How Air Pollution Affects Lower Respiratory Infections in Adults: Key Insights

Air pollution is widely recognized as a risk factor for respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). However, its impact on lower respiratory infections, which affect the lungs, bronchi, and alveoli, is less understood, especially among adults. A recent study from the Barcelona Institute for Global Health (ISGlobal) addresses this gap by examining the effects of air pollution on hospital admissions for lower respiratory tract infections in adults. The findings have been published in the journal Environment International.

Study Reveals Risks to Lower Respiratory Tract Infections

The research indicates that long-term exposure to fine particulate matter (PM2.5), coarse particulate matter (PM10), nitrogen dioxide (NO2), and ozone (O3) increases hospital admissions for lower respiratory tract infections in adults. Notably, these associations were stronger in men, adults aged 65 or older, and those with hypertension.

This study involved 3.8 million adults from the COVAIR-CAT cohort, a comprehensive database of 7.7 million people aligned with the healthcare system of Catalonia. Researchers utilized exposure models to assess annual average concentrations of the four pollutants during the warm season (May through September) from 2018 to 2020 at the participants’ residences. Hospitalization records, mortality rates, and comorbidities were obtained from administrative databases. The study analyzed admissions for all lower respiratory infections, as well as influenza and pneumonia specifically.

The association between air pollution and hospital admissions for lower respiratory tract infections was observed even at pollution levels below current EU air quality standards. It is crucial to adopt stricter air quality standards, as more ambitious measures to reduce air pollution would decrease hospital admissions and protect vulnerable populations.

Anna Alari, ISGlobal researcher and first author of the study

Increased Risks Among Vulnerable Groups

The study found that air pollution had a more significant impact on hospitalizations in adults over 65 and those with comorbidities. Specifically, elevated air pollution levels were associated with about three times higher hospitalization rates for lower respiratory infections among people aged 65 and older compared to younger individuals.

Exposure to high levels of NO2, PM2.5, or PM10 was linked to approximately a 50% increase in hospital admissions for men, while the association was about 3% higher for women. The team noted a similar pattern for hospital admissions for influenza and pneumonia, but with smaller associations compared to lower respiratory infections in general.

Cathryn Tonne, the senior author of the study, commented, “This may be due to the influence of available vaccines against the pathogens responsible for influenza and most cases of pneumonia.”

The Implications of These Findings

These findings highlight the importance of implementing stricter air quality standards beyond current EU guidelines. Reducing exposure to pollutants like PM2.5, PM10, NO2, and ozone can significantly lower hospital admissions for lower respiratory tract infections. The study underscores the need for targeted protective measures for vulnerable populations, including men, older adults, and individuals with hypertension.

Conclusion

The research from ISGlobal provides compelling evidence of the direct link between air pollution and hospital admissions for lower respiratory tract infections in adults. By identifying vulnerable groups and stressing the need for stricter air quality standards, these insights can guide policymakers and public health officials in crafting effective strategies to protect public health.

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