Coarse particles (PM2.5-10) and cause-specific hospitalizations in southwestern China: Association, attributable risk and economic costs

The impact of ambient air pollution on hospital admissions, length of stay and hospital costs for patients with diabetes mellitus and comorbid respiratory diseases in Panzhihua, Southwest China

Background

There is limited evidence on association between air pollutants and hospital admissions, hospital cost and length of stay (LOS) among patients with diabetes mellitus (DM) and comorbid respiratory diseases (RD), especially in low- and middle-income countries (LMICs) with low levels of air pollution.

Methods

Daily data on RD-DM patients were collected in Panzhihua from 2016 to 2020. A generalised additive model (GAM) was used to explore the effect of air pollutants on daily hospital admissions, LOS and hospital cost. Attributable risk was employed to estimate RD-DM's burden due to exceeding air pollution exposure, using both 0 microgrammes per cubic metre (μg/m3) and WHO's 2021 air quality guidelines as reference.

Results

For each 10 ug/m3 increase of particles with an aerodynamic diameter <2.5 micron (μm) (PM2.5), particles with an aerodynamic diameter <10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3), the admissions of RD-DM patients increased by 7.25% (95% CI = 4.26 to 10.33), 5.59% (95% CI = 3.79 to 7.42), 10.10% (95% CI = 7.29 to 12.98), 12.33% (95% CI = 8.82 to 15.95) and -2.99% (95% CI = -4.08 to -1.90); per 1 milligramme per cubic metre (mg/m3) increase of carbon monoxide (CO) corresponded to a 25.77% (95% CI = 17.88 to 34.19) increment for admissions of RD-DM patients. For LOS and hospital cost, the six air pollutants showed similar effect. Given 0 μg/m3 as the reference, NO2 showed the maximum attributable fraction of 32.68% (95% CI = 25.12 to 39.42%), corresponding to an avoidable burden of 5661 (95% CI = 3611 to 5860) patients with RD-DM.

Conclusions

There is an association between PM2.5, PM10, SO2, NO2, and CO with increased hospital admissions, LOS and hospital cost in patients with RD-DM. Disease burden of RD-DM may be improved by formulating policies related to air pollutants exposure reduction, especially in LMICs with low levels of air pollution.

Attributable risk and economic burden of pneumonia among older adults admitted to hospital due to short-term exposure to airborne particulate matter: a time-stratified case-crossover study from China

Many studies have proven the relationship between air pollutants and respiratory diseases, but few studies have assessed the impacts of air particulate matter exposure on older patients with pneumonia. This study aimed to reveal the impacts of short-term exposure to air particulate matter on the daily number of older adult patients hospitalized due to pneumonia and calculate the economic costs attributable to this exposure. We collected inpatient data from 9 city hospitals in Sichuan Province, China, from January 1, 2018, to December 31, 2019, and calculated odds ratios and 95% confidence intervals using a time-stratified case-crossover study design and an attributable risk model to calculate the economic burden due to particulate matter pollution. It was found that for every 10 μg/m³ increase in PM_2.5 and PM₁₀ concentrations, the daily number of older adult pneumonia inpatients increased by 1.5% (95% CI: 1.010-1.021) and 1.0% (95% CI: 1.006-1.014), respectively. Those 65 ~ 79 years old were more susceptible to air particulate pollutants (P < 0.05). During the study period, the total hospitalization costs and out-of-pocket expenses attributable to PM_2.5 and PM₁₀ exposure were 44.60 million CNY (6.22%) and 16.03 million CNY (6.21%), respectively, with PM_2.5 being the primary influencing factor. This study revealed the relationship between particulate matter pollution and pneumonia among older adults. The role of policies to limit particulate matter concentrations in reducing disease burden among older adults can be further explored.

Overview of particulate air pollution and human health in China: Evidence, challenges, and opportunities

Ambient particulate matter (PM) pollution in China continues to be a major public health challenge. With the release of the new WHO air quality guidelines in 2021, there is an urgent need for China to contemplate a revision of air quality standards (AQS). In the recent decade, there has been an increase in epidemiological studies on PM in China. A comprehensive evaluation of such epidemiological evidence among the Chinese population is central for revision of the AQS in China and in other developing countries with similar air pollution problems. We thus conducted a systematic review on the epidemiological literature of PM published in the recent decade. In summary, we identified the following: (1) short-term and long-term PM exposure increase mortality and morbidity risk without a discernible threshold, suggesting the necessity for continuous improvement in air quality; (2) the magnitude of long-term associations with mortality observed in China are comparable with those in developed countries, whereas the magnitude of short-term associations are appreciably smaller; (3) governmental clean air policies and personalized mitigation measures are potentially effective in protecting public and individual health, but need to be validated using mortality or morbidity outcomes; (4) particles of smaller size range and those originating from fossil fuel combustion appear to show larger relative health risks; and (5) molecular epidemiological studies provide evidence for the biological plausibility and mechanisms underlying the hazardous effects of PM. This updated review may serve as an epidemiological basis for China’s AQS revision and proposes several perspectives in designing future health studies.

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Acute effects of PM are smaller in China compared with developed countries

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Health effects caused by PM depend on particle composition, source, and size

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There are no thresholds for the health effects of PM

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Mechanistic studies support the biological plausibility of PM’s health effects

Gaseous air pollutants and hospitalizations for mental disorders in 17 Chinese cities: Association, morbidity burden and economic costs

The short-term morbidity effects of gaseous air pollutants on mental disorders (MDs), and the corresponding morbidity and economic burdens have not been well studied. We aimed to explore the associations of ambient sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃) and carbon monoxide (CO) with MDs hospitalizations in 17 Chinese cities during 2015-2018, and estimate the attributable risk and economic costs of MDs hospitalizations associated with gaseous pollutants. City-specific relationships between gaseous pollutants and MDs hospitalizations were evaluated using over-dispersed generalized additive models, then combined to obtain the pooled effect. Concentration-response (C-R) curves of gaseous pollutants with MDs from each city were pooled to allow regional estimates to be derived. The morbidity and economic burdens of MDs hospitalizations attributable to gaseous pollutants were further assessed. A total of 171,939 MDs hospitalizations were included. We observed insignificant association of O₃ with MDs. An interquartile range increase in SO₂ at lag0 (9.1 μg/m³), NO₂ at lag0 (16.7 μg/m³) and CO at lag2 (0.4 mg/m³) corresponded to a 3.02% (95%CI: 0.72%, 5.38%), 5.03% (95%CI: 1.84%, 8.32%) and 2.18% (95%CI: 0.40%, 4.00%) increase in daily MDs hospitalizations, respectively. These effects were modified by sex, season and cause-specific MDs. The C-R curves of SO₂ and NO₂ with MDs indicated nonlinearity and the slops were steeper at lower concentrations. Overall, using current standards as reference concentrations, 0.27% (95%CI: 0.07%, 0.48%) and 0.06% (95%CI: 0.02%, 0.10%) of MDs hospitalizations could be attributable to extra SO₂ and NO₂ exposures, and the corresponding economic costs accounted for 0.34% (95%CI: 0.08%, 0.60%) and 0.07% (95%CI: 0.03%, 0.11%) of hospitalization expenses, respectively. Moreover, using threshold values detected from C-R curves as reference concentrations, the above mentioned morbidity and economic burdens increased a lot. These findings suggest more strict emission control regulations are needed to protect mental health from gaseous pollutants.

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.

Differential effects of size-specific particulate matter on lower respiratory infections in children: A multi-city time-series analysis in Sichuan, China

Evidence on the short-term effects of size-specific particulate matter with aerodynamic diameter ≤2.5 μm (PM_2.5), ≤10 μm (PM₁₀), and their difference (PM_C) on children's Lower Respiratory Infections (LRI) is scare. This study aimed to estimate the differential effects of three size-specific PM on hospitalizations of children aged <18 years for pneumonia and bronchitis in 18 cities of southwestern China. The city-specific association was firstly estimated using the over-dispersed generalized additive model and then combined to obtain the regional average association. Further, to evaluate the robustness of the key findings, subgroup analyses and co-pollutant models were constructed. PM-related risks of LRI differed by PM fractions and cause-specific LRI. A 10 μg/m³ increment in PM_2.5_lag03, PM₁₀_lag06, and PM_C_lag06 was associated with a 0.79% (95% CI: 0.29%, 1.29%), 0.77% (95% CI: 0.13%, 1.41%), and 2.33% (95% CI: 1.23%, 3.44%) increase in children's LRI hospitalizations, respectively. After adjustment for gaseous pollutants, adverse effects of the three types of size-specific PM on pneumonia hospitalizations were stable, ranging from 0.29% (95% CI: 0.05%, 0.54%) for PM_2.5-2.50% (95% CI: 1.38%, 3.64%) for PM_C. Additionally, PM_C-related risk of bronchitis hospitalizations remained stable after adjustment for gaseous pollutants. Associations of pneumonia with PM_C and PM₁₀ in infants, bronchitis with PM_2.5 in children aged 6-17 years, pneumonia and bronchitis with PM_2.5, PM_C, and PM₁₀ in children aged 1-5 years were all statistical significant. Specifically, the effects of PM_2.5 on LRI hospitalizations increased by age, with the highest effect of 1.72% (95%CI: 1.01%, 2.43%) in children aged 6-17 years. Our study provided evidence for short-term effects of different PM fractions on children LRI hospitalizations in Southwestern China, which will be useful for making and promoting policies on air quality standards in order to protect children's health.