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Researchers find association between air quality and developing asthma

Air quality may affect a person’s risk for developing incidence asthma, according to recent research published in The Lancet Respiratory Medicine.

“Our findings provide evidence for positive associations of exposure to NO₂ and PM_2.5 absorbance early in life with incidence and prevalence of asthma, but not rhinoconjunctivitis, throughout childhood and adolescence,” Ulrike Gehring, PhD, associate professor at the Institute for Risk Assessment Sciences at Utrecht University in Utrecht, Netherlands, and colleagues wrote. “The adverse effects of air pollution on asthma incidence and prevalence were more consistent after age 4 years than before that age.”

Gehring and colleagues evaluated 14,126 patients for incidence of asthma and rhinoconjunctivitis across four different birth cohort studies in Germany and Sweden. They measured the air quality at the participants’ addresses using reports of concentrations of nitrogen dioxide (NO₂) and particulate matter diameter of less than 2.5 μm (PM_2.5), less than 10 μm (PM₁₀), and between 2.5 and 10 μm (PM_coarse), according to the abstract. The researchers followed participants until age 14 to 16 years, performing a longitudinal analysis of the air quality at the participants’ birth addresses as well as their permanent addresses at final follow up.

Although the researchers observed no relation between rhinoconjunctivitis and air quality, they found a significant association between an increased exposure to NO₂ (adjusted OR = 1.13 per 10 μg/m³; 95% CI, 1.02-1.25) and absorbance of PM_2.5 (adjusted OR = 1.29 per 1 unit; 95% CI, 1-1.66) and developing asthma up to age 14 to 16 years, according to the abstract.

Gehring and colleagues also found a non-significant association between PM_2.5 and developing asthma (adjusted OR = 1.25 per 5 μg/m³; 95% CI, 0.94-1.66) and noted that the results were more consistent after age 4. – by Jeff Craven

Disclosure: The study was funded by the European Union. Please see the full study for a complete list of disclosures.