Changes in traffic exposure and the risk of incident myocardial infarction and all-cause mortality

Comparison of associations between proximity to major roads and all-cause mortality across a spectrum of cardiovascular diseases

Background

Global urbanization is leading to increased exposure to traffic-related air pollution (TRAP), which is associated with adverse health events. While individuals with cardiovascular disease (CVD) are known to have elevated susceptibility to air pollution exposure, no studies have evaluated how mortality risks associated with TRAP exposure differ based on the presence of CVD.

Methods

We used three electronic health record-based cohorts to examine associations between proximity to major roadways and all-cause mortality. The three cohorts were a random sample of the hospital population, individuals with a prior myocardial infarction, and individuals with diagnosed heart failure (HF). We used Cox proportional hazards models to evaluate associations while adjusting for age, race, sex, and census block group socioeconomic status.

Results

Residing <250 m from a major roadway was associated with a hazard ratio (HR) of 1.13 (95% confidence interval = 1.05, 1.23) for individuals with HF, an HR of 1.07 (95% confidence interval = 0.96, 1.20) for those with a prior myocardial infarction, and an HR of 1.03 (95% confidence interval = 0.89, 1.20) for a random sample of hospital patients. This pattern persisted across several sensitivity analyses including alternative definitions of proximity to major roadways and matching the cohorts on demographics.

Conclusion

These results highlight the differences in air quality-related health risks based on underlying CVD. Individuals with HF consistently had the highest environmental health risks. These results may better inform risks related to TRAP exposure in populations with differing underlying CVD.

Long-Term Exposure to Nitrogen Dioxide and Ozone and Mortality: Update of the WHO Air Quality Guidelines Systematic Review and Meta-Analysis

Objectives

We performed a systematic review and meta-analysis on long-term exposure to nitrogen dioxide (NO2) and ozone (O3) with mortality, to expand evidence that informed 2021 the WHO Air Quality Guidelines and guide the Health Risks of Air Pollution in Europe project.

Methods

We included cohorts investigating NO2 and O3 mortality from all-causes, respiratory diseases, chronic obstructive pulmonary disease (COPD), acute lower respiratory infections (ALRI); and NO2 mortality from circulatory, ischemic heart, cerebrovascular diseases and lung cancer. We pooled estimates by random-effects models and investigated heterogeneity. We assessed the certainty of the evidence using the Grading of Recommendations Assessment Development approach and Evaluation (GRADE).

Results

We selected 83 studies for NO2 and 26 for O3 for the meta-analysis. NO2 was associated with all outcomes, except for cerebrovascular mortality. O3 was associated with respiratory mortality following annual exposure. There was high heterogeneity, partly explained by region and pollutant levels. Certainty was high for NO2 with COPD and ALRI, and annual O3 with respiratory mortality.

Conclusion

An increasing body of evidence, with new results from countrywide areas and the Western Pacific, supports certainty, including new outcomes.

Changes in air pollution exposure after residential relocation and body mass index in children and adolescents: A natural experiment study

Air pollution exposure may affect child weight gain, but observational studies provide inconsistent evidence. Residential relocation can be leveraged as a natural experiment by studying changes in health outcomes after a sudden change in exposure within an individual. We aimed to evaluate whether changes in air pollution exposure due to residential relocation are associated with changes in body mass index (BMI) in children and adolescents in a natural experiment study. This population-based study included children and adolescents, between 2 and 17 years, who moved during 2011-2018 and were registered in the primary healthcare in Catalonia, Spain (N = 46,644). Outdoor air pollutants (nitrogen dioxides (NO2), particulate matter <10 μm (PM10) and <2.5 μm (PM2.5)) were estimated at residential census tract level before and after relocation; tertile cut-offs were used to define changes in exposure. Routinely measured weight and height were used to calculate age-sex-specific BMI z-scores. A minimum of 180 days after moving was considered to observe zBMI changes according to changes in exposure using linear fixed effects regression. The majority of participants (60-67% depending on the pollutant) moved to areas with similar levels of air pollution, 15-49% to less polluted, and 14-31% to more polluted areas. Moving to areas with more air pollution was associated with zBMI increases for all air pollutants (β NO2 = 0.10(95%CI 0.09; 0.12), β PM2.5 0.06(0.04; 0.07), β PM10 0.08(0.06; 0.10)). Moving to similar air pollution areas was associated with decreases in zBMI for all pollutants. No associations were found for those moving to less polluted areas. Associations with moving to more polluted areas were stronger in preschool- and primary school-ages. Associations did not differ by area deprivation strata. This large, natural experiment study suggests that increases in outdoor air pollution may be associated with child weight gain, supporting ongoing efforts to lower air pollution levels.

Randomized Cross-Over Study of In-Vehicle Cabin Air Filtration, Air Pollution Exposure, and Acute Changes to Heart Rate Variability, Saliva Cortisol, and Cognitive Function

To determine how traffic-related air pollution (TRAP) exposures affect commuter health, and whether cabin air filtration (CAF) can mitigate exposures, we conducted a cross-over study of 48 adults exposed to TRAP during two commutes with and without CAF. Measurements included particulate air pollutants (PM_2.5, black carbon [BC], ultrafine particles [UFPs]), volatile organic compounds, and nitrogen dioxide. We measured participants' heart rate variability (HRV), saliva cortisol, and cognitive function. On average, CAF reduced concentrations of UFPs by 26,232 (95%CI: 11,734, 40,730) n/cm³, PM_2.5 by 6 (95%CI: 5, 8) μg/m³, and BC by 1348 (95%CI: 1042, 1654) ng/m³, or 28, 30, and 32%, respectively. Each IQR increase in PM_2.5 was associated with a 28% (95%CI: 2, 60) increase in high-frequency power HRV at the end of the commute and a 22% (95%CI: 7, 39) increase 45 min afterward. IQR increases in UFPs were associated with increased saliva cortisol in women during the commute (18% [95%CI: 0, 40]). IQR increases in UFPs were associated with strong switching costs (19% [95%CI: 2, 39]), indicating a reduced capacity for multitasking, and PM_2.5 was associated with increased reaction latency, indicating slower responses (5% [95%CI: 1, 10]). CAF can reduce particulate exposures by almost a third.

Quantifying diurnal changes in NO2 due to COVID-19 stay-at-home orders in New York City

Introduction

Policy responses to the COVID-19 pandemic, such as the NY on Pause stay-at-home order (March 22 - June 8, 2020), substantially reduced traffic and traffic-related air pollution (TRAP) in New York City (NYC). We evaluated the magnitude of TRAP decreases and examined the role of modifying factors such as weekend/weekday, road proximity, location, and time-of-day.

Methods

Hourly nitrogen dioxide (NO₂) concentrations from January 1, 2018 through June 8, 2020 were obtained from the Environmental Protection Agency's Air Quality System for all six hourly monitors in the NYC area. We used an interrupted time series design to determine the impact of NY on Pause on NO₂ concentrations, using a mixed effects model with random intercepts for monitor location, adjusted for meteorology and long-term trends. We evaluated effect modification through stratification.

Results

NO₂ concentrations decreased during NY on Pause by 19% (-3.2 ppb, 95% confidence interval [CI]: -3.5, -3.0), on average, compared to pre-Pause time trends. We found no evidence for modification by weekend/weekday, but greater decreases in NO₂ at non-roadside monitors and weak evidence for modification by location. For time-of-day, we found the largest decreases for 5 am (27%, -4.5 ppb, 95% CI: -5.7, -3.3) through 7 am (24%, -4.0 ppb, 95% CI: -5.2, -2.8), followed by 6 pm and 7 pm (22%, -3.7 ppb, 95% CI: -4.8, -2.6 and 22%, -4.8, -2.5, respectively), while the smallest decreases occurred at 11 pm and 1 am (both: 11%, -1.9 ppb, 95% CI: -3.1, -0.7).

Conclusion

NY on Pause's impact on TRAP varied greatly diurnally. Decreases during early morning and evening time periods are likely due to decreases in traffic. Our results may be useful for planning traffic policies that vary by time of day, such as congestion tolling policies.

Long-Term Exposure to Low-Level NO2 and Mortality among the Elderly Population in the Southeastern United States

BACKGROUND

Mounting evidence has shown that long-term exposure to fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] and ozone (O3) can increase mortality. However, the health effects associated with long-term exposure to nitrogen dioxide (NO2) are less clear, in particular the evidence is scarce for NO2 at low levels that are below the current international guidelines.

METHODS

We constructed a population-based full cohort comprising all Medicare beneficiaries (aged ≥65, N=13,590,387) in the southeastern United States from 2000 to 2016, and we then further defined the below-guideline cohort that included only those who were always exposed to low-level NO2, that is, with annual means below the current World Health Organization guidelines (i.e., ≤21 ppb). We applied previously estimated spatially and temporally resolved NO2 concentrations and assigned annual means to study participants based on their ZIP code of residence. Cox proportional hazards models were used to examine the association between long-term exposure to low-level NO2 and all-cause mortality, adjusting for potential confounders.

RESULTS

About 71.1% of the Medicare beneficiaries in the southeastern United States were always exposed to low-level NO2 over the study period. We observed an association between long-term exposure to low-level NO2 and all-cause mortality, with a hazard ratio (HR)= 1.042 (95% CI: 1.040, 1.045) in single-pollutant models and a HR= 1.047 (95% CI: 1.045, 1.049) in multipollutant models (adjusting for PM2.5 and O3), per 10-ppb increase in annual NO2 concentrations. The penalized spline indicates a linear exposure-response relationship across the entire NO2 exposure range. Medicare enrollees who were White, female, and residing in urban areas were more vulnerable to long-term NO2 exposure.

CONCLUSION

Using a large and representative cohort, we provide epidemiological evidence that long-term exposure to NO2, even below the national and global ambient air quality guidelines, was approximately linearly associated with a higher risk of mortality among older adults, independent of PM2.5 and O3 exposure. Improving air quality by reducing NO2 emissions, therefore, may yield significant health benefits. https://doi.org/10.1289/EHP9044.

Changes in exposure to ambient fine particulate matter after relocating and long term survival in Canada: quasi-experimental study

OBJECTIVE

To investigate the association between changes in long term residential exposure to ambient fine particulate matter (PM_2.5) and premature mortality in Canada.

DESIGN

Population based quasi-experimental study.

SETTING

Canada.

PARTICIPANTS

663 100 respondents to the 1996, 2001, and 2006 Canadian censuses aged 25-89 years who had consistently lived in areas with either high or low PM_2.5 levels over five years preceding census day and moved during the ensuing five years.

INTERVENTIONS

Changes in long term exposure to PM_2.5 arising from residential mobility.

MAIN OUTCOME MEASURES

The primary outcome was deaths from natural causes. Secondary outcomes were deaths from any cardiometabolic cause, any respiratory cause, and any cancer cause. All outcomes were obtained from the national vital statistics database.

RESULTS

Using a propensity score matching technique with numerous personal, socioeconomic, health, and environment related covariates, each participant who moved to a different PM_2.5 area was matched with up to three participants who moved within the same PM_2.5 area. In the matched groups that moved from high to intermediate or low PM_2.5 areas, residential mobility was associated with a decline in annual PM_2.5 exposure from 10.6 μg/m³ to 7.4 and 5.0 μg/m³, respectively. Conversely, in the matched groups that moved from low to intermediate or high PM_2.5 areas, annual PM_2.5 increased from 4.6 μg/m³ to 6.7 and 9.2 μg/m³. Five years after moving, individuals who experienced a reduction in exposure to PM_2.5 from high to intermediate levels showed a 6.8% (95% confidence interval 1.7% to 11.7%) reduction in mortality (2510 deaths in 56 025 v 4925 deaths in 101 960). A greater decline in mortality occurred among those exposed to a larger reduction in PM_2.5. Increased mortality was found with exposure to PM_2.5 from low to high levels, and to a lesser degree from low to intermediate levels. Furthermore, the decreases in PM_2.5 exposure were most strongly associated with reductions in cardiometabolic deaths, whereas the increases in PM_2.5 exposure were mostly related to respiratory deaths. No strong evidence was found for the changes in PM_2.5 exposure with cancer related deaths.

CONCLUSIONS

In Canada, decreases in PM_2.5 were associated with lower mortality, whereas increases in PM_2.5 were associated with higher mortality. These results were observed at PM_2.5 levels considerably lower than many other countries, providing support for continuously improving air quality.

The cardiovascular effects of air pollution: Prevention and reversal by pharmacological agents

Air pollution is associated with staggering levels of cardiovascular morbidity and mortality. Airborne particulate matter (PM), in particular, has been associated with a wide range of detrimental cardiovascular effects, including impaired vascular function, raised blood pressure, alterations in cardiac rhythm, blood clotting disorders, coronary artery disease, and stroke. Considerable headway has been made in elucidating the biological processes underlying these associations, revealing a labyrinth of multiple interacting mechanistic pathways. Several studies have used pharmacological agents to prevent or reverse the cardiovascular effects of PM; an approach that not only has the advantages of elucidating mechanisms, but also potentially revealing therapeutic agents that could benefit individuals that are especially susceptible to the effects of air pollution. This review gathers investigations with pharmacological agents, offering insight into the biology of how PM, and other air pollutants, may cause cardiovascular morbidity.

Residential exposure to traffic-borne pollution as a risk factor for acute cardiocerebrovascular events: a population-based retrospective cohort study in a highly urbanized area

Background

Long-term exposure to traffic-borne noise and air pollution has been variably associated with incidence of acute vascular events, namely acute myocardial infarction, ischaemic stroke and haemorrhagic stroke. This study aims at exploring this association within a highly urbanized city.

Methods

This is a population-based retrospective dynamic cohort study including all residents aged ≥ 35 years in the municipality of Milan over the years 2011–18 (1 087 110 inhabitants). Residential exposure to road traffic noise (day-evening-night levels) and nitrogen dioxide was estimated using a noise predictive model and a land use regression model, respectively. Cox proportional hazards regression analyses were performed to assess the incidence of acute vascular events and specific outcomes in single-exposure and two-exposure models including adjustment for sociodemographic confounders, fine particulate matter and surrounding greenness.

Results

A total of 27 282 subjects (2.5%) had an acute vascular event. Models using nitrogen dioxide produced inconsistent results. The strongest effect was observed for noise, with an optimal cut-off for dichotomization set at 70 dBA (hazard ratio 1.025, 95% confidence interval 1.000–1.050). This association was observed specifically for ischaemic and haemorrhagic stroke. When stratifying by age group and sex, a remarkable effect was found for haemorrhagic stroke in men aged <60 years (hazard ratio 1.439, 95% confidence interval 1.156–1.792).

Conclusions

Living by roads with a day-evening-night noise level above 70 dBA exerts a small but tangible independent effect on the risks of both ischaemic and haemorrhagic stroke. It is urgent to propose mitigation measures against pollution and noise originating from vehicular traffic in order to reduce their impact, especially in the population younger than 60 years.

Long-term exposure to nitrogen dioxide and mortality: A systematic review and meta-analysis

BACKGROUND

Ambient air pollution is among the greatest environmental risks to human health. However, little is known about the health effects of nitrogen dioxide (NO₂), a traffic-related air pollutant. Herein, we aimed to conduct a meta-analysis to investigate the long-term effects of NO₂ on mortality.

METHODS

We conducted a systematic search for studies that were published up to February 2020 and performed a meta-analysis of all available epidemiologic studies evaluating the associations between long-term exposure to NO₂ with all-cause, cardiovascular, and respiratory mortality. Overall pooled effect estimates as well as subgroup-specific pooled estimates (e.g. location, exposure assessment method, exposure metric, study population, age at recruitment, and key confounder adjustment) and 95% confidence intervals were calculated using random-effects models. Risk of bias assessment was accessed by following WHO global air quality guidelines. Publication bias was accessed by visually inspecting funnel plot and Egger's liner regression was used to test of asymmetry.

RESULTS

Our search initially retrieved 1349 unique studies, of which 34 studies met the inclusion criteria. The pooled hazard ratio (HR) for all-cause mortality was 1.06 (95%CI: 1.04-1.08, n = 28 studies, I² = 98.6%) per 10 ppb increase in annual NO₂ concentrations. The pooled HRs for cardiovascular and respiratory mortality per 10 ppb increment were 1.11 (95%CI: 1.07-1.16, n = 20 studies, I² = 99.2%) and 1.05 (95%CI: 1.02-1.08, n = 17 studies, I² = 94.6%), respectively. The sensitivity analysis pooling estimates from multi-pollutant models suggest an independent effect of NO₂ on mortality. Funnel plots indicate that there is no evidence for publication bias in our study.

CONCLUSION

We provide robust epidemiological evidence that long-term exposure to NO₂, a proxy for traffic-sourced air pollutants, is associated with a higher risk of all-cause, cardiovascular, and respiratory mortality that might be independent of other common air pollutants.

Residential proximity to roadways and placental-associated stillbirth: a case-control study

We conducted a retrospective case-control study of 1,097 women in Massachusetts and Rhode Island, USA, to examine the association between stillbirth related to placental abruption or placental insufficiency and maternal exposure to traffic-related air pollution. We utilized distance to nearest roadway proximity metrics as a proxy for traffic-related air pollution exposure. No meaningful increase in the overall odds of placental-associated stillbirths was observed (adjusted OR: 1.1, 95% CI: 0.5-2.8). However, mothers living within 50 m of a roadway had a 60% increased odds of experiencing a stillbirth related to placental abruption compared to mothers living greater than 200 m away. This suggestive finding was imprecise due to the small case number in the highest exposure category (95% CI: 0.6-4.0). Future studies of placental abruption with more precise exposure assessments are warranted.

Manuscript title: Long─term residential exposure to environmental/transportation noise and the incidence of myocardial infarction

BACKGROUND

Cardiovascular effects of environmental noise are a growing concern. However, the evidence remains largely limited to the association between road traffic noise and hypertension and coronary heart diseases.

OBJECTIVES

To investigate the association between long-term residential exposure to environmental/transportation noise and the incidence of myocardial infarction (MI) in the adult population living in Montreal.

METHODS

An open cohort of adults aged 45 years old and over, living on the island of Montreal and free of MI before entering the cohort was created for the years 2000-2014 with the Quebec Integrated Chronic Disease Surveillance System; a systematic surveillance system from the Canadian province of Quebec starting in 1996. Residential noise exposure was calculated in three ways: 1) total ambient noise levels estimated by Land use regression (LUR) models; 2) road traffic noise estimated by a noise propagation model CadnaA and 3) distances to transportation sources (roads, airport, railways). Incident MI was based on diagnostic codes in hospital admission records. Cox models with time-varying exposures (age as the time axis) were used to estimate the associations with various adjustments (material deprivation indicator, calendar year, nitrogen dioxide, stratification for sex). Indirect adjustment based on ancillary data for smoking was performed.

RESULTS

1,065,414 individuals were followed (total of 9,000,443 person-years) and 40,718 (3.8%) developed MI. We found positive associations between total environmental noise, estimated by LUR models and the incidence of MI. Total noise LUR levels ranged from ~44 to ~79 dBA and varied slightly with the metric used. The adjusted hazard ratios (HRs) (also adjusted for smoking) were 1.12 (95% Confidence Intervals [CI]: 1.08-1.15), 1.11 (95%CI: 1.07-1.14) and 1.10 (95%CI: 1.06-1.14) per 10 dBA noise levels increase respectively in Level Accoustic equivalent 24 h (LAeq24 h), Level day-evening-night (Lden) and night level (Lnight). We found a borderline negative association between road noise levels estimated with CadnaA and MI (HR: 0.99 per 10 dBA; 95%CI: 0.98-1.00). Distances to major roads and highways were not associated with MI while the proximity to railways was positively associated with MI (HR for ≤100 vs > 1000 m: 1.07; 95%CI: 1.01-1.14). A negative association was found with the proximity to the airport noise exposure forecast (NEF25); HR (<1 vs >1000 m) = 0.88 (95%CI: 0.81-0.96).

CONCLUSIONS

These associations suggest that exposure to total environmental noise at current urban levels may be related to the incidence of MI. Additional studies with more accurate road noise estimates are needed to explain the counterintuitive associations with road noise and specific transportation sources.

Long-term exposure to NO2 and O3 and all-cause and respiratory mortality: A systematic review and meta-analysis

BACKGROUND

WHO has published several volumes of Global Air Quality Guidelines to provide guidance on the health risks associated with exposure to outdoor air pollution. As new scientific evidence is generated, air quality guidelines need to be periodically revised and, where necessary, updated.

OBJECTIVES

The aims of the study were 1) to summarise the available evidence on the effect of long-term exposure to ozone (O3) and nitrogen dioxide (NO2) on mortality; 2) and to assess concentration response functions (CRF), their shape and the minimum level of exposures measured in studies to support WHO's update of the global air quality guidelines.

DATA SOURCES

We conducted a systematic literature search of the Medline, Embase and Web of Science databases following a protocol proposed by WHO and applied Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines for reporting our results.

STUDY ELIGIBILITY CRITERIA

Cohort studies in human populations (including sub-groups at risk) exposed to long-term concentrations of NO2 and O3. Outcomes assessed were all-cause, respiratory, Chronic Obstructive Pulmonary Disease (COPD) and Acute Lower Respiratory Infection (ALRI) mortality.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies included in the meta-analyses were assessed using a new Risk of Bias instrument developed by a group of experts convened by WHO. Study results are presented in forest plots and quantitative meta-analyses were conducted using random effects models. The certainty of evidence was assessed using a newly developed adaptation of GRADE.

RESULTS

The review identified 2068 studies of which 95 were subject to full-text review with 45 meeting the inclusion criteria. An update in September 2018 identified 159 studies with 1 meeting the inclusion criteria. Of the 46 included studies, 41 reported results for NO2 and 20 for O3. The majority of studies were from the USA and Europe with the remainder from Canada, China and Japan. Forty-two studies reported results for all-cause mortality and 22 for respiratory mortality. Associations for NO2 and mortality were positive; random-effects summary relative risks (RR) were 1.02 (95% CI: 1.01, 1.04), 1.03 (1.00, 1.05), 1.03 (1.01, 1.04) and 1.06 (1.02, 1.10) per 10 μg/m3 for all-cause (24 cohorts), respiratory (15 cohorts), COPD (9 cohorts) and ALRI (5 cohorts) mortality respectively. The review identified high levels of heterogeneity for all causes of death except COPD. A small number of studies investigated the shape of the concentration-response relationship and generally found little evidence to reject the assumption of linearity across the concentration range. Studies of O3 using annual metrics showed the associations with all-cause and respiratory mortality were 0.97 (0.93, 1.02) and 0.99 (0.89, 1.11) per 10 μg/m3 respectively. For studies using peak O3 metrics, the association with all-cause mortality was 1.01 (1.00, 1.02) and for respiratory mortality 1.02 (0.99, 1.05), each per 10 μg/m3. The review identified high levels of heterogeneity. Few studies investigated the shape of the concentration-response relationship. Certainty in the associations (adapted GRADE) with mortality was rated low to moderate for each exposure-outcome pair, except for NO2 and COPD mortality which was rated high.

LIMITATIONS

The substantial heterogeneity for most outcomes in the review requires explanation. The evidence base is limited in terms of the geographical spread of the study populations and, for some outcomes, the small number of independent cohorts for meta-analysis precludes meaningful meta-regression to explore causes of heterogeneity. Relatively few studies assessed specifically the shape of the CRF or multi-pollutant models.

CONCLUSIONS

The short-comings in the existing literature base makes determining the precise nature (magnitude and linearity) of the associations challenging. Certainty of evidence assessments were moderate or low for both NO2 and O3 for all causes of mortality except for NO2 and COPD mortality where the certainty of the evidence was judged as high.

Impact of residential mobility on estimated environmental exposures in a prospective cohort of older women

Longitudinal studies of environmental hazards often rely on exposure estimated at the participant's enrollment residence. This could lead to exposure misclassification if participants move over time.

Methods

We evaluated residential mobility in the Iowa Women's Health Study (age 55-69 years) over 19 years of follow-up (1986-2004). We assessed several environmental exposures of varying spatial scales at enrollment and follow-up addresses. Exposures included average nitrate concentrations in public water supplies, percent of agricultural land (row crops and pasture/hay) within 750 m, and the presence of concentrated animal feeding operations within 5 km. In comparison to gold standard duration-based exposures averaged across all residences, we evaluated the sensitivity and specificity of exposure metrics and attenuation bias for a hypothetical nested case-control study of cancer, which assumed participants did not move from their enrollment residence.

Results

Among 41,650 participants, 32% moved at least once during follow-up. Mobility was predicted by working outside the home, being a former/current smoker, having a higher education level, using a public drinking water supply, and town size of previous residence. Compared with duration-based exposures, the sensitivity and specificity of exposures at enrollment ranged from 94% to 99% and 97% to 99%, respectively. A hypothetical true odds ratio of 2.0 was attenuated 8% for nitrate, 9%-10% for agricultural land, and 6% for concentrated animal feeding operation exposures.

Conclusions

Overall, we found low rates of mobility and mobility-related exposure misclassification in the Iowa Women's Health Study. Misclassification and attenuation of hypothetical risk estimates differed by spatial variability and exposure prevalence.

Estimation in the Cox survival regression model with covariate measurement error and a changepoint

The Cox regression model is a popular model for analyzing the relationship between a covariate vector and a survival endpoint. The standard Cox model assumes a constant covariate effect across the entire covariate domain. However, in many epidemiological and other applications, the covariate of main interest is subject to a threshold effect: a change in the slope at a certain point within the covariate domain. Often, the covariate of interest is subject to some degree of measurement error. In this paper, we study measurement error correction in the case where the threshold is known. Several bias correction methods are examined: two versions of regression calibration (RC1 and RC2, the latter of which is new), two methods based on the induced relative risk under a rare event assumption (RR1 and RR2, the latter of which is new), a maximum pseudo-partial likelihood estimator (MPPLE), and simulation-extrapolation (SIMEX). We develop the theory, present simulations comparing the methods, and illustrate their use on data concerning the relationship between chronic air pollution exposure to particulate matter PM₁₀ and fatal myocardial infarction (Nurses Health Study (NHS)), and on data concerning the effect of a subject's long-term underlying systolic blood pressure level on the risk of cardiovascular disease death (Framingham Heart Study (FHS)). The simulations indicate that the best methods are RR2 and MPPLE.

Sustainable Policy Evaluation of Vehicle Exhaust Control—Empirical Data from China’s Air Pollution Control

With the increase of car ownership, mobile pollution has become an important source of air pollution, which makes it more difficult for China to control air pollution. In order to control mobile pollution from automobile exhaust, China has taken a series of comprehensive measures. The paper studies the emission reduction effect from the perspective of flow pollution and stock pollution. First of all, the paper uses the actual emission data of motor vehicles to study the emission reduction effect by gasoline and diesel vehicles. The results show that: (1) Fuel price, fuel tax (except diesel), and emission and gasoline standards have an emission reduction effect on gasoline vehicle exhaust control, while the restriction has no effect. (2) In gasoline cars, the emission reduction effect in the Middle East is more significant than in the West, and the effect in the West is better than that in the Middle East. (3) As for diesel vehicles, the effect of policy in the West is superior to the East. Further, the east is better than in the middle. Secondly, based on the actual emission data of Chinese motor vehicles, the paper simulates the change value of stock pollution from automobile exhaust under different policies, and concludes that the economic effect of policy depends on the ecological absorption rate and discount rate. When the net discount value NPV is positive, the government should do its best to interfere with the emission of automobile exhaust. When the net discount value NPV is negative, the government doesn’t have to interfere with the emission of automobile exhaust.

The influence of roadside trees on the diffusion of road traffic pollutants and their magnetic characteristics in a typical semi-arid urban area of Northwest China

Leaf samples of Juniperus formosana were collected from an open road environment, in order to establish how particulate matter (PM) generated by vehicles was dispersed in both horizontal and vertical directions. Sampling was conducted at sites with trees of varying height and configuration adjacent to a major road in Lanzhou, Gansu Province, Northwest China. The concentration of remanence-bearing ferrimagnets in the leaf samples was estimated from measurements of Saturation Isothermal Remanent Magnetization (SIRM), while the weight of particles deposited on the leaves and their elemental composition were determined at different heights and in different directions relative to the road. The PM on the surface of needles was predominantly influenced by traffic emissions and by dust resuspension. Rows of roadside trees, as opposed to solitary trees, were more effective at intercepting PM and thus in filtering road traffic pollution. The results indicate that Juniperus formosana needles may be an effective bio-sensor for monitoring variations in the spatial diffusion of road pollutants.

Synthesis of Harvard Environmental Protection Agency (EPA) Center studies on traffic-related particulate pollution and cardiovascular outcomes in the Greater Boston Area

The association between particulate pollution and cardiovascular morbidity and mortality is well established. While the cardiovascular effects of nationally regulated criteria pollutants (e.g., fine particulate matter [PM_2.5] and nitrogen dioxide) have been well documented, there are fewer studies on particulate pollutants that are more specific for traffic, such as black carbon (BC) and particle number (PN). In this paper, we synthesized studies conducted in the Greater Boston Area on cardiovascular health effects of traffic exposure, specifically defined by BC or PN exposure or proximity to major roadways. Large cohort studies demonstrate that exposure to traffic-related particles adversely affect cardiac autonomic function, increase systemic cytokine-mediated inflammation and pro-thrombotic activity, and elevate the risk of hypertension and ischemic stroke. Key patterns emerged when directly comparing studies with overlapping exposure metrics and population cohorts. Most notably, cardiovascular risk estimates of PN and BC exposures were larger in magnitude or more often statistically significant compared to those of PM_2.5 exposures. Across multiple exposure metrics (e.g., short-term vs. long-term; observed vs. modeled) and different population cohorts (e.g., elderly, individuals with co-morbidities, young healthy individuals), there is compelling evidence that BC and PN represent traffic-related particles that are especially harmful to cardiovascular health. Further research is needed to validate these findings in other geographic locations, characterize exposure errors associated with using monitored and modeled traffic pollutant levels, and elucidate pathophysiological mechanisms underlying the cardiovascular effects of traffic-related particulate pollutants. Implications: Traffic emissions are an important source of particles harmful to cardiovascular health. Traffic-related particles, specifically BC and PN, adversely affect cardiac autonomic function, increase systemic inflammation and thrombotic activity, elevate BP, and increase the risk of ischemic stroke. There is evidence that BC and PN are associated with greater cardiovascular risk compared to PM_2.5. Further research is needed to elucidate other health effects of traffic-related particles and assess the feasibility of regulating BC and PN or their regional and local sources.

PM2.5 promotes plaque vulnerability at different stages of atherosclerosis and the formation of foam cells via TLR4/MyD88/NFκB pathway

Clinical evidence has shown an elevated myocardial infarction (MI) risk after PM2.5 (particulate matter < 2.5 μm) exposure. Incident MI may result from rupture of vulnerable plaques. To test whether PM2.5 could promote plaque vulnerability, we exposed PM2.5 to apoe^-/- mice by intranasal instillation. We detected the lipid, collagen, macrophage and smooth muscle cells (SMCs) content, and fibrous cap thickness to evaluate the plaque vulnerability. Plaques in HFD-fed mice with PM2.5 treatment for 24 weeks had increased lipid content and macrophage recruitment, and reduced collagen content, fibrous cap thickness and SMCs infiltration. Besides, 4-week exposure to PM2.5 could reduce the fibrous cap thickness, collagen content, but increase the macrophage infiltration and SMCs loss in a rapid atherosclerosis model. In existing plaques, PM2.5 could also decrease the fibrous cap thickness, collagen content. In RAW264.7, PM2.5 could promote the transformation of macrophage into foam cells. The expression of TLR4/MyD88/NFκB and CD36 were upregulated by PM2.5 treatment. Besides, the expression of CD36 promoted by PM2.5 was downregulated by the TLR4 inhibitor or MyD88/NFκB SiRNA. In conclusion, our data indicated that short- and long-term PM2.5 exposure increased plaque vulnerability. The underlying mechanism might be the PM2.5-enhanced formation of foam cells via TLR4/MyD88/NFκB pathway.

Inflammatory health effects of indoor and outdoor particulate matter

Inflammation is a common and essential event in the pathogenesis of diverse diseases. Decades of research has converged on an understanding that all combustion-derived particulate matter (PM) is inflammatory to some extent in the lungs and also systemically, substantially explaining a significant portion of the massive cardiopulmonary disease burden associated with these exposures. In general, this means that efforts to do the following can all be beneficial: reduce particulates at the source, decrease the inflammatory potential of PM output, and, where PM inhalation is unavoidable, administer anti-inflammatory treatment. A range of research, including basic illumination of inflammatory pathways, assessment of disease burden in large cohorts, tailored treatment trials, and epidemiologic, animal, and in vitro studies, is highlighted in this review. However, meaningful translation of this research to decrease the burden of disease and deliver a clear and cohesive message to guide daily clinical practice remains rudimentary. Ongoing efforts to better understand substantial differences in the concentration and type of PM to which the global community is exposed and then distill how that influences inflammation promises to have real-world benefit. This review addresses this complex topic in 3 sections, including ambient PM (typically associated with ground-level transportation), wildfire-induced PM, and PM from indoor biomass burning. Recognizing the overlap between these domains, we also describe differences and suggest future directions to better inform clinical practice and public health.

Magnetic characteristics of Juniperus formosana needles along an urban street in Lanzhou, Northwest China: the variation of different season and orientation

The magnetic properties of particulate matter (PM) deposited on the needles of Juniperus formosana along an urban street in Lanzhou city were measured to evaluate the variations of PM concentration in different seasons by varying distance from the road. The magnetism of PM deposited in this context was significantly higher in winter than in summer, which may reflect changes of atmospheric particle concentrations. Needle samples which were collected from the road-facing side exhibiting significantly stronger magnetism compared with those which were collected from the opposite side of the road, indicating the distance from pollution source to the needles as a factor controls the amount of PM. The results of this study show that the needles of Juniperus formosana are effective traps for PM and can therefore be used to monitor pollution fluxes in different seasons in an important urban context in NW China.

Associations of Long-Term Exposure to Ultrafine Particles and Nitrogen Dioxide With Increased Incidence of Congestive Heart Failure and Acute Myocardial Infarction

Although long-term exposure to traffic-related air pollutants such as nitrogen dioxide has been linked to cardiovascular disease (CVD) mortality, little is known about the association between ultrafine particles (UFPs), defined as particles less than or equal to 0.1 μm in diameter, and incidence of major CVD events. We conducted a population-based cohort study to assess the associations of chronic exposure to UFPs and nitrogen dioxide with incident congestive heart failure (CHF) and acute myocardial infarction. Our study population comprised all long-term Canadian residents aged 30-100 years who lived in Toronto, Ontario, Canada, during the years 1996-2012. We estimated annual concentrations of UFPs and nitrogen dioxide by means of land-use regression models and assigned these estimates to participants' postal-code addresses in each year during the follow-up period. We estimated hazard ratios for the associations of UFPs and nitrogen dioxide with incident CVD using random-effects Cox proportional hazards models. We controlled for smoking and obesity using an indirect adjustment method. Our cohorts comprised approximately 1.1 million individuals at baseline. In single-pollutant models, each interquartile-range increase in UFP exposure was associated with increased incidence of CHF (hazard ratio for an interquartile-range increase (HRIQR) = 1.03, 95% confidence interval (CI): 1.02, 1.05) and acute myocardial infarction (HRIQR = 1.05, 95% CI: 1.02, 1.07). Adjustment for fine particles and nitrogen dioxide did not materially change these estimated associations. Exposure to nitrogen dioxide was also independently associated with higher CHF incidence (HRIQR = 1.04, 95% CI: 1.03, 1.06).

High-resolution mapping of traffic related air pollution with Google street view cars and incidence of cardiovascular events within neighborhoods in Oakland, CA

BACKGROUND

Some studies have linked long-term exposure to traffic related air pollutants (TRAP) with adverse cardiovascular health outcomes; however, previous studies have not linked highly variable concentrations of TRAP measured at street-level within neighborhoods to cardiovascular health outcomes.

METHODS

Long-term pollutant concentrations for nitrogen dioxide [NO₂], nitric oxide [NO], and black carbon [BC] were obtained by street-level mobile monitoring on 30 m road segments and linked to residential addresses of 41,869 adults living in Oakland during 2010 to 2015. We fit Cox proportional hazard models to estimate the relationship between air pollution exposures and time to first cardiovascular event. Secondary analyses examined effect modification by diabetes and age.

RESULTS

Long-term pollutant concentrations [mean, (standard deviation; SD)] for NO₂, NO and BC were 9.9 ppb (SD 3.8), 4.9 ppb (SD 3.8), and 0.36 μg/m3 (0.17) respectively. A one SD increase in NO₂, NO and BC, was associated with a change in risk of a cardiovascular event of 3% (95% confidence interval [CI] -6% to 12%), 3% (95% CI -5% to 12%), and - 1% (95% CI -8% to 7%), respectively. Among the elderly (≥65 yrs), we found an increased risk of a cardiovascular event of 12% for NO₂ (95% CI: 2%, 24%), 12% for NO (95% CI: 3%, 22%), and 7% for BC (95% CI: -3%, 17%) per one SD increase. We found no effect modification by diabetes.

CONCLUSIONS

Street-level differences in long-term exposure to TRAP were associated with higher risk of cardiovascular events among the elderly, indicating that within-neighborhood differences in TRAP are important to cardiovascular health. Associations among the general population were consistent with results found in previous studies, though not statistically significant.

Residential green space and birth outcomes in a coastal setting

BACKGROUND

Residential green space may improve birth outcomes, with prior studies reporting higher birthweight among infants of women living in greener areas. However, results from studies evaluating associations between green space and preterm birth have been mixed. Further, the potential influence of residential proximity to water, or 'blue space', on health has not previously been evaluated.

OBJECTIVES

To evaluate associations between green and blue space and birth outcomes in a coastal area of the northeastern United States.

METHODS

Using residential surrounding greenness (measured by Normalized Difference Vegetation Index [NDVI]) and proximity to recreational facilities, coastline, and freshwater as measures of green and blue space, we examined associations with preterm birth (PTB), term birthweight, and term small for gestational age (SGA) among 61,640 births in Rhode Island. We evaluated incremental adjustment for socioeconomic and environmental metrics.

RESULTS

In models adjusted for individual - and neighborhood-level markers of socioeconomic status (SES), an interquartile range (IQR) increase in NDVI was associated with a 12% higher (95% CI: 4, 20%) odds of PTB and, conversely, living within 500 m of a recreational facility was associated with a 7% lower (95% CI: 1, 13%) odds of PTB. These associations were eliminated after further adjustment for town of residence. NDVI was associated with higher birthweight (7.4 g, 95% CI: 0.4-14.4 g) and lower odds of SGA (OR = 0.92, 95% CI: 0.87-0.98) when adjusted for individual-level markers of SES, but not when further adjusted for neighborhood SES or town. Living within 500 m of a freshwater body was associated with a higher birthweight of 10.1 g (95% CI: 2.0, 18.2) in fully adjusted models.

CONCLUSIONS

Findings from this study do not support the hypothesis that residential green space is associated with reduced risk of preterm birth or higher birthweight after adjustment for individual and contextual socioeconomic factors, but variation in results with incremental adjustment raises questions about the optimal degree of control for confounding by markers of SES. We found that living near a freshwater body was associated with higher birthweight. This result is novel and bears further investigation in other settings and populations.

Environmental Exposures and Cardiovascular Disease: A Challenge for Health and Development in Low- and Middle-Income Countries

Environmental exposures in low- and middle-income countries lie at the intersection of increased economic development and the rising public health burden of cardiovascular disease. Increasing evidence suggests an association of exposure to ambient air pollution, household air pollution from biomass fuel, lead, arsenic, and cadmium with multiple cardiovascular disease outcomes, including hypertension, coronary heart disease, stroke, and cardiovascular mortality. Although populations in low- and middle-income countries are disproportionately exposed to environmental pollution, evidence linking these exposures to cardiovascular disease is derived from populations in high-income countries. More research is needed to further characterize the extent of environmental exposures.

Residential road traffic noise exposure and survival after breast cancer - A cohort study

BACKGROUND

It is generally acknowledged that patients with already existing clinical conditions are especially vulnerable to the effects of traffic noise exposure. The aim of the present study was to investigate the association between residential road traffic noise and breast cancer survival.

METHODS

Road traffic noise was calculated for all residential addresses from 1987 to February 2012 for incident breast cancer cases (n=1,759) in a cohort of 57,053 Danes. We used Cox Proportional Hazard Models to investigate the association between residential road traffic noise at different time-windows, and overall and breast cancer-specific mortality. Furthermore, we investigated interaction with prognostic and socioeconomic factors. Mortality Rate Ratios (MRR) were calculated in both unadjusted models, and adjusted for residential railway noise, lifestyle factors and socioeconomic variables.

RESULTS

During a median of 7.3 years of follow-up, 402 patients died; 274 from breast cancer. We found no association between time-weighted averages of residential road traffic noise 1-, 3- or 5-years before death, or over the entire follow-up period, and overall or breast cancer-specific mortality. A 10dB higher road traffic noise from diagnosis until censoring was associated with an adjusted MRR of 0.94 (0.81-1.08) for all-cause mortality. The association was modified by lymph node involvement, with a MRR of 1.20 (0.97-1.48) for those with tumor-positive lymph nodes and 0.76 (0.59-0.98) for those without.

CONCLUSION

The present study suggests no association between residential road traffic noise and concurrent mortality. As it is the first study of its kind, with relatively limited power, further studies are warranted.

Associations of Source-Specific Fine Particulate Matter With Emergency Department Visits in California

While many studies have investigated the health effects associated with acute exposure to fine particulate matter (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5)), very few have considered the risks of specific sources of PM2.5 We used city-specific source apportionment in 8 major metropolitan areas in California from 2005-2009 to examine the associations of source-specific PM2.5 exposures from vehicular emissions, biomass burning, soil, and secondary nitrate and sulfate sources with emergency department visits (EDVs) for cardiovascular and respiratory diseases, including 7 subclasses. Using a case-crossover analysis, we observed associations of vehicular emissions with all cardiovascular EDVs (excess risk = 1.6%, 95% confidence interval: 0.9, 2.4 for an interquartile-range increment of 2.8 µg/m(3)) and with several subclasses of disease. In addition, vehicular emissions, biomass burning, and soil sources were associated with all respiratory EDVs and with EDVs for asthma. The soil source, which includes resuspended road dust, generated the highest risk estimate for asthma (excess risk = 4.5%, 95% confidence interval: 1.1, 8.0). Overall, our results provide additional evidence of the public health consequences of exposure to specific sources of PM2.5 and indicate that some sources of PM2.5 may pose higher risks than the overall PM2.5 mass.

Air pollution and ST-elevation myocardial infarction: A case-crossover study of the Belgian STEMI registry 2009-2013

BACKGROUND

Previous studies have shown that air pollution particulate matter (PM) is associated with an increased risk for myocardial infarction. The effects of air pollution on the risk of ST-elevation myocardial infarction (STEMI), in particular the role of gaseous air pollutants such as NO₂ and O₃ and the susceptibility of specific populations, are still under debate.

METHODS

All patients entered in the Belgian prospective STEMI registry between 2009 and 2013 were included. Based on a validated spatial interpolation model from the Belgian Environment Agency, a national index was used to address the background level of air pollution exposure of Belgian population. A time-stratified and temperature-matched case-crossover analysis of the risk of STEMI was performed.

RESULTS

A total of 11,428 STEMI patients were included in the study. Each 10μg/m³ increase in PM10, PM2.5 and NO₂ was associated with an increased odds ratio (ORs) of STEMI of 1.026 (CI _95%: 1.005-1.048), 1.028 (CI _95%: 1.003-1.054) and 1.051 (CI _95%: 1.018-1.084), respectively. No effect of O₃ was found. STEMI was associated with PM10 exposure in patients ≥75y.o. (OR: 1.046, CI _95%: 1.002-1.092) and with NO₂ in patients ≤54y.o. (OR: 1.071, CI _95%: 1.010-1.136). No effect of air pollution on cardiac arrest or in-hospital STEMI mortality was found.

CONCLUSION

PM2.5 and NO₂ exposures incrementally increase the risk of STEMI. The risk related to PM appears to be greater in the elderly, while younger patients appear to be more susceptible to NO₂ exposure.

Maternal residential proximity to major roadways, birth weight, and placental DNA methylation

BACKGROUND

Exposure to traffic pollution during fetal development has been associated with reduced fetal growth, and there is evidence to suggest that epigenetic mechanisms in the placenta in the form of variant DNA methylation may be a potential mechanism underlying this effect.

OBJECTIVES

To examine the association between residential proximity to nearest major roadway, as a marker of traffic-related pollution, fetal growth and placental DNA methylation.

METHODS

We obtained residential addresses, placenta samples, and demographic data from 471 women following delivery of term infants. Using generalized linear models we evaluated the association between living close to a major roadway (defined as living ≤150m from a primary highway or primary road or ≤50m from a secondary road) and fetal growth and DNA methylation of repetitive elements (LINE-1 and AluYb8). We evaluated epigenome-wide methylation in a subset of 215 women to further investigate specific variation in DNA methylation associated with proximity to major roadways.

RESULTS

Living close to a major roadway was associated with a 175.9g (95% CI: -319.4, -32.5; p=0.016) lower birth weight, 1.8 (95% CI: 0.9, 3.8; p=0.09) times the odds of being small for gestational age, and 0.82 percentage points (95% CI: -1.57, -0.07; p=0.03) lower mean placental LINE-1 methylation levels in fully adjusted models. In epigenome-wide analyses, 7 CpG sites were significantly associated with residential proximity to major roadways. Additional adjustment for placental methylation did not attenuate the association between roadway proximity and birth weight.

CONCLUSIONS

Living close to major roadways was associated with both lower fetal growth and significant placental epigenetic changes. However, the observed epigenetic changes appear insufficient to explain the observed association between roadway proximity and fetal growth.

Air pollution exposure, cause-specific deaths and hospitalizations in a highly polluted Italian region

BACKGROUND

The Lombardy region in northern Italy ranks among the most air polluted areas of Europe. Previous studies showed air pollution short-term effects on all-cause mortality. We examine here the effects of particulate matter with aerodynamic diameter ≤10µm (PM10) and nitrogen dioxide (NO2) exposure on deaths and hospitalizations from specific causes, including cardiac, cerebrovascular and respiratory diseases.

METHODS

We considered air pollution, mortality and hospitalization data for a non-opportunistic sample of 18 highly polluted and most densely populated areas of the region in the years 2003-2006. We obtained area-specific effect estimates for PM10 and NO2 from a Poisson regression model on the daily number of total deaths or cause-specific hospitalizations and then combined them in a Bayesian random-effects meta-analysis. For cause-specific mortality, we applied a case-crossover analysis. Age- and season-specific analyses were also performed. Effect estimates were expressed as percent variation in mortality or hospitalizations associated with a 10µg/m(3) increase in PM10 or NO2 concentration.

RESULTS

Natural mortality was positively associated with both pollutants (0.30%, 90% Credibility Interval [CrI]: -0.31; 0.78 for PM10; 0.70%, 90%CrI: 0.10; 1.27 for NO2). Cardiovascular deaths showed a higher percent variation in association with NO2 (1.12%, 90% Confidence Interval [CI]: 0.14; 2.11), while the percent variation for respiratory mortality was highest in association with PM10 (1.64%, 90%CI: 0.35; 2.93). The effect of both pollutants was more evident in the summer season. Air pollution was also associated to hospitalizations, the highest variations being 0.77% (90%CrI: 0.22; 1.43) for PM10 and respiratory diseases, and 1.70% (90%CrI: 0.39; 2.84) for NO2 and cerebrovascular diseases. The effect of PM10 on respiratory hospital admissions appeared to increase with age. For both pollutants, effects on cerebrovascular hospitalizations were more evident in subjects aged less than 75 years.

CONCLUSIONS

Our study provided a sound characterization of air pollution exposure and its potential effects on human health in the most polluted, and also most populated and productive, Italian region, further documenting the need for effective public health policies.

Long term effects of traffic noise on mortality in the city of Barcelona, 2004-2007

Numerous studies showing statistically significant associations between environmental noise and adverse health effects already exist for short-term (over one day at most) and long-term (over a year or more) noise exposure, both for morbidity and (albeit to a lesser extent) mortality. Recently, several studies have shown this association to be independent from confounders, mainly those of air pollutants. However, what has not been addressed is the problem of misalignment (i.e. the exposure data locations and health outcomes have different spatial locations). Without any explicit control of such misalignment inference is seriously compromised. Our objective is to assess the long-term effects of traffic noise on mortality in the city of Barcelona (Spain) during 2004-2007. We take into account the control of confounding, for both air pollution and socioeconomic factors at a contextual level and, in particular, we explicitly address the problem of misalignment. We employed a case-control design with individual data. We used deaths resulting from myocardial infarction, hypertension, or Type II diabetes mellitus in Barcelona between 2004 and 2007 as cases for the study, while for controls we used deaths (likewise in Barcelona and over the same period of time) resulting from AIDS or external causes (e.g. accidental falls, accidental poisoning by psychotropic drugs, drugs of abuse, suicide and self-harm, or injuries resulting from motor vehicle accidents). The controls were matched with the cases by sex and age. We used the annual average equivalent A-weighted sound pressure levels for daytime (7-21h), evening-time (21-23h) and night-time (23-7h), and controlled for the following confounders: i) air pollutants (NO2, PM10 and benzene), ii) material deprivation (at a census tract level) and iii) land use and other spatial variables. We explicitly controlled for heterogeneity (uneven distribution of both response and environmental exposures within an area), spatial dependency (of the observations of the response variables), temporal trends (long-term behaviour of the response variables) and spatial misalignment (between response and environmental exposure locations). We used a fully Bayesian method, through the Integrated Nested Laplace Approximation (INLA). Specifically, we plugged the whole model for the exposure into the health model and obtained a linear predictor defined on the entire spatial domain. Separate analyses were carried out for men and for women. After adjusting for confounders, we found that traffic noise was associated with myocardial infarction mortality along with Type II diabetes mellitus in men (in both cases, odds ratios (OR) were around 1.02) and mortality from hypertension in women (ORs around 1.01). Nevertheless, only in the case of hypertension in women, does the association remain statistically significant for all age groups considered (all ages, ≥65 years and ≥75 years).

Minimizing Air Pollution Exposure: A Practical Policy to Protect Vulnerable Older Adults from Death and Disability

Air pollution causes an estimated 200,000 deaths per year in the United States alone. Older adults are at greater risk of mortality caused by air pollution. Here we quantify the number of older adult facilities in Los Angeles County that are exposed to high levels of traffic derived air pollution, and propose policy solutions to reduce pollution exposure to this vulnerable subgroup. Distances between 20,362 intersections and 858 elder care facilities were estimated, and roads or highways within 500 of facilities were used to estimate traffic volume exposure. Of the 858 facilities, 54 were located near at least one major roadway, defined as a traffic volume over 100,000 cars/day. These 54 facilities house approximately 6,000 older adults. Following standards established for schools, we recommend legislation mandating the placement of new elder care facilities a minimum of 500 feet from major roadways in order to reduce unnecessary mortality risk from pollution exposure.

Noise Effects on Health in the Context of Air Pollution Exposure

For public health policy and planning it is important to understand the relative contribution of environmental noise on health compared to other environmental stressors. Air pollution is the primary environmental stressor in relation to cardiovascular morbidity and mortality. This paper reports a narrative review of studies in which the associations of both environmental noise and air pollution with health have been examined. Studies of hypertension, myocardial infarction, stroke, mortality and cognitive outcomes were included. Results suggest independent effects of environmental noise from road traffic, aircraft and, with fewer studies, railway noise on cardiovascular outcomes after adjustment for air pollution. Comparative burden of disease studies demonstrate that air pollution is the primary environmental cause of disability adjusted life years lost (DALYs). Environmental noise is ranked second in terms of DALYs in Europe and the DALYs attributed to noise were more than those attributed to lead, ozone and dioxins. In conclusion, in planning and health impact assessment environmental noise should be considered an independent contributor to health risk which has a separate and substantial role in ill-health separate to that of air pollution.

Noise Effects on Health in the Context of Air Pollution Exposure

For public health policy and planning it is important to understand the relative contribution of environmental noise on health compared to other environmental stressors. Air pollution is the primary environmental stressor in relation to cardiovascular morbidity and mortality. This paper reports a narrative review of studies in which the associations of both environmental noise and air pollution with health have been examined. Studies of hypertension, myocardial infarction, stroke, mortality and cognitive outcomes were included. Results suggest independent effects of environmental noise from road traffic, aircraft and, with fewer studies, railway noise on cardiovascular outcomes after adjustment for air pollution. Comparative burden of disease studies demonstrate that air pollution is the primary environmental cause of disability adjusted life years lost (DALYs). Environmental noise is ranked second in terms of DALYs in Europe and the DALYs attributed to noise were more than those attributed to lead, ozone and dioxins. In conclusion, in planning and health impact assessment environmental noise should be considered an independent contributor to health risk which has a separate and substantial role in ill-health separate to that of air pollution.

Environmental factors in cardiovascular disease

Environmental exposure is an important but underappreciated risk factor contributing to the development and severity of cardiovascular disease (CVD). The heart and vascular system are highly vulnerable to a number of environmental agents--ambient air pollution and the metals arsenic, cadmium, and lead are widespread and the most-extensively studied. Like traditional risk factors, such as smoking and diabetes mellitus, these exposures advance disease and mortality via augmentation or initiation of pathophysiological processes associated with CVD, including blood-pressure control, carbohydrate and lipid metabolism, vascular function, and atherogenesis. Although residence in highly polluted areas is associated with high levels of cardiovascular risk, adverse effects on cardiovascular health also occur at exposure levels below current regulatory standards. Considering the widespread prevalence of exposure, even modest contributions to CVD risk can have a substantial effect on population health. Evidence-based clinical and public-health strategies aimed at reducing environmental exposures from current levels could substantially lower the burden of CVD-related death and disability worldwide.

Residential proximity to major roadways and incident hypertension in post-menopausal women

Living near major roadways has been associated with increased risk of cardiovascular morbidity and mortality, presumably from exposure to elevated levels of traffic-related air and/or noise pollution. This association may potentially be mediated through increased risk of incident hypertension, but results from prior studies are equivocal. Using Cox proportional hazards models we examined residential proximity to major roadways and incident hypertension among 38,360 participants of the Women's Health Initiative (WHI) Clinical Trial cohorts free of hypertension at enrollment and followed for a median of 7.9 years. Adjusting for participant demographics and lifestyle, trial participation, and markers of individual and neighborhood socioeconomic status, the hazard ratios for incident hypertension were 1.13 (95% CI: 1.00, 1.28), 1.03 (0.95, 1.11), 1.05 (0.99, 1.11), and 1.05 (1.00, 1.10) for participants living ≤50, >50-200, >200-400, and >400-1000 m vs >1000 m from the nearest major roadway, respectively (ptrend=0.013). This association varied substantially by WHI study region with hazard ratios for women living ≤50 m from a major roadway of 1.61 (1.18, 2.20) in the West, 1.51 (1.22, 1.87) in the Northeast, 0.89 (0.70, 1.14) in the South, and 0.94 (0.75, 1.19) in the Midwest. In this large, national cohort of post-menopausal women, residential proximity to major roadways was associated with incident hypertension in selected regions of the U.S. If causal, these results suggest residential proximity to major roadways, as a marker for air, noise and other traffic-related pollution, may be a risk factor for hypertension.

ICBEN review of research on the biological effects of noise 2011-2014

The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health.

Health impact assessment of traffic noise in Madrid (Spain)

The relationship between environmental noise and health has been examined in depth. In view of the sheer number of persons exposed, attention should be focused on road traffic noise. The city of Madrid (Spain) is a densely populated metropolitan area in which 80% of all environmental noise exposure is attributed to traffic. The aim of this study was to quantify avoidable deaths resulting from reducing the impact of equivalent diurnal noise levels (LeqD) on daily cardiovascular and respiratory mortality among people aged ≥65 years in Madrid. A health impact assessment of (average 24h) LeqD and PM2.5 levels was conducted by using previously reported risk estimates of mortality rates for the period 2003-2005: For cardiovascular causes: LeqD 1.048 (1.005, 1.092) and PM2.5 1.041(1.020, 1.062) and for respiratory causes: LeqD 1.060 (1.000, 1.123) and PM2.5 1.030 (1.000, 1.062). The association found between LeqD exposure and mortality for both causes suggests an important health effect. A reduction of 1dB(A) in LeqD implies an avoidable annual mortality of 284 (31, 523) cardiovascular- and 184 (0, 190) respiratory-related deaths in the study population. The magnitude of the health impact is similar to reducing average PM2.5 levels by 10µg/m(3). Regardless of air pollution, exposure to traffic noise should be considered an important environmental factor having a significant impact on health.

In-vehicle exposures to particulate air pollution in Canadian metropolitan areas: the urban transportation exposure study

Commuters may be exposed to increased levels of traffic-related air pollution owing to close proximity to traffic-emissions. We collected in-vehicle and roof-top air pollution measurements over 238 commutes in Montreal, Toronto, and Vancouver, Canada between 2010 and 2013. Voice recordings were used to collect real-time information on traffic density and the presence of diesel vehicles and multivariable linear regression models were used to estimate the impact of these factors on in-vehicle pollutant concentrations (and indoor/outdoor ratios) along with parameters for road type, land use, and meteorology. In-vehicle PM2.5 and NO2 concentrations consistently exceeded regional outdoor levels and each unit increase in the rate of encountering diesel vehicles (count/min) was associated with substantial increases (>100%) in in-vehicle concentrations of ultrafine particles (UFPs), black carbon, and PM2.5 as well as strong increases (>15%) in indoor/outdoor ratios. A model based on meteorology and the length of highway roads within a 500 m buffer explained 53% of the variation in in-vehicle UFPs; however, models for PM2.5 (R(2) = 0.24) and black carbon (R(2) = 0.30) did not perform as well. Our findings suggest that vehicle commuters experience increased exposure to air pollutants and that traffic characteristics, land use, road types, and meteorology are important determinants of these exposures.

Exposure to traffic-related air pollution during physical activity and acute changes in blood pressure, autonomic and micro-vascular function in women: a cross-over study

BACKGROUND

Traffic-related air pollution may contribute to cardiovascular morbidity. In urban areas, exposures during physical activity are of interest owing to increased breathing rates and close proximity to vehicle emissions.

METHODS

We conducted a cross-over study among 53 healthy non-smoking women in Montreal, Canada during the summer of 2013. Women were exposed to traffic pollutants for 2-hours on three separate occasions during cycling on high and low-traffic routes as well as indoors. Personal air pollution exposures (PM(2.5), ultrafine particles (UFP), black carbon, NO₂, and O₃) were evaluated along each route and linear mixed-effects models with random subject intercepts were used to estimate the impact of air pollutants on acute changes in blood pressure, heart rate variability, and micro-vascular function in the hours immediately following exposure. Single and multi-pollutant models were examined and potential effect modification by mean regional air pollution concentrations (PM(2.5), NO₂, and O₃) was explored for the 24-hour and 5-day periods preceding exposure.

RESULTS

In total, 143 exposure routes were completed. Each interquartile increase (10,850/cm³) in UFP exposure was associated with a 4.91% (95% CI: -9.31, -0.512) decrease in reactive hyperemia index (a measure of micro-vascular function) and each 24 ppb increase in O₃ exposure corresponded to a 2.49% (95% CI: 0.141, 4.84) increase in systolic blood pressure and a 3.26% (95% CI: 0.0117, 6.51) increase in diastolic blood pressure 3-hours after exposure. Personal exposure to PM(2.5) was associated with decreases in HRV measures reflecting parasympathetic modulation of the heart and regional PM(2.5) concentrations modified these relationships (p < 0.05). In particular, stronger inverse associations were observed when regional PM(2.5) was higher on the days prior to the study period. Regional PM(2.5) also modified the impact of personal O₃ on the standard deviation of normal to normal intervals (SDNN) (p < 0.05): a significant inverse relationship was observed when regional PM(2.5) was low prior to study periods and a significant positive relationship was observed when regional PM(2.5) was high.

CONCLUSION

Exposure to traffic pollution may contribute to acute changes in blood pressure, autonomic and micro-vascular function in women. Regional air pollution concentrations may modify the impact of these exposures on autonomic function.

Roadway proximity and risk of sudden cardiac death in women

BACKGROUND

Sudden cardiac death (SCD) is a major source of mortality and is the first manifestation of heart disease for the majority of cases. Thus, there is a definite need to identify risk factors for SCD that can be modified at the population level. Exposure to traffic, measured by residential roadway proximity, has been shown to be associated with an increased risk of cardiovascular disease. Our objective was to determine whether roadway proximity was associated with an increased risk of SCD and to compare that risk with the risk of other coronary heart disease outcomes.

METHODS AND RESULTS

A total of 523 cases of SCD were identified over 26 years of follow-up among 107 130 members of the prospective Nurses' Health Study. We calculated residential distance to roadways at all residential addresses from 1986 to 2012. In age- and race-adjusted models, women living within 50 m of a major roadway had an elevated risk of SCD (hazard ratio=1.56; 95% confidence interval, 1.18-2.05). The association was attenuated but still statistically significant after controlling for potential confounders and mediators (hazard ratio=1.38; 95% confidence interval, 1.04-1.82). The equivalent adjusted hazard ratios for nonfatal myocardial infarction and fatal coronary heart disease were 1.08 (95% confidence interval, 0.96-1.23) and 1.24 (95% confidence interval, 1.03-1.50), respectively.

CONCLUSIONS

Among this sample of middle-aged and older women, roadway proximity was associated with elevated and statistically significant risks of SCD and fatal coronary heart disease, even after controlling for other cardiovascular risk factors.

Noise levels and cardiovascular mortality: a case-crossover analysis

BACKGROUND

The relationship between occupational noise and cardiovascular outcomes has been widely investigated. Regarding environmental noise levels, the attention is focused on road traffic noise due to the large number of exposed persons and the large periods of exposure. There are few studies assessing the short-term effects of traffic noise on cardiovascular outcomes. The aim of this study was to quantify the short-term effects of urban noise levels on age-specific cardiovascular mortality.

METHODS

A case-crossover design was used. Daily mortality counts in Madrid city due to cardiovascular causes (ICD codes: 390-459) from 1 January 2003 to 31 December 2005 were obtained. Data noise levels were collected as diurnal equivalent noise (Leqd8-22 h), night equivalent noise (Leqn22-8 h), and daily equivalent noise (Leq24 h). Confounding variables as daily levels of air pollutants, temperature, and relative humidity data were controlled. Overdispersed Poisson regression models were adjusted to control for both seasonality and time trends. Estimated effects are reported as percentage increase in the relative risk (IRR) associated with an increase of 1 dBA.

RESULTS

The strongest associations between all noise exposure levels and cardiovascular mortality were reported at lag 1: IRR 4.5% (95% CI 0.6, 8.7%), IRR 3.9% (95% CI 0.6, 7.3%), and IRR 6.2% (95% CI 2.1, 10.6%) for Leqd, Leqn, and Leq24, respectively. Analysing by age-specific groups at lag 1, statistically significant associations were found for those aged ≥65: 4.5% (95% CI 0.3, 8.9%), 3.4% (95% CI 0.1, 6.9%), and 6.6% (95% CI 2.2, 11.1%) for Leqd, Leqn, and Leq24, with no substantial changes in the effects of noise exposure levels at lag 1 after adjusting for PM2.5 and NO2.

CONCLUSION

The association found between noise exposure levels and cardiovascular mortality suggests a joint effect of diurnal and night-time noise levels. Our results also reveal independent effects of noise exposure levels and the air pollutants analysed. This strongly suggests the need to seriously consider the high noise exposure levels reported as an important public health issue.

Potential public health hazards, exposures and health effects from unconventional natural gas development

The rapid increase in unconventional natural gas (UNG) development in the United States during the past decade has brought wells and related infrastructure closer to population centers. This review evaluates risks to public health from chemical and nonchemical stressors associated with UNG, describes likely exposure pathways and potential health effects, and identifies major uncertainties to address with future research. The most important occupational stressors include mortality, exposure to hazardous materials and increased risk of industrial accidents. For communities near development and production sites the major stressors are air pollutants, ground and surface water contamination, truck traffic and noise pollution, accidents and malfunctions, and psychosocial stress associated with community change. Despite broad public concern, no comprehensive population-based studies of the public health effects of UNG operations exist. Major uncertainties are the unknown frequency and duration of human exposure, future extent of development, potential emission control and mitigation strategies, and a paucity of baseline data to enable substantive before and after comparisons for affected populations and environmental media. Overall, the current literature suggests that research needs to address these uncertainties before we can reasonably quantify the likelihood of occurrence or magnitude of adverse health effects associated with UNG production in workers and communities.