The association between high particulate matter pollution and daily cause-specific hospital admissions: a time-series study in Yichang, China

Effects of ambient air pollution on cause-specific hospitalizations in Wuhan during 2017-2019

BACKGROUND

Few studies have focused on the associations between air pollutants and multiple organ system diseases in the entire hospitalized population. The present study aims to explore the short-term effects of six routinely monitored air pollutants on the broad causes of hospital admissions and estimate the resulting hospital admission burdens.

METHODS

Daily hospital admission records from 2017 to 2019 were obtained from the Wuhan Information center of Health and Family Planning. Generalized additive models (GAMs) were employed to evaluate the effects of air pollutants on the percent increase in the cause-specific daily number of hospital admissions. Increased hospital admission numbers, days, and expenses were also estimated.

RESULTS

A total of 2636,026 hospital admissions were identified. We found that both PM_2.5 and PM₁₀ increased the risk of hospital admissions for most disease categories. Short-term exposure to PM_2.5 was positively associated with hospitalizations of several rarely studied disease categories, such as diseases of the eye and adnexa (2.83%, 95%CI: 0.96-4.73%, P < 0.01) and diseases of the musculoskeletal system and connective tissue (2.17%, 95% CI: 0.88-3.47%, P < 0.001). NO₂ was observed to have a robust effect on diseases of the respiratory system (1.36%, 95%CI: 0.74-1.98%, P < 0.001). CO was significantly associated with hospital admissions for six disease categories. Furthermore, each 10-μg/m³ increase in PM_2.5 was associated with an annual increase of 13,444 hospital admissions (95% CI: 6239-20,649), 124,344 admission days (95% CI: 57,705-190,983), and 166-million-yuan admission expenses (95% CI: 77-255).

CONCLUSION

Our study suggested that particulate matter (PM) had a short-term effect on hospital admissions of most major disease categories and resulted in a considerable hospital admission burden. In addition, the health effects of NO₂ and CO emissions require more attention in megacities.

Associations between short-term PM2.5 exposure and daily hospital admissions for circulatory system diseases in Ganzhou, China: A time series study

Objective

Previous epidemiological studies have shown that both long-term and short-term exposure to fine particulate matters (PM2.5) were associated with the morbidity and mortality of circulatory system diseases (CSD). However, the impact of PM2.5 on CSD remains inconclusive. This study aimed to investigate the associations between PM2.5 and circulatory system diseases in Ganzhou.

Methods

We conducted this time series study to explore the association between ambient PM2.5 exposure and daily hospital admissions for CSD from 2016 to 2020 in Ganzhou by using generalized additive models (GAMs). Stratified analyses were also performed by gender, age, and season.

Results

Based on 201,799 hospitalized cases, significant and positive associations were found between short-term PM2.5 exposure and hospital admissions for CSD, including total CSD, hypertension, coronary heart disease (CHD), cerebrovascular disease (CEVD), heart failure (HF), and arrhythmia. Each 10 μg/m3 increase in PM2.5 concentrations was associated with a 2.588% (95% confidence interval [CI], 1.161%–4.035%), 2.773% (95% CI, 1.246%–4.324%), 2.865% (95% CI, 0.786%–4.893%), 1.691% (95% CI, 0.239%–3.165%), 4.173% (95% CI, 1.988%–6.404%) and 1.496% (95% CI, 0.030%–2.983%) increment in hospitalizations for total CSD, hypertension, CHD, CEVD, HF, and arrhythmia, respectively. As PM2.5 concentrations rise, the hospitalizations for arrhythmia showed a slow upward trend, while other CSD increased sharply at high PM2.5 levels. In subgroup analyses, the impacts of PM2.5 on hospitalizations for CSD were not materially changed, although the females had higher risks of hypertension, HF, and arrhythmia. The relationships between PM2.5 exposure and hospitalizations for CSD were more significant among individuals aged ≤65 years, except for arrhythmia. PM2.5 had stronger effects on total CSD, hypertension, CEVD, HF, and arrhythmia during cold seasons.

Conclusion

PM2.5 exposure was positively associated with daily hospital admissions for CSD, which might provide informative insight on adverse effects of PM2.5.

Association between air pollution exposure and coronary heart disease hospitalization in a humid sub-tropical region of China: A time-series study

Objective

Emerging evidence has highlighted the possible links of environmental pollution with several cardiovascular diseases (CVDs). The current study aimed to explore the impact of short-term air pollution exposure on CHD hospitalization in Hefei.

Methods

Data about the daily number of CHD admissions (from 2014 to 2021) were retrieved from the First Affiliated Hospital of Anhui Medical University. Air pollutants and meteorological data were obtained from the China Environmental Monitoring Station and the China Meteorological Data Service Center, respectively. The correlation between air pollution and CHD hospitalization was assessed using distributed lag non-linear model (DLNM) and Poisson generalized linear regression.

Results

In the single-pollutant model, NO₂, O₃, and CO strongly correlated with CHD hospitalization rate. Specifically, exposure to NO₂ (lag0, relative risk [RR]: 1.013, 95%CI: 1.002-1.024, per 10 μg/m³ increase) and CO (lag13, RR: 1.035, 95%CI: 1.001-1.071, per 1 μg/m³ increase) revealed a positive correlation with an increased rate of CHD hospitalization. Interestingly, O₃ had a protective association with hospitalization of CHD (lag0, RR: 0.993, 95%CI: 0.988-0.999, per 10 μg/m³ increase). Similar results, to those of the single-pollutant model, were revealed following verification using two-pollutant models. Subgroup analyses indicated that young people, women, and people in hot seasons were more susceptible to NO₂ exposure, while the elderly, women, and people in cold seasons were more susceptible to O₃. Furthermore, the elderly were more susceptible to CO exposure.

Conclusion

Overall, exposure to NO₂ and CO increases the rate of CHD hospitalization, but exposure to O₃ shows a protective association with the rate of CHD hospitalization. Therefore, early preventive measures against air pollutants should be applied to protect vulnerable patients with CHD.

A Time Series Study for Effects of PM10 on Coronary Heart Disease in Ganzhou, China

Objective: To investigate the effect of PM10 exposure in low concentration areas on the daily hospitalized patients with coronary heart disease. Methods: Daily air quality monitoring data, meteorological monitoring data and daily hospitalization data of coronary heart disease during 2019−2021 in Ganzhou, China were collected. Generalized additive model and distributed lag nonlinear model were used to evaluate the association between environmental PM10 and daily hospital visits for coronary heart disease. Stratified by sex and age to see their potential impact on this association. Results: PM10 exposure was correlated with an increased risk of hospitalization in coronary heart disease patients. Single-pollutant model analysis shows that at the day of lag1, for every 10 µg/m3 increase in PM10, the risk of coronary heart disease hospitalization increased by 1.69% (95%CI 0.39~3.00%); Subgroup analysis showed that females and older adults (>65 years) were more sensitive to PM10 exposure. In addition, in the dual-pollutant model, by adjusting other pollutants (including SO2, CO and O3), it was found that the relationship between PM10 exposure and coronary heart disease hospitalization was robust. And with changing the model’s degree of freedom was still robust. Conclusion: Short-term exposure to low concentrations of PM10 is associated with hospitalization for coronary heart disease. These results are important for local environmental public health policy development, so as to protect vulnerable populations.

Ambient Air Quality and Emergency Hospital Admissions in Singapore: A Time-Series Analysis

Air pollution exposure may increase the demand for emergency healthcare services, particularly in South-East Asia, where the burden of air-pollution-related health impacts is high. This article aims to investigate the association between air quality and emergency hospital admissions in Singapore. Quasi-Poisson regression was applied with a distributed lag non-linear model (DLNM) to assess the short-term associations between air quality variations and all-cause, emergency admissions from a major hospital in Singapore, between 2009 and 2017. Higher concentrations of SO₂, PM_2.5, PM₁₀, NO₂, and CO were positively associated with an increased risk of (i) all-cause, (ii) cardiovascular-related, and (iii) respiratory-related emergency admissions over 7 days. O₃ concentration increases were associated with a non-linear decrease in emergency admissions. Females experienced a higher risk of emergency admissions associated with PM_2.5, PM₁₀, and CO exposure, and a lower risk of admissions with NO₂ exposure, compared to males. The older adults (≥65 years) experienced a higher risk of emergency admissions associated with SO₂ and O₃ exposure compared to the non-elderly group. We found significant positive associations between respiratory disease- and cardiovascular disease-related emergency hospital admissions and ambient SO₂, PM_2.5, PM₁₀, NO₂, and CO concentrations. Age and gender were identified as effect modifiers of all-cause admissions.

Long-term PM2.5 exposure in association with chronic respiratory diseases morbidity: A cohort study in Northern China

Several literatures have examined the risk of chronic respiratory diseases in association with short-term ambient PM2.5 exposure in China. However, little evidence has examined the chronic impacts of PM2.5 exposure on morbidity of chronic respiratory diseases in cohorts from high pollution countries. Our study aims to investigate the associations. Based on a retrospective cohort among adults in northern China, a Cox regression model with time-varying PM2.5 exposure and a concentration-response (C-R) curve model were performed to access the relationships between incidence of chronic respiratory diseases and long-term PM2.5 exposure during a mean follow-up time of 9.8 years. Individual annual average PM2.5 estimates were obtained from a satellite-based model with high resolution. The incident date of a chronic respiratory disease was identified according to self-reported physician diagnosis time and/or intake of medication for treatment. Among 38,047 urban subjects analyzed in all-cause chronic respiratory disease cohort, 482 developed new cases. In CB (38,369), asthma (38,783), and COPD (38,921) cohorts, the onsets were 276, 89, and 14, respectively. After multivariable adjustment, hazard ratio and 95% confidence interval for morbidity of all-cause chronic respiratory disease, CB, asthma, and COPD were 1.15 (1.01, 1.31), 1.20 (1.00, 1.42), 0.76 (0.55, 1.04), and 0.66 (0.29, 1.47) with each 10 μg/m3 increment in PM2.5, respectively. Stronger effect estimates were suggested in alcohol drinkers across stratified analyses. Additionally, the shape of C-R curve showed an increasing linear relationship before 75.00 μg/m3 concentrations of PM2.5 for new-onset all-cause chronic respiratory disease, and leveled off at higher levels. These findings indicated that long-term exposure to high-level PM2.5 increased the risks of incident chronic respiratory diseases in China. Further evidence of C-R curves is warranted to clarify the associations of adverse chronic respiratory outcomes involving air pollution.

Effect modification by sex for associations of fine particulate matter (PM2.5) with cardiovascular mortality, hospitalization, and emergency room visits: systematic review and meta-analysis

Particulate matter with aerodynamic diameter no larger than 2.5 μm (PM2.5) has been linked to cardiovascular diseases (CVDs) but evidence for vulnerability by sex remains unclear. We performed systematic review and meta-analysis to synthesize the state of scientific evidence on whether cardiovascular risks from PM2.5 differ for men compared to women. The databases Pubmed, Scopus, Embase, and GreenFILE were searched for studies published Jan. 1995 to Feb. 2020. Observational studies conducting subgroup analysis by sex for impacts of short-term or long-term exposure to PM2.5 on target CVDs were included. Data were independently extracted in duplicate and pooled with random-effects meta-regression. Risk ratios (RRs) for long-term exposure and percent changes in outcomes for short-term exposure were calculated per 10 μg/m3 PM2.5 increase. Quality of evidence of risk differences by sex was rated following Grading of Recommendations Assessment, Development and Evaluation (GRADE). A total of 12,502 articles were screened, with 61 meeting inclusion criteria. An additional 32 studies were added from citation chaining. RRs of all CVD mortality for long-term PM2.5 for men and women were the same (1.14; 95% CI: 1.09, 1.22) indicating no statistically different risks. Men and women did not have statistically different risks of daily CVD mortality, hospitalizations from all CVD, ischemic heart disease, cardiac arrest, acute myocardial infarction, and heart failure from short-term PM2.5 exposure (difference in % change in risk per 10 μg/m3 PM2.5: 0.04 (95% CI, -0.42 to 0.51); -0.05 (-0.47 to 0.38); 0.17 (-0.90, 1.24); 1.42 (-1.06, 3.97); 1.33 (-0.05, 2.73); and -0.48 (-1.94, 1.01), respectively). Analysis using GRADE found low or very low quality of evidence for sex differences for PM2.5-CVD risks. In conclusion, this meta-analysis and quality of evidence assessment of current observational studies found very limited evidence of the effect modification by sex for effects of PM2.5 on CVD outcomes in adults, which can inform clinical approaches and policies.

Research on prediction of daily admissions of respiratory diseases with comorbid diabetes in Beijing based on long short-term memory recurrent neural network

To compare the performance of generalized additive model (GAM) and long short-term memory recurrent neural network (LSTM-RNN) on the prediction of daily admissions of respiratory diseases with comorbid diabetes. Daily data on air pollutants, meteorological factors and hospital admissions for respiratory diseases from Jan 1st, 2014 to Dec 31st, 2019 in Beijing were collected. LSTM-RNN was used to predict the daily admissions of respiratory diseases with comorbid diabetes, and the results were compared with those of GAM. The evaluation indexes were calculated by five-fold cross validation. Compared with the GAM, the prediction errors of LSTM-RNN were significantly lower [root mean squared error (RMSE): 21.21±3.30 vs. 46.13±7.60, <0.01; mean absolute error (MAE): 14.64±1.99 vs. 36.08±6.20, <0.01], and the value was significantly higher (0.79±0.06 vs. 0.57±0.12, <0.01). In gender stratification, RMSE, MAE and values of LSTM-RNN were better than those of GAM in predicting female admission (all <0.05), but there were no significant difference in predicting male admission between two models (all >0.05). In seasonal stratification, RMSE and MAE of LSTM-RNN were lower than those of GAM in predicting warm season admission (all <0.05), but there was no significant difference in value (>0.05). There were no significant difference in RMSE, MAE and between the two models in predicting cold season admission (all >0.05). In the stratification of functional areas, the RMSE, MAE and values of LSTM-RNN were better than those of GAM in predicting core area admission (all <0.05). has lower prediction errors and better fitting than the GAM, which can provide scientific basis for precise allocation of medical resources in polluted weather in advance.

Influence of PM1 exposure on total and cause-specific respiratory diseases: a systematic review and meta-analysis

An increasing number of studies examined the potential effects of PM1 (submicronic particulate matter with an aerodynamic diameter ≤ 1 μm) on the risk of respiratory diseases; however, the results have been inconclusive. This study aimed to determine the overall association between PM1 with total and cause-specific respiratory diseases. A systematic review and meta-analysis was conducted with 68 related articles retrieved, and six articles met the full inclusion criteria for the final analysis. For a 10 μg/m3 increase in PM1, the pooled odds ratio (OR) was 1.05 (95% CI 0.98-1.12) for total respiratory diseases, 1.25 (95% CI 1.00-1.56) for asthma, and 1.07 (95% CI 1.04-1.10) for pneumonia with the I2 value of 87%, 70%, and 0%, respectively. Subgroup analyses showed that long-term exposure to PM1 was associated with increased risk of asthma (OR 1.47, 95% CI 1.33-1.63) with an I2 value of 0%, while short-term exposure to PM1 was not associated with asthma (OR 1.07, 95% CI 0.89-1.27) with the I2 value of 0%. Egger's test showed that publication bias existed (P = 0.041); however, the funnel plot was symmetrical with the inclusion of the moderator. In conclusion, elevated levels of PM1 may increase morbidity in total and cause-specific respiratory diseases in the population.

Effects of particulate matter on hospital admissions for respiratory diseases: an ecological study based on 12.5 years of time series data in Shanghai

BACKGROUND

Previous epidemiological studies on the association between short-term exposure to particulate matter (PM) with hospital admission in major cities in China were limited to shorter study periods or a single hospital. The aim of this ecological study based on a 12.5-year time series was to investigate the association of short-term exposure to PM with aerodynamic diameter ≤ 2.5 μm (PM_2.5) and aerodynamic diameter ≤ 10 μm (PM₁₀) with hospital admissions for respiratory diseases.

METHODS

Daily hospital admissions data were from the Shanghai Medical Insurance System for the period January 1, 2008 to July 31, 2020. We estimated the percentage change with its 95% confidence interval (CI) for each 10 μg/m³ increase in the level of PM_2.5 and PM₁₀ after adjustment for calendar time, day of the week, public holidays, and meteorological factors applying a generalized additive model with a quasi-Poisson distribution.

RESULTS

There were 1,960,361 hospital admissions for respiratory diseases in Shanghai during the study period. A 10 μg/m³ increase in the level of each class of PM was associated with increased total respiratory diseases when the lag time was 0 day (PM_2.5: 0.755%; 95% CI: 0.422, 1.089%; PM₁₀: 0.250%; 95% CI: 0.042, 0.459%). The PM_2.5 and PM₁₀ levels also had positive associations with admissions for COPD, asthma, and pneumonia. Stratified analyses demonstrated stronger effects in patients more than 45 years old and during the cold season. Total respiratory diseases increased linearly with PM concentration from 0 to 100 μg/m³, and increased more slowly at higher PM concentrations.

CONCLUSIONS

This time-series study suggests that short-term exposure to PM increased the risk for hospital admission for respiratory diseases, even at low concentrations. These findings suggest that reducing atmospheric PM concentrations may reduce hospital admissions for respiratory diseases.

Assessing short-term impacts of PM2.5 constituents on cardiorespiratory hospitalizations: Multi-city evidence from China

Apart from concentrations of particulate mass, PM_2.5-associated effects on health may largely depend on its chemical components. However, little is known regarding the underlying effects of specific PM_2.5 constituents. The study included nearly 1 million hospital admissions from five Chinese cities during 2015-2017. Based on the modified Community Multiscale Air Quality model, our study simulated daily concentrations of PM_2.5 and five main components. We used a time-stratified case-crossover design with conditional logistic regression models to estimate short-term effects of PM_2.5 constituents on cause-specific hospital admissions. Per interquartile range increase in exposure to PM_2.5, elemental carbon, organic carbon, nitrate, sulfate and ammonium at lag 04-day was related to an excess risk (ER%) for non-accidental admissions of 1.6% [95% confidence interval: 1.1-2.0], 1.9% [1.3-2.4], 1.0% [0.5-1.6], 1.2% [0.4-2.0], 1.2% [0.9-1.5] and 1.4% [0.9-1.9], respectively. Great heterogeneities of constituents-admission associations existed in diverse causes and constituents. This study provided multi-center high-quality evidence that hospital admissions, particularly those for ischemic heart disease (ER% ranging from 2.3 to 5.4% at lag 04-day) and pneumonia (1.9-5.1% at lag 4-day), could be triggered by short-term exposures to ambient PM_2.5 constituents. Relatively stronger constituents-admission associations were found among females for respiratory causes and the elderly for cardiovascular causes.

Mitochondria damage in ambient particulate matter induced cardiotoxicity: Roles of PPAR alpha/PGC-1 alpha signaling

Particulate matter (PM) had been associated with cardiotoxicity, while the mechanism of toxicity has yet to be elucidated, with mitochondria dysfunction as a potential candidate. To investigate the potential cardiotoxic effects of ambient PM exposure and assess the damage to cardiac mitochondria, C57/B6 mice were exposed to filtered air or real ambient PM for three or six weeks. Furthermore, to reveal the role of peroxisome proliferators-activated receptor alpha (PPAR alpha) in PM exposure induced cardiotoxicity/mitochondria damage, animals were also co-treated with PPAR alpha agonist WY 14,643 or PPAR alpha antagonist GW 6471. Cardiotoxicity was assessed with echocardiography and histopathology, while mitochondria damage was evaluated with mitochondria membrane potential measurement and transmission electron microscopy. Potential impacts of PM exposure to PPAR alpha signaling were detected with co-immunoprecipitation and western blotting. The results indicated that exposure to ambient PM exposure induced cardiotoxicity in C57/B6 mice, including altered cardiac functional parameters and morphology. Cardiac mitochondria damage is detected, in the form of compromised mitochondria membrane potential and morphology. Molecular investigations revealed disruption of PPAR alpha interaction with peroxisome proliferator-activated receptor gamma coactivator-1A (PGC-1a) as well as altered expression levels of PPAR alpha downstream genes. Co-treatment with WY 14,643 alleviated the observed toxicities, while co-treatment with GW 6471 had mixed results, exaggerating most cardiotoxicity and mitochondrial damage endpoints but alleviating some cardiac functional parameters. Interestingly, WY 14,643 and GW 6471 co-treatment seemed to exhibit similar regulative effects towards PPAR alpha signaling in animals exposed to PM. In conclusion, ambient PM exposure indeed induced cardiotoxicity in C57/B6 mice, in which cardiac mitochondria damage and disrupted PPAR alpha signaling are contributors.

The association between fine particulate matter and acute lower respiratory infections in Yancheng City, China

Due to the rapid economic development and acceleration of industrialization, most cities in China are experiencing severe air pollution. Exposure to fine particulate matter (PM_2.5) has been associated with acute lower respiratory tract infection (ALRI). To estimate associations between short-term exposure to PM_2.5 and ALRI hospitalization in Yancheng City, China. This was a 6-year time-series study from 2014 to 2019. Data on hospitalization were collected from four high-ranked general hospitals, including for community-acquired pneumonia (CAP), acute exacerbation of chronic bronchitis (AECB), acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and acute exacerbation of bronchiectasis (AEB), and the sum was termed total ALRIs. We obtained pollutant exposure data from five fixed monitoring stations. The association between PM_2.5 and ALRI hospitalization was estimated using the generalized linear model with quasi-Poisson regression. Two-pollutant models were applied to test the robustness of the observed correlations. Subgroup analyses included sex, age, and season. During the study period, a total of 43,283 cases of total ALRIs were recorded. The average annual mean PM_2.5 concentration was 45.4 ± 32.3 μg/m³. A 10-μg/m³ increase in PM_2.5 concentration (lag 0) was significantly associated with increases in hospitalizations for total ALRIs (at 0.73%; 95% CI: 0.40%, 1.06%), in CAP (at 0.80%; 95% CI: 0.02%, 1.57%), in for AECOPD (1.08%; 95% CI: 0.38%, 1.78%), and AECB (0.67%; 95% CI: 0.23%, 1.11%). The estimated effects for total ALRIs and AECB were relatively robust with adjustment for other air pollutants. Associations between PM_2.5 and total ALRIs were stronger in females, in the elderly, and in the cold season. PM_2.5 exposure was significantly associated with ALRI morbidity, and females and older people were more susceptible to PM_2.5 air pollution, especially in the cold season.

Associations between Dust Exposure and Hospitalizations in El Paso, Texas, USA

The Southwestern USA has been identified as one of the most persistent dust-producing regions of North America, where exposure to inhalable particulate matter (PM10) originating from desertic landscape during dust events/dust exposures (DEs) can reach hazardous levels. El Paso, Texas’s ambient air has reached hazardous levels of PM10 from dust with near zero visibility due to these natural events originating in the surrounding Chihuahuan Desert. The aim of this study was to investigate whether dust exposures in El Paso (generally acute, short-term exposures from nearby source areas) are associated with significant increases in hospitalizations on the day of the exposure and up to seven days afterwards. Using a Poisson regression, it was found that the relative risks of hospitalizations due to a variety of conditions were associated with dust exposures (through increases of 100 μg/m3 maximum hourly PM10 and/or increases of 4.5 m/s maximum hourly wind speed) in El Paso County, Texas between 2010 and 2014. Valley fever, coronary atherosclerosis, genitourinary diseases, neurodegenerative diseases, injury and poisoning, circulatory system conditions, respiratory system diseases, births, septicemia, Associated Diseases (the aggregation of hospital admissions for all causes, each associated with at least 5% of hospitalizations), and all ICD-9 admissions were significantly positively associated with dust exposures, indicated from higher to lower significant risk, at different lag periods after exposure. These findings, showing that an association does exist between dust exposures and hospitalizations, have important implications for residents of the world’s dryland cities.

Role of atmospheric particulate matter exposure in COVID-19 and other health risks in human: A review

Due to intense industrialization and urbanization, air pollution has become a serious global concern as a hazard to human health. Epidemiological studies found that exposure to atmospheric particulate matter (PM) causes severe health problems in human and significant damage to the physiological systems. In recent days, PM exposure could be related as a carrier for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus transmission and Coronavirus disease 2019 (COVID-19) infection. Hence, it is important to understand the adverse effects of PM in human health. This review aims to provide insights on the detrimental effects of PM in various human health problems including respiratory, circulatory, nervous, and immune system along with their possible toxicity mechanisms. Overall, this review highlights the potential relationship of PM with several life-limiting human diseases and their significance for better management strategies.

Sepsis-related hospital admissions and ambient air pollution: a time series analysis in 6 Chinese cities

Background

Some prevalent but rarely studied causes of hospital admissions, such as sepsis is still unknown whether affected by air pollution.

Methods

We used time-series regression within generalized additive models to estimate the effect of air pollutant level on the sepsis-related hospital admissions, for the years 2017–18, using data from six cities in Sichuan, China. Potential effect modifications by age and sex were also explored. The effects of air pollutant on hospital stays for sepsis were also quantified.

Results

Positive associations between short-term exposure to NO₂ and O₃ and risk of sepsis-related hospital admissions and stays were found. Each 10 μg/m³ increase in short-term NO₂ at lag 03 and O₃ at lag 4 was associated with an increase of 2.76% (95% CI: 0.67, 4.84%) and 0.64% (95% CI: 0.14, 1.14%) hospital admissions, respectively. An increase of 0.72% (95% CI: 0.05, 1.40%) hospital stay was associated with 10 μg/m³ increase in O₃ concentration at lag 4. Besides, the adverse effect of exposure to NO₂ was more significant in males and population aged less than 14 years; while more significant in females and population aged 14 ~ 65 and over 65 years for exposure to O₃. These associations remained stable after the adjustment of other air pollutants.8.

Conclusion

Exposure to ambient NO₂ and O₃ may cause substantial sepsis hospitalizations, and hospital stays in Sichuan, China. These associations were different in subgroup by age and sex.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11220-x.

Pollutant-sex specific differences in respiratory hospitalization and mortality risk attributable to short-term exposure to ambient air pollution

BACKGROUND

Many studies have reported associations of individual pollutants with respiratory hospitalization and mortality based on different populations, which makes it difficult to directly compare adverse health effects among multiple air pollutants.

OBJECTIVES

The study goal is to compare acute respiratory-related hospitalization and mortality associated with short-term exposure to three ambient air pollutants and analyze differences in health risks by season, age and sex.

METHODS

Hourly measurements of air pollutants (ozone, NO₂, PM_2.5) and temperature were collected from ground-monitors for 24 cities along with daily hospitalization (1996-2012) and mortality (1984-2012) data. National associations between air pollutant and health outcome were estimated for season (warm, cold vs. year-round), age (base ≥ 1, seniors > 65), and sex (females ≥ 1 and males ≥ 1) using Bayesian hierarchical models.

RESULTS

Overall, the three air pollutants were significantly associated with acute respiratory health outcomes at different lag-days. For respiratory hospitalization, the increased risks in percent changes with 95% posterior intervals for a 10-unit increase in each pollutant were: ozone (lag1, 0.7% (0.4, 0.9)), NO₂ (lag0, 0.7% (0.1, 1.4)), and PM_2.5 (lag1, 1.3% (0.7, 1.9)). For respiratory mortality: ozone (lag2, 1.2% (0.4, 1.9)), NO₂ (lag1, 2.1% (0.6, 3.5)), and PM_2.5 (lag1, 0.6% (-1.0, 2.2)). While some differences in risk were observed by season and age group, sex-specific differences were more pronounced. Compared with males, females had a higher respiratory mortality risk (1.8% (0.6, 2.9) vs 0.5% (-0.3, 1.3)) from ozone, a higher respiratory hospitalization risk (0.9% (0.0, 1.8) vs 0.6% (-0.3, 1.4)) but lower mortality risk (1.4% (-1.0, 3.7) vs 2.2% (0.4, 4.0)) from NO₂, and a lower hospitalization risk (0.7% (-0.2, 1.7) vs 1.8% (1.0, 2.6)) from PM_2.5.

CONCLUSION

This study reports significant health effects of short-term exposure to three ambient air pollutants on respiratory hospitalization (ozone≈NO₂ < PM_2.5 per-10 unit; ozone>NO₂ ≈ PM_2.5 per-IQR) and mortality (ozone≈NO₂ > PM_2.5) in Canada. Pollutant-sex-specific differences were found, but inconclusive due to limited biological and physiological explanations. Further studies are warranted to understand the pollutant-sex specific differences.