for arsenic exposure and PAH-DNA adducts, we found that cigarette smoking was associated with an increase in the percentage of CD19+ B cells, as well as the percentage of activated B cells (CD19+, HLA-DRbright cells) found in PBMC. These findings demonstrate activation of the immune system during chronic exposure to cigarette smoke, which is a known risk factor for autoimmune diseases.

Oxidation Potential Reduction of Carbon Nanomaterials during Atmospheric-Relevant Aging: Role of Surface Coating

Carbon nanomaterials from various sources are the important component of PM_2.5 and have many adverse effects on human health. They are prone to interact with other pollutants and subsequently age, defined here as changes in chemical properties. In this work, we investigated the aging process of various carbon nanoparticle samples such as Special Black 4A, Printex U, single-walled carbon nanotubes, and hexane flame soot by ambient air and studied the evolution of their oxidation potential. We found that coatings of inorganic and organic species dominated the aging process of carbonaceous particles by ambient air. The amounts of disordered carbon and C-H functional groups of aged carbonaceous particles decreased during the aging process; meanwhile, the contents of sulfate and nitrate showed significant increases. In addition, the oxidation potential measured by the dithiothreitol assay remarkably declined as a function of aging time with ambient air evidently because of heterogeneous reactions between SO₂ and NO₂, as well as the coating with organic vapors. This work is important for understanding the oxidation potential changes of carbonaceous particles during atmospheric transport.

Maternal serum metabolome and traffic-related air pollution exposure in pregnancy

BACKGROUND

Maternal exposure to traffic-related air pollution during pregnancy has been shown to increase the risk of adverse birth outcomes and neurodevelopmental disorders. By utilizing high-resolution metabolomics (HRM), we investigated perturbations of the maternal serum metabolome in response to traffic-related air pollution to identify biological mechanisms.

METHODS

We retrieved stored mid-pregnancy serum samples from 160 mothers who lived in the Central Valley of California known for high air particulate levels. We estimated prenatal traffic-related air pollution exposure (carbon monoxide, nitric oxides, and particulate matter <2.5 μm) during first-trimester using the California Line Source Dispersion Model, version 4 (CALINE4) based on residential addresses recorded at birth. We used liquid chromatography-high resolution mass spectrometry to obtain untargeted metabolic profiles and partial least squares discriminant analysis (PLS-DA) to select metabolic features associated with air pollution exposure. Pathway analyses were employed to identify biologic pathways related to air pollution exposure. As potential confounders we included maternal age, maternal race/ethnicity, and maternal education.

RESULTS

In total we extracted 4038 and 4957 metabolic features from maternal serum samples in hydrophilic interaction (HILIC) chromatography (positive ion mode) and C18 (negative ion mode) columns, respectively. After controlling for confounding factors, PLS-DA (Variable Importance in Projection (VIP) ≥2) yielded 181 and 251 metabolic features (HILIC and C18, respectively) that discriminated between the high (n = 98) and low exposed (n = 62). Pathway enrichment analysis for discriminatory features associated with air pollution indicated that in maternal serum oxidative stress and inflammation related pathways were altered, including linoleate, leukotriene, and prostaglandin pathways.

CONCLUSION

The metabolomic features and pathways we found to be associated with air pollution exposure suggest that maternal exposure during pregnancy induces oxidative stress and inflammation pathways previously implicated in pregnancy complications and adverse outcomes.

Short-term exposure to ambient air pollution and circulating biomarkers of endothelial cell activation: The Framingham Heart Study

BACKGROUND

Short-term exposure to air pollution has been associated with cardiovascular events, potentially by promoting endothelial cell activation and inflammation. A few large-scale studies have examined the associations and have had mixed results.

METHODS

We included 3820 non-current smoking participants (mean age 56 years, 54% women) from the Framingham Offspring cohort examinations 7 (1998-2001) and 8 (2005-2008), and Third Generation cohort examination 1 (2002-2005), who lived within 50 km of a central monitoring station. We calculated the 1- to 7-day moving averages of fine particulate matter (PM_2.5), black carbon (BC), sulfate (SO₄^2-), nitrogen oxides (NO_x), and ozone before examination visits. We used linear mixed effect models for P-selectin, monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1, lipoprotein-associated phospholipase A2 activity and mass, and osteoprotegerin that were measured up to twice, and linear regression models for CD40 ligand and interleukin-18 that were measured once, adjusting for demographics, life style and clinical factors, socioeconomic position, time, and meteorology.

RESULTS

We found negative associations of PM_2.5 and BC with P-selectin, of ozone with MCP-1, and of SO₄^2- and NO_x with osteoprotegerin. At the 5-day moving average, a 5 µg/m³ higher PM_2.5 was associated with 1.6% (95% CI: - 2.8, - 0.3) lower levels of P-selectin; a 10 ppb higher ozone was associated with 1.7% (95% CI: - 3.2, - 0.1) lower levels of MCP-1; and a 20 ppb higher NO_x was associated with 2.0% (95% CI: - 3.6, - 0.4) lower levels of osteoprotegerin.

CONCLUSIONS

We did not find evidence of positive associations between short-term air pollution exposure and endothelial cell activation. On the contrary, short-term exposure to higher levels of ambient pollutants were associated with lower levels of P-selectin, MCP-1, and osteoprotegerin in the Framingham Heart Study.

Quenching the fires: Pro-resolving mediators, air pollution, and smoking

Exposure to air pollution and other environmental inhalation hazards, such as occupational exposures to dusts and fumes, aeroallergens, and tobacco smoke, is a significant cause of chronic lung inflammation leading to respiratory disease. It is now recognized that resolution of inflammation is an active process controlled by a novel family of small lipid mediators termed "specialized pro-resolving mediators" or SPMs, derived mainly from dietary omega-3 polyunsaturated fatty acids. Chronic inflammation results from an imbalance between pro-inflammatory and pro-resolution pathways. Research is ongoing to develop SPMs, and the pro-resolution pathway more generally, as a novel therapeutic approach to diseases characterized by chronic inflammation. Here, we will review evidence that the resolution pathway is dysregulated in chronic lung inflammatory diseases, and that SPMs and related molecules have exciting therapeutic potential to reverse or prevent chronic lung inflammation, with a focus on lung inflammation due to inhalation of environmental hazards including urban particulate matter, organic dusts and tobacco smoke.

Cytoprotective Effects of Mangiferin and Z-Ligustilide in PAH-Exposed Human Airway Epithelium in Vitro

According to World Health Organisation (WHO) air pollution increases the risk of cardiovascular disorders, respiratory diseases, including COPD, lung cancer and acute respiratory infections, neuro-degenerative and other diseases. It is also known that various phytochemicals may mitigate such risks. This study tested if phytochemicals mangiferin (MNG) and Z-ligustilide (Z-LG) may protect PAH-exposed human lung bronchial epithelial cells (BEAS-2B). Organic PAH extract was obtained from the urban fine PM with high benzo(a)pyrene content collected in Eastern European mid-sized city during winter heating season. Cell proliferation traits and levels of intracellular oxidative stress were examined. Effect of MNG (0.5 µg/mL) alone or in combination with PAH on bronchial epithelium wound healing was evaluated. Both phytochemicals were also evaluated for their antioxidant properties in acellular system. Treatment with MNG produced strong cytoprotective effect on PAH-exposed cells (p < 0.01) while Z-LG (0.5 µg/mL) exhibited strong negative effect on cell proliferation in untreated and PAH-exposed cells (p < 0.001). MNG, being many times stronger antioxidant than Z-LG in chemical in vitro assays (p < 0.0001), was also able to decrease PAH-induced oxidative stress in the cell cultures (p < 0.05). Consequently MNG ameliorates oxidative stress, speeds up wound healing process and restores proliferation rate in PAH-exposed bronchial epithelium. Such protective effects of MNG in air pollution affected airway epithelium stimulate further research on this promising phytochemical.

Household coal combustion, indoor air pollutants, and circulating immunologic/inflammatory markers in rural China

The study aim was to investigate whether household bituminous ("smoky") coal use and personal exposure to combustion emissions were associated with immunologic/inflammatory marker levels. A cross-sectional study of healthy never-smoking women from rural Xuanwei and Fuyuan, China was conducted, which included 80 smoky coal and 14 anthracite ("smokeless") coal users. Personal exposure to fine particulate matter (PM_2.5) and benzo[a]pyrene (BaP) was assessed using portable devices, while 67 circulating plasma immunologic/inflammatory markers were measured using multiplex bead-based assays. Multivariable linear regression models were employed to estimate associations between smoky coal versus smokeless coal use, indoor air pollutants, and immunologic/inflammatory markers. Six markers were altered among smoky coal users compared to smokeless coal, including significantly decreased interferon-inducible T-cell alpha chemoattractant (CXCL11/I-TAC), and increased serum amyloid P component (SAP). CXCL11/I-TAC was previously found to be reduced in workers exposed to high levels of diesel engine exhaust, which exhibits similar constituents as coal combustion emissions. Further, there was evidence that elevated PM_2.5 and BaP exposure was associated with significantly diminished levels of the serum amyloid A (SAA); however, the false discovery rates (FDRs) were >0.2 after accounting for multiple comparisons. Inflammatory processes may thus mediate the carcinogenic effects attributed to smoky coal emissions.

Acute effects of air pollutants on spontaneous pregnancy loss: a case-crossover study

OBJECTIVE

To investigate the relationship between acute exposure to air pollutants and spontaneous pregnancy loss.

DESIGN

Case-crossover study from 2007 to 2015.

SETTING

An academic emergency department in the Wasatch Front area of Utah.

PATIENT(S)

A total of 1,398 women who experienced spontaneous pregnancy loss events.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Odds of spontaneous pregnancy loss.

RESULT(S)

We found that a 10-ppb increase in 7-day average levels of nitrogen dioxide was associated with a 16% increase in the odds of spontaneous pregnancy loss (odds ratio [OR] = 1.16; 95% confidence interval [CI] 1.01-1.33; P=.04). A 10-μg/m³ increase in 3-day and 7-day averages of fine particulate matter were associated with increased risk of spontaneous pregnancy loss, but the associations did not reach statistical significance (OR_{3-day average} = 1.09; 95% CI 0.99-1.20; P=.05) (OR_{7-day average} = 1.11; 95% CI 0.99-1.24; P=.06). We found no evidence of increased risk for any other metrics of nitrogen dioxide or fine particulate matter or any metric for ozone.

CONCLUSIONS

We found that short-term exposure to elevated levels of air pollutants was associated with higher risk for spontaneous pregnancy loss.

Recent exposure to particle radioactivity and biomarkers of oxidative stress and inflammation: The Framingham Heart Study

BACKGROUND

Decay products of radioactive materials may attach to ambient fine particles and form radioactive aerosol. Internal ionizing radiation source from inhaled radioactive aerosol may contribute to the fine particulate matter (PM2.5)-inflammation pathway. However, few studies in humans have examined the associations.

OBJECTIVES

To examine the associations between particle radioactivity and biomarkers of oxidative stress and inflammation among participants from the Framingham Offspring and Third Generation cohorts.

METHODS

We included 3996 participants who were not current smokers and lived within 50 km from our central air pollution monitoring station. We estimated regional mean gross beta radioactivity from monitors in the northeastern U.S. as a surrogate for ambient radioactive particles, and calculated the 1- to 28-day moving averages. We used linear regression models for fibrinogen, tumor necrosis factor α, interleukin-6, and myeloperoxidase which were measured once, and linear mixed effect models for 8-epi-prostaglandin F2α, C-reactive protein, intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1), P-selectin, and tumor necrosis factor receptor-2 that were measured up to twice, adjusting for demographics, individual- and area-level socioeconomic positions, time, meteorology, and PM2.5. We also examined whether the associations differed by median age, sex, diabetes status, PM2.5 levels, and black carbon levels.

RESULTS

The mean age was 54 years and 54% were women. An interquartile range (3 × 10-3 pCi/m3) higher beta radioactivity level at the 7-day moving average was associated with 5.09% (95% CI: 0.92, 9.43), 2.65% (1.10, 4.22), and 4.71% (95% CI: 3.01, 6.44) higher levels of interleukin-6, MCP-1, and P-selectin, but with 7.01% (95% CI: -11.64, -2.15) and 2.70% (95% CI: -3.97, -1.42) lower levels of 8-epi-prostaglandin F2α and ICAM-1, respectively.

CONCLUSIONS

Regional mean particle radioactivity was positively associated with interleukin-6, MCP-1, and P-selectin, but negatively with ICAM-1 and 8-epi-prostaglandin F2α among our study participants.

Effects of Indoor and Ambient Black Carbon and [Formula: see text] on Pulmonary Function among Individuals with COPD

BACKGROUND

Particulate matter (PM) air pollution has been associated with decreased pulmonary function, but the exposure–response relationship in chronic obstructive pulmonary disease (COPD) patients is uncertain, and most studies have only focused on exposures to ambient pollution.

OBJECTIVES

We aimed to assess associations between pulmonary function and indoor and ambient PM [Formula: see text] ([Formula: see text]) and black carbon (BC).

METHODS

Between November 2012 and December 2014, 125 patients with COPD (mean age, 73.4 y) who were not currently smoking and without known indoor BC sources were recruited. Indoor BC and [Formula: see text] were measured in each home for a week in each season, up to four times a year, followed by in-person spirometry pre- and post-bronchodilator. Ambient exposures were available from a central site monitor. Multivariable adjusted mixed effects regression models were used to assess associations scaled per interquartile range (IQR) of exposure.

RESULTS

There were 367 study visits; the median (IQR) indoor BC and [Formula: see text] were 0.19 (0.22) [Formula: see text] and 6.67 (5.80) [Formula: see text], respectively. Increasing indoor exposures to BC were associated with decreases in pre-bronchodilator forced expiratory volume in 1 s [Formula: see text] and forced vital capacity (FVC), and [Formula: see text]. For example, in multivariable adjusted models, each IQR increase in indoor BC from the weekly integrated filter was associated with a [Formula: see text] [95% confidence interval (CI): [Formula: see text], [Formula: see text]] decrease in pre-bronchodilator [Formula: see text]. Increases in indoor [Formula: see text] were associated with decreases in [Formula: see text] and FVC of smaller magnitude than those for indoor BC; however, the results were less precise. Ambient BC was not associated with pre-bronchodilator pulmonary function, ambient [Formula: see text] was only associated with decreases in FVC and increases in [Formula: see text], and neither indoor nor ambient BC or [Formula: see text] were associated with post-bronchodilator pulmonary function.

CONCLUSIONS

Low-level exposures to indoor BC and [Formula: see text], but not ambient exposures, were consistently associated with decreases in pre-bronchodilator pulmonary function. There was no association between exposures and post-bronchodilator pulmonary function. https://doi.org/10.1289/EHP3668.

Short-term exposure to air pollution: Associations with lung function and inflammatory markers in non-smoking, healthy adults

INTRODUCTION

Air pollution impacts health by increasing mortality and the incidence of acute events in unhealthy individuals. In contrast, the acute effects of pollution in healthy individuals are less obvious. The present study was designed to evaluate the associations between short-term exposure to air pollution on one hand and lung function, and inflammatory markers on the other in middle-aged, non-smoking adults with no respiratory disease, in two urban areas in northern France.

METHODS

A sample of 1506 non-smoking adults (aged from 40 to 65) with no respiratory disease was selected from the participants in the 2011-2013 cross-sectional Enquête Littoral Souffle Air Biologie Environnement (ELISABET) survey in two urban areas in the northern France. We evaluated the associations between (i) mean levels of particulate matter with aerodynamic diameter < 10 μm (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃) exposure on the day and the day before the study examination for each participant, and (ii) spirometry data and levels of inflammatory markers. Coefficients of multiple linear regression models were expressed (except for the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio) as the percentage change [95% confidence interval] per 10 μg increment in each pollutant.

RESULTS

Levels of PM₁₀, NO₂ and O₃ exposure were below or only close to the World Health Organization's recommended limits in our two study areas. An increment in NO₂ levels was significantly associated with a lower FEV1/FVC ratio (-0.38 [-0.64; -0.12]), a lower forced expiratory flow between 25% and 75% of FVC (FEF25-75%) (-1.70 [-3.15; -0.23]), and a lower forced expiratory flow measured at 75% of FVC (FEF75%) (-3.07 [-4.92; -1.18]). An increment in PM₁₀ levels was associated with lower FEF75% (-1.41 [-2.79; -0.01]) and a non-significant elevation in serum levels of high-sensitivity C-reactive protein (+3.48 [-0.25; 7.36], p = 0.07). Lastly, an increment in O₃ levels was associated with a significantly higher blood eosinophil count (+2.41 [0.10; 4.77]) and a non-significant elevation in fractional exhaled nitric oxide (+2.93 [-0.16; 6.13], p = 0.06).

CONCLUSION

A short-term exposure to air pollution was associated with a subclinical decrement in distal lung function and increment in inflammatory markers in healthy inhabitants of two urban areas in France. If these exploratory results are confirmed, this could suggest that even moderate levels of air pollution could have an impact on respiratory health on the general population, and not solely on susceptible individuals.

Traffic-Related Particulate Matter and Cardiometabolic Syndrome: A Review

Traffic-related particulate matter (PM) is a major source of outdoor air pollution worldwide. It has been recently hypothesized to cause cardiometabolic syndrome, including cardiovascular dysfunction, obesity, and diabetes. The environmental and toxicological factors involved in the processes, and the detailed mechanisms remain to be explored. The objective of this study is to assess the current scientific evidence of traffic-related PM-induced cardiometabolic syndrome. We conducted a literature review by searching the keywords of “traffic related air pollution”, “particulate matter”, “human health”, and “metabolic syndrome” from 1980 to 2018. This resulted in 25 independent research studies for the final review. Both epidemiological and toxicological findings reveal consistent correlations between traffic-related PM exposure and the measured cardiometabolic health endpoints. Smaller sizes of PM, particularly ultrafine particles, are shown to be more harmful due to their greater concentrations, reactive compositions, longer lung retention, and bioavailability. The active components in traffic-related PM could be attributed to metals, black carbon, elemental carbon, polyaromatic hydrocarbons, and diesel exhaust particles. Existing evidence points out that the development of cardiometabolic symptoms can occur through chronic systemic inflammation and increased oxidative stress. The elderly (especially for women), children, genetically susceptible individuals, and people with pre-existing conditions are identified as vulnerable groups. To advance the characterization of the potential health risks of traffic-related PM, additional research is needed to investigate the detailed chemical compositions of PM constituents, atmospheric transformations, and the mode of action to induce adverse health effects. Furthermore, we recommend that future studies could explore the roles of genetic and epigenetic factors in influencing cardiometabolic health outcomes by integrating multi-omics approaches (e.g., genomics, epigenomics, and transcriptomics) to provide a comprehensive assessment of biological perturbations caused by traffic-related PM.

Effect of Ambient Fine Particulate Matter Air Pollution and Colder Outdoor Temperatures on High-Density Lipoprotein Function

Fine particulate matter (PM2.5) air pollution and environmental temperatures influence cardiovascular morbidity and mortality. Recent evidence suggests that several air pollutants can promote dyslipidemia; however, the impact of ambient PM2.5 and temperature on high-density lipoprotein (HDL) function remains unclear. We hypothesized that daily exposures to higher levels of ambient PM2.5 and colder outdoor temperatures would impair HDL functionality. Lipoproteins, serum cholesterol efflux capacity (CEC), and HDL oxidation markers were measured twice in 50 healthy adults (age 32.1 ± 9.6 years) living in southeast Michigan and associated with ambient and personal-level exposures using mixed models. Although previous 7-day mean outdoor temperature (4.4 ± 9.8°C) and PM2.5 levels (9.1 ± 1.8 µg/m3) were low, higher ambient PM2.5 exposures (per 10 µg/m3) were associated with significant increases in the total cholesterol-to-HDL-C ratio (rolling average lag days 1 and 2) as well as reductions in CEC by -1.93% (lag day 5, p = 0.022) and -1.62% (lag day 6, p = 0.032). Colder outdoor temperatures (per 10°C) were also associated with decreases in CEC from -0.62 to -0.63% (rolling average lag days 5 and 7, p = 0.027 and 0.028). Previous 24-hour personal-level PM2.5 and temperature exposures did not impact outcomes, nor were any exposures associated with changes in HDL-oxidation metrics. In conclusion, we provide the first evidence that ambient PM2.5 (even at low levels) and outdoor temperatures may influence serum CEC, a critical antiatherosclerotic HDL function.

The protective effects of selenium supplementation on ambient PM2.5-induced cardiovascular injury in rats

Substantial epidemiological and experimental studies have shown that ambient fine particulate matter (PM_2.5) exposure can lead to myocardial damage in human and animal through the mechanism of inflammation and oxidative stress. The purpose of the current study was to investigate whether selenium yeast (SeY) supplementation could prevent cardiovascular injury caused by PM_2.5 in rats. Fifty-six Sprague-Dawley rats were randomly divided into seven groups: saline control group; solvent control group, low-, middle-, and high-dose Se pretreatment groups, PM_2.5 exposure group, and high-dose Se control group. The rats were pretreated with different concentration of dietary SeY for 28 days, then were exposed to PM₂.₅ by intratracheal instillation every other day, a total of three times. The levels of inflammatory markers (tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), soluble intercellular adhesion molecule-1 (sICAM-1), and oxidative responses-related indicators total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured in blood and myocardium of the left ventricle. The results showed that although PM_2.5 caused a decrease of T-AOC, T-AOD, and GSH-Px and increase of MDA and sICM-1, pretreatment with SeY induced a dose-dependent increase in these anti-oxidative indicators and a decrease in oxidative indicators. In addition, the levels of TNF-α and IL-1β in Se pretreatment groups were significantly lower than that in PM_2.5 exposure group. The results indicated that Se supplementation could effectively prevent cardiovascular inflammation and oxidative stress induced by PM_2.5. The results also indicated that the nutritional supplementation might be an effective way to protecting people's health from air pollution.

Ambient air quality and subjective stress level using Community Health Survey data in Korea

OBJECTIVES

Air pollution causes various disease in exposed populations, and can lead to premorbid health effects manifested as both physical and psychological functional impairment. The present study investigated the subjective stress level in daily life in relation to the level of air pollution.

METHODS

Data from the Community Health Survey (2013), comprising 99,162 men, and 121,273 women residing in 253 healthcare administrative districts, were combined with air pollutant concentration modelling data from the Korean Air Quality Forecasting System, and were stratified by subjective stress levels into five strata for multiple logistic regression. Levels of exposure were divided into five quintiles according to the annual concentration of nitrogen dioxide (NO₂), and were analyzed using a single-pollutant model using NO₂ concentration only, and a multi-pollutant model adjusted for the concentration of particulate matter <10 μm in diameter.

RESULTS

Analysis of men and women in various age groups showed the highest odds ratio (OR) for subjective stress level at the highest NO₂ concentration quintile in men and women aged 30–64 years (men: 2.91; 95% confidence interval [CI], 2.12 to 4.01; women: 1.82; 95% CI, 1.32 to 2.51). As the NO₂ concentration quintile increased, the OR increased. Men showed higher ORs than women in all strata.

CONCLUSIONS

In the present study, annual NO₂ concentrations were found to be associated with subjective stress levels. This association was especially clear among socioeconomically active men and women aged 30-64 years.

Indoor black carbon of outdoor origin and oxidative stress biomarkers in patients with chronic obstructive pulmonary disease

OBJECTIVES

We assessed relationships between indoor black carbon (BC) exposure and urinary oxidative stress biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA), in participants with chronic obstructive pulmonary disease (COPD).

METHODS

Eighty-two participants completed in-home air sampling for one week prior to providing urine samples up to four times in a year. Weekly indoor and daily outdoor concentrations were used to estimate indoor daily lags and moving averages. There were no reported in-home BC sources, thus indoor levels closely represented outdoor BC infiltration. Mixed effects regression models with a random intercept for each participant were used to assess relationships between indoor BC and 8-OHdG and MDA, adjusting for age, race, BMI, diabetes, heart disease, season, time of urine collection, urine creatinine, and outdoor humidity and temperature.

RESULTS

There were positive effects of BC on 8-OHdG and MDA, with the greatest effect the day before urine collection (6.9% increase; 95% CI 0.9-13.3%, per interquartile range: 0.22 μg/m³) for 8-OHdG and 1 to 4 days before collection (8.3% increase; 95% CI 0.03-17.3% per IQR) for MDA. Results were similar in models adjusting for PM_2.5 not associated with BC and NO₂ (10.4% increase, 95% CI: 3.5-17.9 for 8-OHdG; 8.1% increase, 95% CI: -1.1-18.1 for MDA). Effects on 8-OHdG were greater in obese participants.

CONCLUSIONS

We found positive associations between BC exposure and 8-OHdG and MDA, in which associations with 8-OHdG were stronger in obese participants. These results suggest that exposure to low levels of traffic-related pollution results in lipid peroxidation and oxidative DNA damage in individuals with COPD.

A review of epidemiological research on stroke and dementia and exposure to air pollution

Background

Outdoor air pollution is now a well-known risk factor for morbidity and mortality, and is increasingly being identified as a major risk factor for stroke.

Methods

A narrative literature review of the effects of short and long-term exposure to air pollution on stroke and dementia risk and cognitive functioning.

Results

Ten papers on stroke and 17 on dementia were selected. Air pollution, and in particular small particulate matter, contributes to about one-third of the global stroke burden and about one-fifth of the global burden of dementia. It particularly affects vulnerable patients with other vascular risk factors or a prior history of stroke in low- and medium-income countries. New pathophysiological mechanisms of the cause-effect associations are suggested.

Conclusion

Air pollution should be considered as a new modifiable cerebrovascular and neurodegenerative risk factor. This massive worldwide public health problem requires environmental health policies able to reduce air pollution and thus the stroke and dementia burden.

Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015

BACKGROUND

Wildfire smoke is known to exacerbate respiratory conditions; however, evidence for cardiovascular and cerebrovascular events has been inconsistent, despite biological plausibility.

METHODS AND RESULTS

A population-based epidemiologic analysis was conducted for daily cardiovascular and cerebrovascular emergency department (ED) visits and wildfire smoke exposure in 2015 among adults in 8 California air basins. A quasi-Poisson regression model was used for zip code-level counts of ED visits, adjusting for heat index, day of week, seasonality, and population. Satellite-imaged smoke plumes were classified as light, medium, or dense based on model-estimated concentrations of fine particulate matter. Relative risk was determined for smoky days for lag days 0 to 4. Rates of ED visits by age- and sex-stratified groups were also examined. Rates of all-cause cardiovascular ED visits were elevated across all lags, with the greatest increase on dense smoke days and among those aged ≥65 years at lag 0 (relative risk 1.15, 95% confidence interval [1.09, 1.22]). All-cause cerebrovascular visits were associated with smoke, especially among those 65 years and older, (1.22 [1.00, 1.49], dense smoke, lag 1). Respiratory conditions were also increased, as anticipated (1.18 [1.08, 1.28], adults >65 years, dense smoke, lag 1). No association was found for the control condition, acute appendicitis. Elevated risks for individual diagnoses included myocardial infarction, ischemic heart disease, heart failure, dysrhythmia, pulmonary embolism, ischemic stroke, and transient ischemic attack.

CONCLUSIONS

Analysis of an extensive wildfire season found smoke exposure to be associated with cardiovascular and cerebrovascular ED visits for all adults, particularly for those over aged 65 years.

Outdoor air pollution, exhaled 8-isoprostane and current asthma in adults: the EGEA study

Associations between outdoor air pollution and asthma in adults are still scarce, and the underlying biological mechanisms are poorly understood. Our aim was to study the associations between 1) long-term exposure to outdoor air pollution and current asthma, 2) exhaled 8-isoprostane (8-iso; a biomarker related to oxidative stress) and current asthma, and 3) outdoor air pollution and exhaled 8-iso.Cross-sectional analyses were conducted in 608 adults (39% with current asthma) from the first follow-up of the French case-control and family study on asthma (EGEA; the Epidemiological study of the Genetic and Environmental factors of Asthma). Data on nitrogen dioxide, nitrogen oxides, particulate matter with a diameter ≤10 and ≤2.5 µm (PM₁₀ and PM_2.5), road traffic, and ozone (O₃) were from ESCAPE (European Study of Cohorts for Air Pollution Effects) and IFEN (French Institute for the Environment) assessments. Models took account of city and familial dependence.The risk of current asthma increased with traffic intensity (adjusted (a)OR 1.09 (95% CI 1.00-1.18) per 5000 vehicles per day), with O₃ exposure (aOR 2.04 (95% CI 1.27-3.29) per 10 µg·m^-3) and with exhaled 8-iso concentration (aOR 1.50 (95% CI 1.06-2.12) per 1 pg·mL^-1). Among participants without asthma, exhaled 8-iso concentration increased with PM_2.5 exposure (adjusted (a)β 0.23 (95% CI 0.005-0.46) per 5 µg·m^-3), and decreased with O₃ and O_3-summer exposures (aβ -0.20 (95% CI -0.39- -0.01) and aβ -0.52 (95% CI -0.77- -0.26) per 10 µg·m^-3, respectively).Our results add new insights into a potential role of oxidative stress in the associations between outdoor air pollution and asthma in adults.

Short-term exposure to traffic-related air pollution and ischemic stroke onset in Barcelona, Spain

OBJECTIVE

To assess the relationship between short-term exposure to outdoor ambient air pollutants (fine particulate matter [PM_2.5] and black carbon [BC]), ischemic stroke (IS) and its different subtypes, and the potential modifying effect of neighborhood greenspace and noise.

METHODS

This time-stratified case-crossover study was based on IS and transient ischemic attacks (TIA) recorded in a hospital-based prospective stroke register (BASICMAR 2005-2014) in Barcelona (Catalonia, Spain). Daily and hourly pollutant concentrations and meteorological data were obtained from monitoring stations in the city. Time-lags (from previous 72h to acute stroke onset) were analyzed. Greenness and noise were determined from the Normalized Difference Vegetation Index (NDVI) and daily average noise level at the street nearest to residential address, respectively.

RESULTS

The 2742 cases with known onset date and time, living in the study area, were analyzed. After adjusting for temperature, no statistically significant association between pollutants exposure and overall stroke risk was found. In subtype analysis, an association was detected between BC exposure at 24-47h (odds ratio, 1.251; 95% confidence interval [CI], 1.001-1.552; P = 0.042) and 48-72h (1.211; 95% CI, 0.988-1.484; P = 0.065) time-lag prior to stroke onset and large-artery atherosclerosis subtype. No clear modifying effect of greenness or noise was observed.

CONCLUSIONS

Overall, no association was found between PM_2.5 and BC exposure and acute IS risk. By stroke subtype, large-artery atherosclerotic stroke could be triggered by daily increases in BC, a diesel fuel-related pollutant in the study area.

Effect of Particulate Matter Air Pollution on Cardiovascular Oxidative Stress Pathways

SIGNIFICANCE

Particulate matter (PM) air pollution is a leading cause of global cardiovascular morbidity and mortality. Understanding the biological action of PM is of particular importance in improvement of public health. Recent Advances: Both fine (PM <2.5 μM) and ultrafine particles (<0.1 μM) are widely believed to mediate their effects through redox regulated pathways. A rather simplistic graded ramp model of redox stress has been replaced by a more sophisticated understanding of the role of oxidative stress in signaling, and the realization that many of the observed effects may involve disruption and/or enhancement of normal endogenous redox signaling and induction of a potent immune-mediated response, through entrainment of multiple reactive oxygen species (ROS).

CRITICAL ISSUES

The molecular events by which pulmonary oxidative stress in response to inhalational exposure to air pollution triggers inflammation, major ROS (e.g., superoxide, hydroxyl radical, nitric oxide, and peroxynitrite) generated in air pollution exposure, types of oxidative tissue damage in target organs, contributions of nonimmune and immune cells in inflammation, and the role of protective proteins (e.g., surfactant, proteins, and antioxidants) are highly complex and may differ depending on models and concomitant disease states.

FUTURE DIRECTIONS

While the role of oxidative stress in the lung has been well demonstrated, the role of oxidative stress in mediating systemic effects especially in inflammation and injury processes needs further work. The role of antioxidant defenses with chronic exposure will also need further exploration. Antioxid. Redox Signal. 28, 797-818.

Temporal variability of global DNA methylation and hydroxymethylation in buccal cells of healthy adults: Association with air pollution

BACKGROUND

Epigenetic changes, such as DNA methylation, are observed in response to environmental exposure and in the development of several chronic diseases. Consequently, DNA methylation alterations might serve as indicators of early effects. In this context, the aim of this study was to assess the temporal variability of global DNA methylation and hydroxymethylation levels in buccal cells from healthy adult volunteers.

METHODS

Global DNA methylation (%5mdC) and hydroxymethylation (%5hmdC) levels in human buccal cells, collected from 26 healthy adults at different time points, were quantified by UPLC-MS/MS. Associations between %5mdC and %5hmdC, respectively, and short-term exposure (1-7days) to air pollutants PM_2.5 and PM₁₀ were tested with mixed-effects models including various covariates.

RESULTS/DISCUSSION

Dynamic short-term changes in DNA methylation and hydroxymethylation levels in buccal cells were observed, which were inversely associated with exposure to PM_2.5 and PM₁₀. An IQR increase in PM_2.5 over a 7-day moving average period was significantly associated with a decrease of -1.47% (-1.74%, -1.20%) and -0.043% (-0.054%, -0.032%) in %5mdC and %5hmdC, respectively. Likewise, for PM₁₀, a decrease of -1.42% (-1.70, -1.13) and -0.040% (-0.051%, -0.028%) was observed.

CONCLUSION

Global DNA methylation and hydroxymethylatation varied over a time period of three weeks. The observed temporal variability was associated with exposure to ambient PM_2.5 and PM₁₀ levels. This should be taken into account when interpreting epigenetic alterations in buccal cells.

Ambient air pollution and the risk of pregnancy loss: a prospective cohort study

OBJECTIVE

To estimate the association of pregnancy loss with common air pollutant exposure. Ambient air pollution exposure has been linked to adverse pregnancy outcomes, but few studies have investigated its relationship with pregnancy loss.

DESIGN

Prospective cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 343 singleton pregnancies in a multisite prospective cohort study with detailed protocols for ovulation and pregnancy testing.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Timing of incident pregnancy loss (from ovulation).

RESULT(S)

The incidence of pregnancy loss was 28% (n = 98). Pollutant levels at women's residences were estimated using modified Community Multiscale Air Quality models and averaged during the past 2 weeks (acute) and the whole pregnancy (chronic). Adjusted Cox proportional hazards models showed that an interquartile range increase in average whole pregnancy ozone (hazard ratio [HR] 1.12, 95% confidence interval [CI] 1.07-1.17) and particulate matter <2.5 μm (HR 1.13, 95% CI 1.03-1.24) concentrations were associated with faster time to pregnancy loss. Sulfate compounds also appeared to increase risk (HR 1.58, 95% CI 1.07-2.34). Last 2 weeks of exposures were not associated with loss.

CONCLUSION(S)

In a prospective cohort of couples trying to conceive, we found evidence that exposure to air pollution throughout pregnancy was associated with loss, but delineating specific periods of heightened vulnerability await larger preconception cohort studies with daily measured air quality.

Ozone exposure effect on systemic prostaglandin F2α in rat plasma and urine may not reveal pulmonary damage through inflammation

The acute ozone induced lung injury model has been widely used to explore injury and repair processes induced by oxidant overload. The current study evaluated acute ozone exposure effects on prostaglandin F_2α (PGF_2α) in male Fischer rat plasma and urine with the hypothesis that ozone may induce an inflammatory response in the body that can be measured by the induction of PGF_2α. That might then lead to the identification of potential marker for acute lung injury through systemic inflammation. The time and dose-dependent effects of ozone exposure on the plasma and urinary levels of a major PGF_2α metabolite15-keto-dihydro-PGF_2α were determined using a radioimmunoassay. No statistically significant differences in the PGF_2α metabolite were found between the control and the experimental groups at either ozone exposure dose (2ppm and 5ppm) or any time point (2h, 7h and 16h) post exposure for plasma and at 7 different post exposure time points (between 2 and 80h) for urine. It is concluded that acute ozone exposure does not cause changes in plasma and urinary PGF_2α, and therefore their measurement in plasma and urine may not be used to reveal pulmonary inflammation and damage by ozone.

Unraveling mechanisms of toxicant-induced oxidative stress in cardiovascular disease

To date, numerous clinical studies examining correlations between oxidative stress biomarkers and cardiovascular diseases (CVD) have repeatedly suggested a role for oxidant injury in the pathogenesis of diseases such as atherosclerosis. Despite this, antioxidant supplementation trials have not demonstrated a reduction in disease progression. Nevertheless, small animal and epidemiological studies have linked exposures to certain toxicants with increased CVD risk involving putative oxidative stress mechanisms. A few prototypical vascular toxicants will be discussed as examples of toxicants that likely act via oxidative stress mechanisms. For discussion, we will classify these toxicants as those that induce direct (e.g., arsenic, nucleoside reverse transcriptase inhibitors) versus indirect (particulate matter, ozone) oxidative stress mechanisms, and those that likely induce CVD through both direct and indirect mechanisms (cigarette smoke). Finally, new findings in oxidative stress research, including the emerging importance of reactive sulfur species, hydrogen peroxide as a presumed endothelium-derived hyperpolarizing factors, etc., will be discussed, as well as the need to determine the role of toxicants in modulating these newly identified pathways. Moreover, given the lack of success in conclusively demonstrating the roles of oxidative stress in CVD risk stratification, research probing the roles of toxicant exposures in propagating CVD pathogenesis may be a novel approach for more conclusively delineating the causal role of oxidative stress in CVD initiation and progression.

Residential Proximity to Major Roadways, Fine Particulate Matter, and Hepatic Steatosis: The Framingham Heart Study

We examined associations between ambient air pollution and hepatic steatosis among 2,513 participants from the Framingham (Massachusetts) Offspring Study and Third Generation Cohort who underwent a computed tomography scan (2002-2005), after excluding men who reported >21 drinks/week and women who reported >14 drinks/week. We calculated each participant's residential-based distance to a major roadway and used a spatiotemporal model to estimate the annual mean concentrations of fine particulate matter. Liver attenuation was measured by computed tomography, and liver-to-phantom ratio (LPR) was calculated. Lower values of LPR represent more liver fat. We estimated differences in continuous LPR using linear regression models and prevalence ratios for presence of hepatic steatosis (LPR ≤ 0.33) using generalized linear models, adjusting for demographics, individual and area-level measures of socioeconomic position, and clinical and lifestyle factors. Participants who lived 58 m (25th percentile) from major roadways had lower LPR (β = -0.003, 95% confidence interval: -0.006, -0.001) and higher prevalence of hepatic steatosis (prevalence ratio = 1.16, 95% confidence interval: 1.05, 1.28) than those who lived 416 m (75th percentile) away. The 2003 annual average fine particulate matter concentration was not associated with liver-fat measurements. Our findings suggest that living closer to major roadways was associated with more liver fat.

Isoprostanes, neuroprostanes and phytoprostanes: An overview of 25years of research in chemistry and biology

Since the beginning of the 1990's diverse types of metabolites originating from polyunsaturated fatty acids, formed under autooxidative conditions were discovered. Known as prostaglandin isomers (or isoprostanoids) originating from arachidonic acid, neuroprostanes from docosahexaenoic acid, and phytoprostanes from α-linolenic acid proved to be prevalent in biology. The syntheses of these compounds by organic chemists and the development of sophisticated mass spectrometry methods has boosted our understanding of the isoprostanoid biology. In recent years, it has become accepted that these molecules not only serve as markers of oxidative damage but also exhibit a wide range of bioactivities. In addition, isoprostanoids have emerged as indicators of oxidative stress in humans and their environment. This review explores in detail the isoprostanoid chemistry and biology that has been achieved in the past three decades.