Acute Effects of Ambient Air Pollution on Asthma Emergency Department Visits in Ten U.S. States

Long-term exposure to ambient ozone and adult-onset asthma: A prospective cohort study

BACKGROUND

The association between long-term exposure to ozone (O3) and adult-onset asthma (AOA) remains inconclusive, and analysis of causality is lacking.

OBJECTIVES

To examine the causal association between long-term O3 exposure and AOA.

METHODS

A prospective cohort study of 362,098 participants was conducted using the UK Biobank study. Incident cases of AOA were identified using health administrative data of the National Health Services. O3 exposure at participants' residential addresses was estimated by a spatio-temporal model. Instrumental variable (IV) modelling was used to analyze the causal association between O3 exposure and AOA, by incorporating wind speed and planetary boundary layer height as IVs into time-dependent Cox model. Negative control outcome (accidental injury) was also used to additionally evaluate unmeasured confounding.

RESULTS

During a mean follow-up of 11.38 years, a total of 10,973 incident AOA cases were identified. A U-shaped concentration-response relationship was observed between O3 exposure and AOA in the traditional Cox models with HR of 0.916 (95% CI: 0.888, 0.945) for O3 at low levels (<38.17 ppb), and 1.204 (95% CI: 1.168, 1.242) for O3 at high levels (≥38.17 ppb). However, in the IV analysis we only found a statistically significant association between high-level O3 exposure and AOA risk, but not for low-level O3 exposure. No significant associations between O3 exposure and accidental injury were observed.

CONCLUSION

Our findings suggest a potential causal relationship between long-term exposure to high-level ambient O3 and increased risks of AOA.

The impact of PM2.5 on lung function and chronic respiratory diseases: insights from genetic evidence

BACKGROUND

PM2.5 has been associated with various adverse health effects, particularly affecting lung function and chronic respiratory diseases. However, the genetic causality relationship between PM2.5 exposure and lung function as well as chronic respiratory diseases remains poorly understood.

METHOD

We conducted a two-sample Mendelian randomization analysis to investigate the causal impact of PM2.5 on lung function and chronic respiratory diseases. Instrumental variables were carefully selected, with significance thresholds (P < 5 × 10- 8), and linkage disequilibrium with an r2 value below 0.001. Additionally, SNPs with an F-statistic exceeding 10 were included to mitigate potential bias stemming from weak instrumental variables. The primary analytical approach employed the Inverse Variance Weighted method, supplemented by the Weighted Median, MR-Egger, Simple Model, and Weighted Model. Furthermore, pleiotropy and heterogeneity were evaluated through the MR-Egger intercept test and Cochrane's Q test, with a sensitivity analysis conducted using the leave-one-out method.

RESULTS

Eight SNPs significantly associated with PM2.5 exposure were identified as Instrumental variables. Mendelian randomization analysis revealed a significant causal association between PM2.5 exposure and lung function (FEV), with an OR of 0.7284 (95% CI: 0.5799-0.9150). Similarly, PM2.5 exposure demonstrated a substantial causal effect on asthma, with an OR of 1.5280 (95% CI: 1.0470-2.2299). However, no causal association was observed between PM2.5 exposure and chronic obstructive pulmonary disease, with an OR of 1.5176 (95% CI: 0.8294-2.7768).

CONCLUSION

These findings emphasize the necessity for continued research efforts in environmental health to develop effective strategies for the prevention and management of chronic respiratory diseases.

Environmental Injustice Is Associated With Poorer Asthma Outcomes in School-Age Children With Asthma in Metropolitan Atlanta, Georgia

BACKGROUND

Environmental justice mandates that no person suffers disproportionately from environmental exposures. The Environmental Justice Index (EJI) provides an estimate of the environmental burden for each census tract but has not yet been used in asthma populations.

OBJECTIVE

We hypothesized that children from census tracts with high environmental injustice determined by the EJI would have a greater burden of asthma exacerbations, poorer asthma control, and poorer lung function over 12 months.

METHODS

Children aged 6 to 18 years with asthma (N = 575) from metropolitan Atlanta, Georgia, completed a baseline research visit. Participant addresses were geocoded to obtain the EJI Social-Environmental Ranking for each participant's census tract, which was divided into tertiles. Medical records were reviewed for 12 months for asthma exacerbations. A subset of participants completed a second research visit involving spirometry and questionnaires.

RESULTS

Census tracts with the greatest environmental injustice had more racial and ethnic minorities, lower socioeconomic status, more hazardous exposures (particularly to airborne pollutants), and greater proximity to railroads and heavily trafficked roadways. Children with asthma residing in high injustice census tracts had a longer duration of asthma, greater historical asthma-related health care utilization, poorer asthma symptom control and quality of life, and more impaired lung function. By 12 months, children from high injustice census tracts also had more asthma exacerbations with a shorter time to exacerbation and persistently more symptoms, poorer asthma control, and reduced lung function.

CONCLUSIONS

Disparities in environmental justice are present in metropolitan Atlanta that may contribute to asthma outcomes in children. These findings require an additional study and action to improve health equity.

Short-term exposures to PM2.5, PM2.5 chemical components, and antenatal depression: Exploring the mediating roles of gut microbiota and fecal short-chain fatty acids

BACKGROUND

PM2.5 and its chemical components increase health risks and are associated with depression and gut microbiota. However, there is still limited evidence on whether gut microbiota and short-chain fatty acids (SCFAs) mediate the association between PM2.5, PM2.5 chemical components, and antenatal depression. The purpose of this study was to investigate the mediating role of maternal gut microbiota in correlations between short-term exposure to PM2.5, short-term exposure to PM2.5 chemical components, and antenatal depression.

METHODS

Demographic information and stool samples were collected from 75 pregnant women in their third trimester. Their exposure to PM2.5 and PM2.5 chemical components was measured. Participants were divided into the non-antenatal depression group or the antenatal depression group according to the cut-off of 10 points on the Edinburgh Postnatal Depression Scale (EPDS). The gut microbiota were analyzed using the 16 S rRNA-V3/V4 gene sequence, and the concentration of PM2.5 and its chemical components was calculated using the Tracking Air Pollution in China (TAP) database. Gas chromatography-mass spectrometry was used to analyze SCFAs in stool samples. In order to assess the mediating effects of gut microbiota and SCFAs, mediation models were utilized.

RESULTS

There were significant differences between gut microbial composition and SCFAs concentrations between the non-antenatal depression group and the antenatal depression group. PM2.5 and its chemical components were positively associated with EPDS scores and negatively associated with genera Enterococcus and Enterobacter. Genera Candidatus_Soleaferrea (β = -7.21, 95%CI -11.00 to -3.43, q = 0.01) and Enterococcus (β = -2.37, 95%CI -3.87 to -0.87, q = 0.02) were negatively associated with EPDS scores, indicating their potential protective effects against antenatal depression. There was no significant association between SCFAs and EPDS scores. The mediating role of Enterococcus between different lagged periods of PM2.5, PM2.5 chemical component exposure, and antenatal depression was revealed. For instance, Enterococcus explained 29.23% (95%CI 2.16-87.13%, p = 0.04) of associations between PM2.5 exposure level at the day of sampling (lag 0) and EPDS scores.

CONCLUSION

Our study highlights that Enterococcus may mediate the associations between PM2.5, PM2.5 chemical components, and antenatal depression. The mediating mechanism through which the gut microbiota influences PM2.5-induced depression in pregnant women still needs to be further studied.

The frequency of asthma and its related factors: results of the enrolment phase of Tabari cohort study

INTRODUCTION

A large portion of the world's population has asthma. This study aimed to ascertain asthma prevalence and related factors in the Tabari cohort study (TCS).

METHODS

The TCS included 10,255 35-70-year-olds from urban and mountainous Sari (northern Iran) between June 2015 and November 2017. Education, occupation, domicile, socioeconomic position, history of psychiatric disorders, smoking (including hookah smoking), opium usage, and daily physical activity level were determined.

RESULTS

The final analysis included 9939 individuals. The asthma rate was 7.4%. Multiple factors increased asthma risk, according to statistical analysis. These factors included being female (OR, 1.337; 95% CI, 1.142-1.565), retired (OR, 1.553; 95% CI, 1.205-2.002), living in the city (OR, 1.268; 95% CI, 1.083-1.484), using opioids (OR, 1.689; 95% CI, 1.299-2.197), having lower socioeconomic status (SES) (OR, 0.723; 95% CI, 0.579-0.903), history of psychiatric disorders (OR, 2.313; 95% CI, 1.826-2.930), and aged 60-70 (OR, 2.325; 95% CI, 1.765-3.064), and BMI above 30 kg/m2 (OR, 1.499; 95% CI, 1.220-1.841). Several factors increased asthma probability in multivariate regression analysis. These factors include being female (OR = 1.389, p = 0.015), ages between 60 and 70 (OR = 2.034, p < 0.001), using opioids (OR = 1.940, p < 0.001), lower SES (OR = 0.738, p = 0.012), history of psychiatric disorders (OR = 2.035, p < 0.001), BMI above 30 kg/m2 (OR = 1.518, p < 0.001), and being a smoker (OR = 1.337, p = 0.056).

CONCLUSION

This study has identified that the prevalence of asthma in the Tabari cohort group is high. In addition, it was demonstrated that various factors are related to asthma.

Warm season ambient ozone and children's health in the USA

BACKGROUND

Over 120 million people in the USA live in areas with unsafe ozone (O3) levels. Studies among adults have linked exposure to worse lung function and higher risk of asthma and chronic obstructive pulmonary disease (COPD). However, few studies have examined the effects of O3 in children, and existing studies are limited in terms of their geographic scope or outcomes considered.

METHODS

We leveraged a dataset of encounters at 42 US children's hospitals from 2004-2015. We used a one-stage case-crossover design to quantify the association between daily maximum 8-hour O3 in the county in which the hospital is located and risk of emergency department (ED) visits for any cause and for respiratory disorders, asthma, respiratory infections, allergies and ear disorders.

RESULTS

Approximately 28 million visits were available during this period. Per 10 ppb increase, warm-season (May through September) O3 levels over the past three days were associated with higher risk of ED visits for all causes (risk ratio [RR]: 0.3% [95% confidence interval (CI): 0.2%, 0.4%]), allergies (4.1% [2.5%, 5.7%]), ear disorders (0.8% [0.3%, 1.3%]) and asthma (1.3% [0.8%, 1.9%]). When restricting to levels below the current regulatory standard (70 ppb), O3 was still associated with risk of ED visits for all-cause, allergies, ear disorders and asthma. Stratified analyses suggest that the risk of O3-related all-cause ED visits may be higher in older children.

CONCLUSIONS

Results from this national study extend prior research on the impacts of daily O3 on children's health and reinforce the presence of important adverse health impacts even at levels below the current regulatory standard in the USA.

Respiratory Health Effects of Air Pollutants

Air pollution is a risk factor for asthma and respiratory infection. Avoidance of air pollution is the best approach to mitigating the impacts of pollution. Personal preventive strategies are possible, but policy interventions are the most effective ways to prevent pollution and its effect on asthma and respiratory infection.

The impact of air pollution on asthma: clinical outcomes, current epidemiology, and health disparities

INTRODUCTION

Air pollution has been shown to have a significant impact on morbidity and mortality of respiratory illnesses including asthma.

AREAS COVERED

Outdoor air pollution consists of a mixture of individual pollutants including vehicle traffic and industrial pollution. Studies have implicated an array of individual components of air pollution, with PM2.5, NO2, SO2, and ozone being the most classically described, and newer literature implicating other pollutants such as black carbon and volatile organic compounds. Epidemiological and cohort studies have described incidence and prevalence of pollution-related asthma and investigated both acute and chronic air pollution exposure as they relate to asthma outcomes. There is an increasing body of literature tying disparities in pollution exposure to clinical outcomes. In this narrative review, we assessed the published research investigating the association of pollution with asthma outcomes, focusing on the adult population and health care disparities.

EXPERT OPINION

Pollution has multiple deleterious effects on respiratory health but there is a lack of data on individualized pollution monitoring, making it difficult to establish a temporal relationship between exposure and symptoms, thereby limiting our understanding of safe exposure levels. Future research should focus on more personalized monitoring and treatment plans for mitigating exposure.