Estimation of Short-Term Effects of Air Pollution on Stroke Hospital Admissions in Wuhan,China

Background and Objective

High concentrations of air pollutants have been linked to increased incidence of stroke in North America and Europe but not yet assessed in mainland China. The aim of this study is to evaluate the association between stroke hospitalization and short-term elevation of air pollutants in Wuhan, China.

Methods

Daily mean NO₂, SO₂ and PM₁₀ levels, temperature and humidity were obtained from 2006 through 2008. Data on stroke hospitalizations (ICD 10: I60–I69) at four hospitals in Wuhan were obtained for the same period. A time-stratified case-crossover design was performed by season (April-September and October-March) to assess effects of pollutants on stroke hospital admissions.

Results

Pollution levels were higher in October-March with averages of 136.1 µg/m³ for PM₁₀, 63.6 µg/m³ for NO₂ and 71.0 µg/m³ for SO₂ than in April-September when averages were 102.0 µg/m³, 41.7 µg/m³ and 41.7 µg/m³, respectively (p<.001). During the cold season, every 10 µg/m³ increase in NO₂ was associated with a 2.9% (95%C.I. 1.2%–4.6%) increase in stroke admissions on the same day. Every 10 ug/m³ increase in PM₁₀ daily concentration was significantly associated with an approximate 1% (95% C.I. 0.1%–1.4%) increase in stroke hospitalization. A two-pollutant model indicated that NO₂ was associated with stroke admissions when controlling for PM₁₀. During the warm season, no significant associations were noted for any of the pollutants.

Conclusions

Exposure to NO₂ is significantly associated with stroke hospitalizations during the cold season in Wuhan, China when pollution levels are 50% greater than in the warm season. Larger and multi-center studies in Chinese cities are warranted to validate our findings.     

The Association between Ambient Air Pollution and Daily Mortality in Beijing after the 2008 Olympics: A Time Series Study

In recent decades, ambient air pollution has been an important public health issue in Beijing, but little is known about air pollution and health effects after the 2008 Beijing Olympics. We conduct a time-series analysis to evaluate associations between daily mortality (nonaccidental, cardiovascular and respiratory mortality) and the major air pollutants (carbon monoxide, nitrogen dioxide and particulate matter less than 10 µm in aerodynamic diameter) in Beijing during the two years (2009∼2010) after the 2008 Beijing Olympics. We used generalized additive model to analyze relationship between daily mortality and air pollution. In single air pollutant model with two-day moving average concentrations of the air pollutants, increase in their interquartile range (IQR) associated with percent increase in nonaccidental mortality, 2.55 percent [95% confidence interval (CI): 1.99, 3.11] for CO, 2.54 percent (95% CI: 2.00, 3.08) for NO₂ and 1.80 percent (95% CI: 1.21, 2.40) for PM₁₀, respectively; increases in the IQR of air pollutant concentrations associated with percent increase in cardiovascular mortality, 2.88 percent (95% CI: 2.10,3.65) for CO, 2.63 percent (95% CI: 1.87, 3.39) for NO₂ and 1.72 percent (95% CI: 0.88, 2.55) for PM₁₀, respectively; and increase in IQR of air pollutant concentrations associated with respiratory mortality, 2.39 percent (95% CI: 0.68, 4.09) for CO, 1.79 percent (95% CI: 0.11, 3.47) for NO₂ and 2.07 percent (95% CI: 0.21, 3.92) for PM₁₀, respectively. We used the principal component analysis to avoid collinearity of varied air pollutants. In addition, the association stratified by sex and age was also examined. Ambient air pollution remained a significant contributor to nonaccidental and cardiopulmonary mortalities in Beijing during 2009∼2010.     

Prenatal Air Pollution Exposure and Early Cardiovascular Phenotypes in Young Adults

Exposure to ambient air pollutants increases risk for adverse cardiovascular health outcomes in adults. We aimed to evaluate the contribution of prenatal air pollutant exposure to cardiovascular health, which has not been thoroughly evaluated. The Testing Responses on Youth (TROY) study consists of 768 college students recruited from the University of Southern California in 2007–2009. Participants attended one study visit during which blood pressure, heart rate and carotid artery arterial stiffness (CAS) and carotid artery intima-media thickness (CIMT) were assessed. Prenatal residential addresses were geocoded and used to assign prenatal and postnatal air pollutant exposure estimates using the U.S. Environmental Protection Agency’s Air Quality System (AQS) database. The associations between CAS, CIMT and air pollutants were assessed using linear regression analysis. Prenatal PM₁₀ and PM_2.5 exposures were associated with increased CAS. For example, a 2 SD increase in prenatal PM_2.5 was associated with CAS indices, including a 5% increase (β = 1.05, 95% CI 1.00–1.10) in carotid stiffness index beta, a 5% increase (β = 1.05, 95% CI 1.01–1.10) in Young’s elastic modulus and a 5% decrease (β = 0.95, 95% CI 0.91–0.99) in distensibility. Mutually adjusted models of pre- and postnatal PM_2.5 further suggested the prenatal exposure was most relevant exposure period for CAS. No associations were observed for CIMT. In conclusion, prenatal exposure to elevated air pollutants may increase carotid arterial stiffness in a young adult population of college students. Efforts aimed at limiting prenatal exposures are important public health goals.     

The impact of outdoor air pollutants on outpatient visits for respiratory diseases during 2012–2016 in Jinan,China

Background

Few studies have investigated the associations between outdoor air pollution and outpatient visits for respiratory diseases (RDs) in general population.

Methods

We collected daily outpatient data of primary RDs from five hospitals in Jinan during January 2012 and December 2016, as well as daily measurements of air pollutants from the Jinan Environmental Monitoring Center and daily meteorological variables from the China Meteorological Data Sharing Service System. A generalized additive model (GAM) with quasi-Poisson regression was constructed to estimate the associations between daily average concentrations of outdoor air pollutants (PM_2.5,PM₁₀, SO₂, NO₂, CO and O₃) and daily outpatient visits of RDs after adjusting for long-time trends, seasonality, the “day of the week” effect, and weather conditions. Subgroup analysis stratified by gender, age group and the type of RDs was conducted.

Results

A total of 1,373,658 outpatient visits for RDs were identified. Increases of 10?μg/m³ in PM_2.5, PM₁₀, NO₂, CO and O₃ were associated with0.168% (95% CI, 0.072–0.265%), 0.149% (95% CI, 0.082–0.215%), 0.527% (95% CI, 0.211–0.843%), 0.013% (95% CI, 0.003–0.023%), and 0.189% (95% CI, 0.032–0.347%) increases in daily outpatient visits for RDs, respectively. PM_2.5 and PM₁₀ showed instant and continuous effects, while NO₂, CO and O₃ showed delayed effects on outpatient visits for RDs. In stratification analysis, PM_2.5 and PM₁₀ were associated with acute RDs only.

Conclusions

Exposure to outdoor air pollutants including PM_2.5, PM₁₀, NO₂, CO and O₃ associated with increased risk of outpatient visits for RDs.

     

Obesity and the relation between joint exposure to ambient air pollutants and incident type 2 diabetes: A cohort study in UK Biobank

BackgroundAir pollution has been related to incidence of type 2 diabetes (T2D). We assessed the joint association of various air pollutants with the risk of T2D and examined potential modification by obesity status and genetic susceptibility on the relationship.Methods and findingsA total of 449,006 participants from UK Biobank free of T2D at baseline were included. Of all the study population, 90.9% were white and 45.7% were male. The participants had a mean age of 56.6 (SD 8.1) years old and a mean body mass index (BMI) of 27.4 (SD 4.8) kg/m². Ambient air pollutants, including particulate matter (PM) with diameters ≤2.5 μm (PM_2.5), between 2.5 μm and 10 μm (PM_2.5–10), nitrogen dioxide (NO₂), and nitric oxide (NO) were measured. An air pollution score was created to assess the joint exposure to the 4 air pollutants. During a median of 11 years follow-up, we documented 18,239 incident T2D cases. The air pollution score was significantly associated with a higher risk of T2D. Compared to the lowest quintile of air pollution score, the hazard ratio (HR) (95% confidence interval [CI]) for T2D was 1.05 (0.99 to 1.10, p = 0.11), 1.06 (1.00 to 1.11, p = 0.051), 1.09 (1.03 to 1.15, p = 0.002), and 1.12 (1.06 to 1.19, p < 0.001) for the second to fifth quintile, respectively, after adjustment for sociodemographic characteristics, lifestyle factors, genetic factors, and other covariates. In addition, we found a significant interaction between the air pollution score and obesity status on the risk of T2D (p-interaction < 0.001). The observed association was more pronounced among overweight and obese participants than in the normal-weight people. Genetic risk score (GRS) for T2D or obesity did not modify the relationship between air pollution and risk of T2D. Key study limitations include unavailable data on other potential T2D-related air pollutants and single-time measurement on air pollutants.ConclusionsWe found that various air pollutants PM_2.5, PM_2.5–10, NO_2, and NO, individually or jointly, were associated with an increased risk of T2D in the population. The stratified analyses indicate that such associations were more strongly associated with T2D risk among those with higher adiposity.

Xiang Li and co-workers study the potential influence of obesity on associations between air pollutants and incidence of type 2 diabetes.     

Long-term exposure to ambient air pollution and mortality due to cardiovascular disease and cerebrovascular disease in Shenyang, China

Background

The relationship between ambient air pollution exposure and mortality of cardiovascular and cerebrovascular diseases in human is controversial, and there is little information about how exposures to ambient air pollution contribution to the mortality of cardiovascular and cerebrovascular diseases among Chinese. The aim of the present study was to examine whether exposure to ambient-air pollution increases the risk for cardiovascular and cerebrovascular disease.

Methodology/Principal Findings

We conducted a retrospective cohort study among humans to examine the association between compound-air pollutants [particulate matter <10 µm in aerodynamic diameter (PM₁₀), sulfur dioxide (SO₂) and nitrogen dioxide (NO₂)] and mortality in Shenyang, China, using 12 years of data (1998–2009). Also, stratified analysis by sex, age, education, and income was conducted for cardiovascular and cerebrovascular mortality. The results showed that an increase of 10 µg/m³ in a year average concentration of PM₁₀ corresponds to 55% increase in the risk of a death cardiovascular disease (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.51 to 1.60) and 49% increase in cerebrovascular disease (HR, 1.49; 95% CI, 1.45 to 1.53), respectively. The corresponding figures of adjusted HR (95%CI) for a 10 µg/m³ increase in NO₂ was 2.46 (2.31 to 2.63) for cardiovascular mortality and 2.44 (2.27 to 2.62) for cerebrovascular mortality, respectively. The effects of air pollution were more evident in female that in male, and nonsmokers and residents with BMI<18.5 were more vulnerable to outdoor air pollution.

Conclusion/Significance

Long-term exposure to ambient air pollution is associated with the death of cardiovascular and cerebrovascular diseases among Chinese populations.     

Acute Effects of Particulate Matter and Black Carbon from Seasonal Fires on Peak Expiratory Flow of Schoolchildren in the Brazilian Amazon

Background

Panel studies have shown adverse effects of air pollution from biomass burning on children''s health. This study estimated the effect of current levels of outdoor air pollution in the Amazonian dry season on peak expiratory flow (PEF).

Methods

A panel study with 234 schoolchildren from 6 to 15 years old living in the municipality of Tangará da Serra, Brazil was conducted. PEF was measured daily in the dry season in 2008. Mixed-effects models and unified modelling repeated for every child were applied. Time trends, temperature, humidity, and subject characteristics were regarded. Inhalable particulate matter (PM₁₀), fine particulate matter (PM_2.5), and black carbon (BC) effects were evaluated based on 24-hour exposure lagged by 1 to 5 days and the averages of 2 or 3 days. Polynomial distributed lag models (PDLM) were also applied.

Results

The analyses revealed reductions in PEF for PM₁₀ and PM_2.5 increases of 10 µg/m³ and 1 µg/m³ for BC. For PM₁₀, the reductions varied from 0.15 (confidence interval (CI)95%: −0.29; −0.01) to 0.25 l/min (CI95%: −0.40; −0.10). For PM_2.5, they ranged from 0.46 (CI95%: −0.86 to −0.06) to 0.54 l/min (CI95%:−0.95; −0.14). As for BC, the reduction was approximately 1.40 l/min. In relation to PDLM, adverse effects were noticed in models based on the exposure on the current day through the previous 3 days (PDLM 0–3) and on the current day through the previous 5 days (PDLM 0–5), specially for PM₁₀. For all children, for PDLM 0–5 the global effect was important for PM₁₀, with PEF reduction of 0.31 l/min (CI95%: −0.56; −0.05). Also, reductions in lags 3 and 4 were observed. These associations were stronger for children between 6 and 8 years old.

Conclusion

Reductions in PEF were associated with air pollution, mainly for lagged exposures of 3 to 5 days and for younger children.     

Association between Air Pollution and General Outpatient Clinic Consultations for Upper Respiratory Tract Infections in Hong Kong

Background and Objectives

Many studies have shown the adverse effects of air pollution on respiratory health, but few have examined the effects of air pollution on service utilisation in the primary care setting. The aim of this study was to examine the association between air pollution and the daily number of consultations due to upper respiratory tract infections (URTIs) in general outpatient clinics (GOPCs) in Hong Kong.

Methods

Daily data on the numbers of consultations due to URTIs in GOPCs, the concentrations of major air pollutants, and the mean values of metrological variables were retrospectively collected over a 3-year period (2008–2010, inclusive). Generalised additive models were constructed to examine the association between air pollution and the daily number of consultations, and to derive the relative risks and 95% confidence intervals (95% CI) of GOPC consultations for a unit increase in the concentrations of air pollutants.

Results

The mean daily consultations due to URTIs in GOPCs ranged from 68.4 to 253.0 over the study period. The summary relative risks (and 95% CI) of daily consultations in all GOPCs for the air pollutants PM₁₀, NO₂, O₃, and SO₂ were 1.005 (1.002, 1.009), 1.010 (1.006, 1.013), 1.009 (1.006, 1.012), and 1.004 (1.000, 1.008) respectively, per 10 µg/m³ increase in the concentration of each pollutant.

Conclusion

Significant associations were found between the daily number of consultations due to URTIs in GOPCs and the concentrations of air pollutants, implying that air pollution incurs a substantial morbidity and increases the burden of primary health care services.     

Gender differences and effect of air pollution on asthma in children with and without allergic predisposition: northeast Chinese children health study

Background

Males and females exhibit different health responses to air pollution, but little is known about how exposure to air pollution affects juvenile respiratory health after analysis stratified by allergic predisposition. The aim of the present study was to assess the relationship between air pollutants and asthmatic symptoms in Chinese children selected from multiple sites in a heavily industrialized province of China, and investigate whether allergic predisposition modifies this relationship.

Methodology/Principal Findings

30139 Chinese children aged 3-to-12 years were selected from 25 districts of seven cities in northeast China in 2009. Information on respiratory health was obtained using a standard questionnaire from the American Thoracic Society. Routine air-pollution monitoring data was used for particles with an aerodynamic diameter ≤10 µm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxides (NO₂), ozone (O₃) and carbon monoxide (CO). A two-stage regression approach was applied in data analyses. The effect estimates were presented as odds ratios (ORs) per interquartile changes for PM₁₀, SO₂, NO₂, O₃, and CO. The results showed that children with allergic predisposition were more susceptible to air pollutants than children without allergic predisposition. Amongst children without an allergic predisposition, air pollution effects on asthma were stronger in males compared to females; Current asthma prevalence was related to PM₁₀ (ORs = 1.36 per 31 µg/m³; 95% CI, 1.08–1.72), SO₂ (ORs = 1.38 per 21 µg/m³; 95%CI, 1.12–1.69) only among males. However, among children with allergic predisposition, more positively associations between air pollutants and respiratory symptoms and diseases were detected in females; An increased prevalence of doctor-diagnosed asthma was significantly associated with SO₂ (ORs = 1.48 per 21 µg/m³; 95%CI, 1.21–1.80), NO₂ (ORs = 1.26 per 10 µg/m³; 95%CI, 1.01–1.56), and current asthma with O₃ (ORs = 1.55 per 23 µg/m³; 95%CI, 1.18–2.04) only among females.

Conclusion/Significance

Ambient air pollutions were more evident in males without an allergic predisposition and more associations were detected in females with allergic predisposition.     

Effects of Air Pollution and the Introduction of the London Low Emission Zone on the Prevalence of Respiratory and Allergic Symptoms in Schoolchildren in East London: A Sequential Cross-Sectional Study

The adverse effects of traffic-related air pollution on children’s respiratory health have been widely reported, but few studies have evaluated the impact of traffic-control policies designed to reduce urban air pollution. We assessed associations between traffic-related air pollutants and respiratory/allergic symptoms amongst 8–9 year-old schoolchildren living within the London Low Emission Zone (LEZ). Information on respiratory/allergic symptoms was obtained using a parent-completed questionnaire and linked to modelled annual air pollutant concentrations based on the residential address of each child, using a multivariable mixed effects logistic regression analysis. Exposure to traffic-related air pollutants was associated with current rhinitis: NOx (OR 1.01, 95% CI 1.00–1.02), NO₂ (1.03, 1.00–1.06), PM₁₀ (1.16, 1.04–1.28) and PM_2.5 (1.38, 1.08–1.78), all per μg/m³ of pollutant, but not with other respiratory/allergic symptoms. The LEZ did not reduce ambient air pollution levels, or affect the prevalence of respiratory/allergic symptoms over the period studied. These data confirm the previous association between traffic-related air pollutant exposures and symptoms of current rhinitis. Importantly, the London LEZ has not significantly improved air quality within the city, or the respiratory health of the resident population in its first three years of operation. This highlights the need for more robust measures to reduce traffic emissions.     

The Novel Relationship between Urban Air Pollution and Epilepsy: A Time Series Study

MethodsA hospital record-based study was carried out in Xi’an, a heavily-polluted metropolis in China. Daily baseline data were obtained. Time-series Poisson regression models were applied to analyze the association between air pollution and epilepsy.ResultsA 10 μg/m³ increase of NO₂, SO₂, and O₃ concentrations corresponded to 3.17% (95%Cl: 1.41%, 4.93%), 3.55% (95%Cl: 1.93%, 5.18%), and -0.84% (95%Cl: -1.58%, 0.09%) increase in outpatient-visits for epilepsy on the concurrent days, which were significantly influenced by sex and age. The effects of NO₂ and SO₂ would be stronger when adjusted for PM_2.5. As for O₃, a -1.14% (95%Cl: -1.90%, -0.39%) decrease was evidenced when adjusted for NO₂. The lag models showed that the most significant effects were evidenced on concurrent days.ConclusionsWe discovered previously undocumented relationships between short-term air pollution exposure and epilepsy: while NO₂ and SO₂ were positively associated with outpatient-visits of epilepsy, O₃ might be associated with reduced risk.     

How air pollution influences clinical management of respiratory diseases. A case-crossover study in Milan

Background

Environmental pollution is a known risk factor for multiple diseases and furthermore increases rate of hospitalisations. We investigated the correlation between emergency room admissions (ERAs) of the general population for respiratory diseases and the environmental pollutant levels in Milan, a metropolis in northern Italy.

Methods

We collected data from 45770 ERAs for respiratory diseases. A time-stratified case-crossover design was used to investigate the association between air pollution levels and ERAs for acute respiratory conditions. The effects of air pollutants were investigated at lag 0 to lag 5, lag 0–2 and lag 3–5 in both single and multi-pollutant models, adjusted for daily weather variables.

Results

An increase in ozone (O₃) levels at lag 3–5 was associated with a 78% increase in the number of ERAs for asthma, especially during the warm season. Exposure to carbon monoxide (CO) proved to be a risk factor for pneumonia at lag 0–2 and in the warm season increased the risk of ERA by 66%. A significant association was found between ERAs for COPD exacerbation and levels of sulphur dioxide (SO₂), CO, nitrate dioxide (NO₂), and particulate matter (PM₁₀ and PM_2.5). The multipollutant model that includes all pollutants showed a significant association between CO (26%) and ERA for upper respiratory tract diseases at lag 0–2. For chronic obstructive pulmonary disease (COPD) exacerbations, only CO (OR 1.19) showed a significant association.

Conclusions

Exposure to environmental pollution, even at typical low levels, can increase the risk of ERA for acute respiratory diseases and exacerbation of obstructive lung diseases in the general population.     

Long-term air pollution exposure and living close to busy roads are associated with COPD in women

Background

Lung function and exacerbations of chronic obstructive pulmonary disease (COPD) have been associated with short-term exposure to air pollution. However, the effect of long-term exposure to particulate matter from industry and traffic on COPD as defined by lung function has not been evaluated so far. Our study was designed to investigate the influence of long-term exposure to air pollution on respiratory symptoms and pulmonary function in 55-year-old women. We especially focused on COPD as defined by GOLD criteria and additionally compared the effects of air pollution on respiratory symptoms by questionnaire data and by lung function measurements.

Methods

In consecutive cross sectional studies conducted between 1985–1994, we investigated 4757 women living in the Rhine-Ruhr Basin of Germany. NO₂ and PM₁₀ exposure was assessed by measurements done in an 8 km grid, and traffic exposure by distance from the residential address to the nearest major road using Geographic Information System data. Lung function was determined and COPD was defined by using the GOLD criteria. Chronic respiratory symptoms and possible confounders were defined by questionnaire data. Linear and logistic regressions, including random effects were used to account for confounding and clustering on city level.

Results

The prevalence of COPD (GOLD stages 1–4) was 4.5%. COPD and pulmonary function were strongest affected by PM₁₀ and traffic related exposure. A 7 μg/m₃ increase in five year means of PM₁₀ (interquartile range) was associated with a 5.1% (95% CI 2.5%–7.7%) decrease in FEV₁, a 3.7% (95% CI 1.8%–5.5%) decrease in FVC and an odds ratio (OR) of 1.33 (95% CI 1.03–1.72) for COPD. Women living less than 100 m from a busy road also had a significantly decreased lung function and COPD was 1.79 times more likely (95% CI 1.06–3.02) than for those living farther away. Chronic symptoms as based on questionnaire information showed effects in the same direction, but less pronounced.

Conclusion

Chronic exposure to PM₁₀, NO₂ and living near a major road might increase the risk of developing COPD and can have a detrimental effect on lung function.     

Fine Particulate Air Pollution and Hospital Emergency Room Visits for Respiratory Disease in Urban Areas in Beijing,China, in 2013

BackgroundHeavy fine particulate matter (PM_2.5) air pollution occurs frequently in China. However, epidemiological research on the association between short-term exposure to PM_2.5 pollution and respiratory disease morbidity is still limited. This study aimed to explore the association between PM_2.5 pollution and hospital emergency room visits (ERV) for total and cause-specific respiratory diseases in urban areas in Beijing.MethodsDaily counts of respiratory ERV from Jan 1 to Dec 31, 2013, were obtained from ten general hospitals located in urban areas in Beijing. Concurrently, data on PM_2.5 were collected from the Beijing Environmental Protection Bureau, including 17 ambient air quality monitoring stations. A generalized-additive model was used to explore the respiratory effects of PM_2.5, after controlling for confounding variables. Subgroup analyses were also conducted by age and gender.ResultsA total of 92,464 respiratory emergency visits were recorded during the study period. The mean daily PM_2.5 concentration was 102.1±73.6 μg/m³. Every 10 μg/m³ increase in PM_2.5 concentration at lag₀ was associated with an increase in ERV, as follows: 0.23% for total respiratory disease (95% confidence interval [CI]: 0.11%-0.34%), 0.19% for upper respiratory tract infection (URTI) (95%CI: 0.04%-0.35%), 0.34% for lower respiratory tract infection (LRTI) (95%CI: 0.14%-0.53%) and 1.46% for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) (95%CI: 0.13%-2.79%). The strongest association was identified between AECOPD and PM_2.5 concentration at lag_0-3 (3.15%, 95%CI: 1.39%-4.91%). The estimated effects were robust after adjusting for SO₂, O₃, CO and NO₂. Females and people 60 years of age and older demonstrated a higher risk of respiratory disease after PM_2.5 exposure.ConclusionPM_2.5 was significantly associated with respiratory ERV, particularly for URTI, LRTI and AECOPD in Beijing. The susceptibility to PM_2.5 pollution varied by gender and age.     

Comparison of the Effects of Air Pollution on Outpatient and Inpatient Visits for Asthma: A Population-Based Study in Taiwan

Background

A nationwide asthma survey on the effects of air pollution is lacking in Taiwan. The purpose of this study was to evaluate the time trend and the relationship between air pollution and health care services for asthma in Taiwan.

Methods

Health care services for asthma and ambient air pollution data were obtained from the National Health Insurance Research database and Environmental Protection Administration from 2000 through 2009, respectively. Health care services, including those related to the outpatient and inpatient visits were compared according to the concentration of air pollutants.

Results

The number of asthma-patient visits to health-care facilities continue to increase in Taiwan. Relative to the respective lowest quartile of air pollutants, the adjusted relative risks (RRs) of the outpatient visits in the highest quartile were 1.10 (P-trend  = 0.013) for carbon monoxide (CO), 1.10 (P-trend  = 0.015) for nitrogen dioxide (NO₂), and 1.20 (P-trend <0.0001) for particulate matter with an aerodynamic diameter ≦10µm (PM₁₀) in the child group (aged 0–18). For adults aged 19–44, the RRs of outpatient visits were 1.13 (P-trend = 0.078) for CO, 1.17 (P-trend = 0.002) for NO_2, and 1.13 (P-trend <0.0001) for PM₁₀. For adults aged 45–64, the RRs of outpatient visits were 1.15 (P-trend = 0.003) for CO, 1.19 (P-trend = 0.0002) for NO_2, and 1.10 (P-trend = 0.001) for PM₁₀. For the elderly (aged≥ 65), the RRs of outpatient visits in were 1.12 (P-trend  = 0.003) for NO₂ and 1.10 (P-trend  = 0.006) for PM_10. For inpatient visits, the RRs across quartiles of CO level were 1.00, 1.70, 1.92, and 1.86 (P-trend  = 0.0001) in the child group. There were no significant linear associations between inpatient visits and air pollutants in other groups.

Conclusions

There were positive associations between CO levels and childhood inpatient visits as well as NO₂, CO and PM₁₀ and outpatient visits.     

Air quality modeling for health risk assessment of ambient PM10, PM2.5 and SO2 in Iran

In this study, we have estimated the number of total mortality (T-mortality), cardiovascular morbidity (CV-mortality), respiratory mortality (R-mortality), hospital admissions due to cardiovascular diseases (HA-CVD), respiratory diseases (HA-RD), chronic obstructive pulmonary diseases (COPD) and acute myocardial infarction (AMI) due to exposure to particulate matter less than 10 µm (PM₁₀), 2.5 µm (PM_2.5) and sulfur dioxide (SO₂) in western Iran in 2016. The World Health Organization (WHO) method was used to assess the mortality and morbidity among the exposed people. The results showed that about 3.9% CM (95% CI: 2.9–7.8%), 3.9% HA-RD (95% CI: 2.4–7.8%) and 4.4% HA-CVD (95% CI: 3.0–6.8%) for ambient PM₁₀ and about 7.3% TM (95% CI: 4.2–9.7%), 12.1% CM (95% CI: 3.5–14.6%) and 3.0% RM (95% CI: 0–6.3%) for PM_2.5 are respectively attributed to concentrations exceeding 10 µg/m³. Furthermore, 3.2% HA-COPD (95% CI: 0–5.04%) and 4.2% AMI (95% CI: 1.6–4.3%) can be attributed to SO₂ concentrations greater than 10 µg/m³, respectively. To reduce the adverse health effect of PM, health advices provided by health authorities should be given to general population especially vulnerable people such as people with chronic lung and heart pathologies, elderly and children during the dusty days.     

A Longitudinal Study of Sick Building Syndrome (SBS) among Pupils in Relation to SO2, NO2, O3 and PM10 in Schools in China

There are fewer longitudinal studies from China on symptoms as described for the sick building syndrome (SBS). Here, we performed a two-year prospective study and investigated associations between environmental parameters such as room temperature, relative air humidity (RH), carbon dioxide (CO₂), nitrogen dioxide (NO₂), sulphur dioxide (SO₂), ozone (O₃), particulate matter (PM₁₀), and health outcomes including prevalence, incidence and remission of SBS symptoms in junior high schools in Taiyuan, China. Totally 2134 pupils participated at baseline, and 1325 stayed in the same classrooms during the study period (2010–2012). The prevalence of mucosal symptoms, general symptoms and symptoms improved when away from school (school-related symptoms) was 22.7%, 20.4% and 39.2%, respectively, at baseline, and the prevalence increased during follow-up (P<0.001). At baseline, both indoor and outdoor SO₂ were found positively associated with prevalence of school-related symptoms. Indoor O₃ was shown to be positively associated with prevalence of skin symptoms. At follow-up, indoor PM₁₀ was found to be positively associated with new onset of skin, mucosal and general symptoms. CO₂ and RH were positively associated with new onset of mucosal, general and school-related symptoms. Outdoor SO₂ was positively associated with new onset of skin symptoms, while outdoor NO₂ was positively associated with new onset of skin, general and mucosal symptoms. Outdoor PM₁₀ was found to be positively associated with new onset of skin, general and mucosal symptoms as well as school-related symptoms. In conclusion, symptoms as described for SBS were commonly found in school children in Taiyuan City, China, and increased during the two-year follow-up period. Environmental pollution, including PM₁₀, SO₂ and NO₂, could increase the prevalence and incidence of SBS and decrease the remission rate. Moreover, parental asthma and allergy (heredity) and pollen or pet allergy (atopy) can be risk factors for SBS.     

Association between Air Pollutants and Asthma Emergency Room Visits and Hospital Admissions in Time Series Studies: A Systematic Review and Meta-Analysis

Background

Air pollution constitutes a significant stimulus of asthma exacerbations; however, the impacts of exposure to major air pollutants on asthma-related hospital admissions and emergency room visits (ERVs) have not been fully determined.

Objective

We sought to quantify the associations between short-term exposure to air pollutants [ozone (O₃), carbon monoxide (CO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and particulate matter ≤10μm (PM₁₀) and PM_2.5] and the asthma-related emergency room visits (ERV) and hospitalizations.

Methods

Systematic computerized searches without language limitation were performed. Pooled relative risks (RRs) and 95% confidence intervals (95%CIs) were estimated using the random-effect models. Sensitivity analyses and subgroup analyses were also performed.

Results

After screening of 246 studies, 87 were included in our analyses. Air pollutants were associated with significantly increased risks of asthma ERVs and hospitalizations [O₃: RR(95%CI), 1.009 (1.006, 1.011); I² = 87.8%, population-attributable fraction (PAF) (95%CI): 0.8 (0.6, 1.1); CO: RR(95%CI), 1.045 (1.029, 1.061); I² = 85.7%, PAF (95%CI): 4.3 (2.8, 5.7); NO₂: RR(95%CI), 1.018 (1.014, 1.022); I² = 87.6%, PAF (95%CI): 1.8 (1.4, 2.2); SO₂: RR(95%CI), 1.011 (1.007, 1.015); I² = 77.1%, PAF (95%CI): 1.1 (0.7, 1.5); PM₁₀: RR(95%CI), 1.010 (1.008, 1.013); I² = 69.1%, PAF (95%CI): 1.1 (0.8, 1.3); PM_2.5: RR(95%CI), 1.023 (1.015, 1.031); I² = 82.8%, PAF (95%CI): 2.3 (1.5, 3.1)]. Sensitivity analyses yielded compatible findings as compared with the overall analyses without publication bias. Stronger associations were found in hospitalized males, children and elderly patients in warm seasons with lag of 2 days or greater.

Conclusion

Short-term exposures to air pollutants account for increased risks of asthma-related ERVs and hospitalizations that constitute a considerable healthcare utilization and socioeconomic burden.     

Effects of air pollution and habitual exercise on the risk of death: a longitudinal cohort study

Background:Exercise may exacerbate the adverse health effects of air pollution by increasing the inhalation of air pollutants. We investigated the combined effects of long-term exposure to fine particle matter (PM_2.5) and habitual exercise on deaths from natural causes in Taiwan.Methods:We recruited 384 130 adults (aged ≥ 18 yr) with 842 394 medical examination records between 2001 and 2016, and followed all participants until May 31, 2019. We obtained vital data from the National Death Registry of Taiwan. We estimated PM_2.5 exposure using a satellite-based spatiotemporal model, and collected information on exercise habits using a standard self-administered questionnaire. We analyzed the data using a Cox regression model with time-dependent covariates.Results:A higher level of habitual exercise was associated with a lower risk of death from natural causes, compared with inactivity (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.80–0.88 for the moderate exercise group; HR 0.65, 95% CI 0.62–0.68 for the high exercise groups), whereas a higher PM_2.5 exposure was associated with a higher risk of death from natural causes compared with lower exposure (HR 1.02, 95% CI 0.98–1.07, and HR 1.15, 95% CI 1.10–1.20, for the moderate and high PM_2.5 exposure groups, respectively). Compared with inactive adults with high PM_2.5 exposure, adults with high levels of habitual exercise and low PM_2.5 exposure had a substantially lower risk of death from natural causes. We found a minor, but statistically significant, interaction effect between exercise and PM_2.5 exposure on risk of death (HR 1.03 95% CI 1.01–1.06). Subgroup analyses, stratified by PM_2.5 categories, suggested that moderate and high levels of exercise were associated with a lower risk of death in each PM_2.5 stratum, compared with inactivity.Interpretation:Increased levels of exercise and reduced PM_2.5 exposure are associated with a lower risk of death from natural causes. Habitual exercise can reduce risk regardless of the levels of PM_2.5 exposure. Our results suggest that exercise is a safe health improvement strategy, even for people residing in relatively polluted regions.

Air pollution and physical inactivity are both major public health challenges worldwide.¹ Air pollution was the fifth leading cause of disability related to health and accounted for 4.9 million deaths worldwide in 2017.² More than 91% of the global population lives in areas where air quality does not meet the World Health Organization (WHO) guidelines.³ In addition, physical inactivity was the fourth leading risk factor for death globally, accounting for 5.3 million deaths worldwide in 2012.⁴ The WHO has challenged its member states to reduce physical inactivity by 15% by 2030.⁵As people exercise, their ventilation rate increases, which increases the volume of air pollutants they inhale. This may exacerbate the adverse health effects of air pollutants. Thus, the risk–benefit relation between air pollution and exercise needs to be assessed to understand whether it is safe to exercise regularly in polluted regions. Indeed, some studies have shown that acute exposure to air pollution when exercising may override the benefits of exercise.^6,7 It is possible that the effects of long-term exposure to air pollution may be irreversible and cause a much larger disease burden than short-term exposure. Limited information exists on the combined effects of long-term exposure to air pollution and habitual exercise on human health, and findings have been inconsistent depending on health outcome. Three cohort studies have explored the relation between air pollution, physical activity and risk of death in Hong Kong,⁸ Denmark and the United States,⁹ with relatively small sample sizes.¹⁰ Therefore, we sought to investigate the combined effects of habitual exercise and long-term exposure to fine particle matter (PM_2.5) on the risk of death from natural causes (i.e., deaths not attributable to accident, suicide or homicide) using a longitudinal cohort of adults in Taiwan, where the annual PM_2.5 concentrations are 1.6 times higher than the WHO-recommended limit. We hypothesized that the beneficial effects of habitual exercise on risk of death may outweigh the risk of high levels of air pollutants inhaled during exercise.     

Air quality improvement and cognitive decline in community-dwelling older women in the United States: A longitudinal cohort study

BackgroundLate-life exposure to ambient air pollution is a modifiable risk factor for dementia, but epidemiological studies have shown inconsistent evidence for cognitive decline. Air quality (AQ) improvement has been associated with improved cardiopulmonary health and decreased mortality, but to the best of our knowledge, no studies have examined the association with cognitive function. We examined whether AQ improvement was associated with slower rate of cognitive decline in older women aged 74 to 92 years.Methods and findingsWe studied a cohort of 2,232 women residing in the 48 contiguous US states that were recruited from more than 40 study sites located in 24 states and Washington, DC from the Women’s Health Initiative (WHI) Memory Study (WHIMS)-Epidemiology of Cognitive Health Outcomes (WHIMS-ECHO) study. They were predominantly non-Hispanic White women and were dementia free at baseline in 2008 to 2012. Measures of annual (2008 to 2018) cognitive function included the modified Telephone Interview for Cognitive Status (TICSm) and the telephone-based California Verbal Learning Test (CVLT). We used regionalized universal kriging models to estimate annual concentrations (1996 to 2012) of fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) at residential locations. Estimates were aggregated to the 3-year average immediately preceding (recent exposure) and 10 years prior to (remote exposure) WHIMS-ECHO enrollment. Individual-level improved AQ was calculated as the reduction from remote to recent exposures. Linear mixed effect models were used to examine the associations between improved AQ and the rates of cognitive declines in TICSm and CVLT trajectories, adjusting for sociodemographic (age; geographic region; race/ethnicity; education; income; and employment), lifestyle (physical activity; smoking; and alcohol), and clinical characteristics (prior hormone use; hormone therapy assignment; depression; cardiovascular disease (CVD); hypercholesterolemia; hypertension; diabetes; and body mass index [BMI]). For both PM_2.5 and NO₂, AQ improved significantly over the 10 years before WHIMS-ECHO enrollment. During a median of 6.2 (interquartile range [IQR] = 5.0) years of follow-up, declines in both general cognitive status (β = −0.42/year, 95% CI: −0.44, −0.40) and episodic memory (β = −0.59/year, 95% CI: −0.64, −0.54) were observed. Greater AQ improvement was associated with slower decline in TICSm (β_{PM2.5improvement} = 0.026 per year for improved PM_2.5 by each IQR = 1.79 μg/m³ reduction, 95% CI: 0.001, 0.05; β_{NO2improvement} = 0.034 per year for improved NO₂ by each IQR = 3.92 parts per billion [ppb] reduction, 95% CI: 0.01, 0.06) and CVLT (β_{PM2.5 improvement} = 0.070 per year for improved PM_2.5 by each IQR = 1.79 μg/m³ reduction, 95% CI: 0.02, 0.12; β_{NO2improvement} = 0.060 per year for improved NO₂ by each IQR = 3.97 ppb reduction, 95% CI: 0.005, 0.12) after adjusting for covariates. The respective associations with TICSm and CVLT were equivalent to the slower decline rate found with 0.9 to 1.2 and1.4 to 1.6 years of younger age and did not significantly differ by age, region, education, Apolipoprotein E (ApoE) e4 genotypes, or cardiovascular risk factors. The main limitations of this study include measurement error in exposure estimates, potential unmeasured confounding, and limited generalizability.ConclusionsIn this study, we found that greater improvement in long-term AQ in late life was associated with slower cognitive declines in older women. This novel observation strengthens the epidemiologic evidence of an association between air pollution and cognitive aging.

Diana Younan and colleagues investigate whether air quality improvement is associated with rate of cognitive decline in community-dwelling older women in the United States.