medwireNews: Research presented in two studies at the ERS Congress 2024 suggests that high levels of ambient air pollution can worsen respiratory conditions, increasing the progression from asthma to chronic obstructive pulmonary disease (COPD), and the need for hospitalization.
The first study looked at the effect of pollution on the risk for patients with asthma to develop COPD, which occurs in 10–30% of people, researcher Yutong Samuel Cai (University of Leicester, UK) told delegates in Vienna, Austria.
He reported that in their study “for each 10 µg/m3 higher exposure of PM [particulate matter]2.5 and [nitrogen dioxide], the risk increased by 79% and 13%, respectively.”
The team identified 46,832 individuals with asthma from the UK Biobank (2006–2010) and used land-use regression models to estimate baseline levels of PM2.5 and nitrogen dioxide where they lived.
Over a median 8.1 years of follow-up, 3750 (8%) patients developed COPD and the risk increased significantly by 19% and 24% among individuals living in areas with the highest levels (quartile 4) of PM2.5 and nitrogen dioxide exposure versus the lowest levels (quartile 1).
There was evidence of a dose-response relationship with nitrogen dioxide, whereas only the highest PM2.5 levels were significantly associated with COPD risk.
For every interquartile range (1.06 µg/m3 for PM2.5 and 7.63 µg/m3 for nitrogen dioxide), the risk for developing COPD increased by 6% and 10%, respectively, after accounting for covariates, such as sex, age, ethnicity, deprivation, education, smoking, alcohol consumption and BMI.
Cai noted that “adverse effects could be observed at concentrations as low as 8 µg/m3 for PM2.5 and 12 µg/m3 for nitrogen dioxide.
However, levels of PM2.5 or nitrogen dioxide were only significantly associated with the risk for COPD in patients who were at high genetic risk for asthma–COPD overlap, he pointed out.
For the second study – The Life-GAP project – Shanshan Xu (University of Bergen, Norway) and colleagues studied the long-term effects of air pollution and green space exposure on respiratory emergency room visits and hospitalizations for respiratory conditions across seven Northern European cities from the European Community Respiratory Health Survey III.
These were Reykjavik in Iceland; Bergen in Norway; Aarhus in Denmark; Umea, Uppsala, and Gothenburg in Sweden; and Tartu in Estonia.
The team used air dispersion models to measure annual exposures to PM2.5 and PM10, black carbon, nitrogen dioxide, and ozone around the homes of 1675 individuals in 1990 and 2000. They also determined the level of greenness based on the normalized different vegetation index using satellite data.
Over an average follow-up of 11.3 years, respiratory conditions led to hospitalization in 48 of the participants and presentation to the emergency department in 119.
Higher ambient levels of PM2.5, PM10, black carbon, and nitrogen dioxide were significantly associated with an increased risk for respiratory hospitalizations, said Xu.
Specifically, in 1990, the risk for respiratory hospitalization was increased 1.45-, 1.39-, 1.36- and 1.30-fold with each interquartile range increase in PM2.5, PM10, black carbon, nitrogen dioxide, respectively. The results were similar for exposure in 2000.
PM2.5 and PM10 were also associated with a higher risk for respiratory emergency room visits, whereas ozone was not associated with either outcome.
Xu highlighted that increased levels of greenness had a protective effect against respiratory hospitalizations; however, it was positively associated with emergency room visits, particularly among individuals with atopic status, namely those with nasal allergies and hay fever.
She explained in a press release: “Air pollution causes persistent inflammation and oxidative stress in the respiratory system. These harmful processes contribute to the development and exacerbation of chronic respiratory diseases, which can escalate into severe health episodes requiring hospital care.
“It is also likely that long-term exposure to air pollution could lead to a decreased tolerance or increased sensitivity to these pollutants, explaining why even moderate or low levels might cause severe health effects in certain populations.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2024 Springer Healthcare Ltd, part of the Springer Nature Group
