According to a Reuters news report, a European study suggests that exposure to air pollution early in life may contribute to the development of asthma in childhood and adolescence. For the study, researchers followed more than 14,000 children from birth through ages 14 to 16 years, and Ulrike Gehring, PhD, lead author of the study, and colleagues examined concentrations of nitrogen dioxide to explore the link between asthma and air pollution. Nitrogen dioxide is a byproduct of fossil fuels that contribute to smog, and particulate matter is a mixture of solid particles and liquid droplets.
The research team then examined questionnaire data about the children’s respiratory health that was collected several times during childhood. Parents were asked if their child was diagnosed with asthma and had sneezing, congestion or itchy watery eyes when they didn’t have cold, as well as if the child was prescribed asthma drugs or experienced wheezing. The young participants included kids from Sweden, The Netherlands, and Germany.
The researchers found that those born in communities with more polluted air were more likely to develop asthma than other kids, particularly after age 4. According to Reuters, overall, the risk of asthma by ages 14 to 16 years increased with increasing exposure to nitrogen dioxide and particulate matter at the birth address, but not with exposure levels for the address at the end of the study. The researchers did not find a link between allergies and air pollution exposure.
The researchers acknowledge that one limitation of the study is that researchers used air pollution measurements from 2008 to 2010 for the entire duration of follow-up, while the team also didn’t look at air quality at school or daycare centers, which may differ from where the children lived. The Reuters news report also indicates that it is also possible that children growing up near heavily trafficked roadways may differ from kids who grow up in other locations that also increase asthma risk.
Steve Georas, who wrote an accompanying editorial, says that even so the findings add to a growing body of research linking asthma to pollution. Georas states, “It is probably time to doubt no more that early life air pollution exposure is a risk factor for asthma for some children. What we need now are more studies to understand (why) some children are particularly susceptible to these adverse effects.”