MedWire News: Traffic-related air pollution is associated with a poor symptom-based asthma score, research shows.
Stronger effects were observed among those free from asthma and respiratory symptoms at baseline, and this suggests that pollution caused by traffic might play a role in the onset of disease, according to researchers.
"Our results suggest that traffic-related pollution causes asthma symptoms and possibly asthma incidence in adults," write Benedicte Jacquemin (University Paris-Sud, Villejuif, France) and colleagues in the European Respiratory Journal.
Previous studies have shown that fluctuations in air pollution levels are associated with short-term effects among individuals with asthma. In adults, traffic-related pollutants have been linked with cough, bronchitis, and chronic obstructive pulmonary disease.
In this latest investigation, Jacquemin and colleagues also sought to explore the association between a previously developed asthma score and traffic-related air pollution. This novel asthma score, which ranges from 0 to 5 and is based on the frequency and severity of symptoms such as wheeze/breathlessness and chest tightness, allows researchers to measure asthma as continuous trait, thereby improving its power to identify risk factors.
In total, 4394 individuals aged 25 to 44 years were randomly selected from two health surveys.
The researchers found that the derived asthma score was positively associated with nitric oxide (NO2) levels, a marker for traffic-related air pollution (Ratio of the Mean asthma Score [RMS]=1.23).
In an analysis that excluded individuals with asthma and symptoms at baseline, the association between the asthma score and NO2 levels remained (RMS=1.25), reflecting asthma incidence, and was particularly strong among those with a high score.
Jacquemin and team conclude: “NO2 is associated with asthma score suggesting that traffic related air pollution causes asthma symptoms in adults. The stronger effects among those free of asthma and symptoms at baseline may indicate a role of pollution in the onset of asthma as well. This needs further investigation.”
They add: “The use of the asthma score offers very attractive alternatives to investigate the etiology of asthma and the course of this disease in adults.”
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