Air pollution increases risks for respiratory ED visits, hospitalizations
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Key takeaways:
- Particulate matter, black carbon and nitrogen dioxide were associated with increased risks for respiratory hospitalizations.
- PM2.5 and PM10 were associated with a higher risk for respiratory ED visits.
Air pollution increased the risk for ED visits and hospitalizations due to asthma and other respiratory diseases, according to a poster presented at ERS Congress 2024.
Presented by Shanshan Xu, PhD candidate, department of global public health and primary care, University of Bergen, the study comprised 1,675 patients treated at seven study centers in five Northern European countries between 2000 and 2010.
Data were derived from Xu S, et al. Abstract PA468. Presented at ERS Congress 2024, Vienna; Sept. 5-7, 2024.
“This study, conducted under the Life-GAP project, was initiated to gain a deeper understanding of the long-term effects of air pollution and greenness on respiratory health care utilization,” Xu told Healio. “Our goal was to shed light on how these environmental factors influence respiratory health over time.”
The researchers compared the respiratory health of these patients with their long-term exposure to particulate matter, black carbon, nitrogen dioxide and ozone based on air dispersion models and greenness, or the amount of vegetation surrounding their home according to satellite data and based on the normalized difference vegetation index (NDVI).
“We observed a consistent association between long-term exposure to air pollution and increased risks of emergency room visits and hospitalizations across various time windows — 1990, 2000, and the average from 1990 to 2000,” Xu said.
During the follow-up period, which averaged 11.3 years, 119 patients reported respiratory ED visits, and 48 reported respiratory hospitalizations.
Risks for hospitalization due to respiratory diseases increased with exposure to particulate matter at the 2.5 µm (PM2.5) and 10 µm (PM10) scales, black carbon and nitrogen dioxide despite relatively low air pollution levels in Northern Europe, the researchers said.
“Data from 1990 revealed a significant relationship between exposure to particulate matter and both emergency room visits and hospitalizations,” Xu said. “Other pollutants such as nitrogen dioxide and black carbon from the same 1990 exposure window also showed statistically significant associations with respiratory hospitalizations.”
For 1990, risks for hospitalization rose with each interquartile range increase in pollutants, including odds ratios of 1.45 (95% CI, 1.07-1.96) for PM2.5, 1.39 (95% CI, 1.07-1.78) for PM10, 1.36 (95% CI, 0.98-1.88) for black carbon and 1.3 (95% CI, 0.94-1.8) for nitrogen dioxide. The risks for hospitalization with exposure were similar in 2000, the researchers said, although there was less precision.
There also were associations between PM2.5 and PM10 and higher risks for respiratory ED visits, although there were no clear associations between ozone and respiratory ED visits or hospitalizations.
These results correspond with the researchers’ previous studies, which showed that exposure in 1990 could have a significant impact on all-cause mortality 20 to 30 years later, Xu continued.
“Given the possibility of extended latency periods, these results suggest that air pollution exposure far back in time may have enduring effects on the severe episodes of respiratory conditions that require hospital care,” Xu said.
Risks for respiratory hospitalization seemed to fall with greenness, the researchers continued, although there was a positive association between greenness and respiratory ED visits, especially with atopic status, defined by nasal allergies and hay fever.
“Greenness exposure could have adverse effects on those with atopic conditions, potentially exacerbated by the presence of pollen or other aeroallergens, leading to increased emergency room visits,” Xu said.
Specifically, the researchers noted significant interactions between NDVI and atopic status on respiratory ED visits across exposures in 1990 (P = .014) and 2000 (P < .001) as well as across mean exposures between 1990 and 2000 (P = .013).
“This interaction underscores the complex relationship between environmental factors and genetic predispositions in determining health outcomes,” Xu said.
Xu noted the significant limitations of the study, especially its lack of access to short-term exposure data that could be more relevant for ED visits and immediate reactions to aeroallergens.
“Therefore, the findings related to greenness should be interpreted with caution,” she said.
Still, Xu called the findings of the study particularly surprising and significant because of the chronic nature of respiratory diseases, which typically develop after prolonged exposures over many years or decades.
“These conditions arise from a complex interplay of environmental exposures and genetic factors that lead to structural changes in the respiratory tract and a gradual reduction in lung function,” she said.
Air pollution causes persistent inflammation and oxidative stress in the respiratory system, the researchers said, contributing to the development and exacerbation of chronic respiratory diseases, which can escalate into severe health episodes requiring hospital care.
Long-term exposure to air pollution also may likely lead to decreased tolerance or increased sensitivity to these pollutants, the researchers continued, which would explain why even moderate or low levels might cause severe health effects in certain populations.
In fact, the severity of long-term effects of air pollution and other environmental exposures are comparable to the progressive damage caused by cigarette smoking, Xu said.
“While immediate effects may not be fatal, sustained exposure results in serious health complications and increased health care utilization,” she said. “Our research provides crucial data on how different pollutants contribute to these long-term health challenges.”
Physicians can incorporate tailored screening and monitoring for patients who have been exposed to air pollution and pollen allergens, particularly those patients who have known sensitivities, Xu said.
Also, physicians can educate patients about strategies for minimizing exposure such as using air purifiers during high pollen seasons and staying informed about daily air quality and pollen counts, she said, which can significantly mitigate health risks.
“Additionally, advocating for stricter air quality and environmental controls can help reduce overall exposure to these pollutants,” Xu said. “By addressing these environmental factors comprehensively, doctors can not only manage immediate symptoms more effectively but also contribute to long-term public health improvements.”
Reference:
- Xu S, et al. Abstract PA468. Presented at ERS Congress 2024, Vienna; Sept. 5-7, 2024.
For more information:
Shanshan Xu can be reached at shanshanxuli@gmail.com.
Perspective
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The findings of increased hospitalizations for chronic respiratory conditions such as asthma related to worsening levels of air pollution, particularly PM, are not surprising and have been cited in previous studies. Of interest was the protective effect of greenness with regard to the hospitalizations, as well as the increased risk for ED visits related to atopic disease flares in the “greener” areas.
My experience has been similar to this study. We see higher rates of hospitalizations related to poor air quality and spikes in ED visits during high pollen or allergy seasons that would reflect the greenness effect measured in the study.
Awareness is the key factor for physicians to help patients mitigate the health impacts of air pollution. Doctors need to educate their patients, especially those with chronic lung conditions, to get in the habit of being aware of outdoor conditions related to particle pollution and ozone pollution.
Patients should understand that their airways can be inflamed by exposure to high PM and ozone. Having them check the daily air quality index through free websites or apps such as airnow.gov can be a useful tool to help patients determine how much activity outdoors should be limited during bad air quality days.
At a policy level, ongoing support of the work that the Environmental Protection Agency does in monitoring and setting standards (National Ambient Air Quality Standards or NAAQS) would be important in helping to decrease PM and ozone levels in the long term. Great strides have been made in the U.S. air quality since the passage of the Clean Air Act in 1970, but ongoing work is needed.
Also, governmental policies need to promote and mandate adequate and equitable coverage of medications and access to care by governmental (Medicaid, Medicare) and private insurers for individuals who have chronic conditions such as asthma and COPD.
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