Asthma in childhood linked to air pollution

Children exposed to higher levels of air pollution are more likely to suffer asthma, a new study suggests.

Reduction in pollution levels in areas of high pollution may reduce the number of children who develop asthma, researchers said.

The new study, published in The BMJ, saw researchers examine data on Danish children born between 1997 and 2014.

They were then tracked, some until they were 15 years old, to see whether or not they developed asthma or a persistent wheeze.

A total of 122,842 children were identified as having developed asthma or a wheeze.

Youngsters exposed to higher levels of air pollution – measured through particulate matter or PM2.5 – were more likely to have asthma or a persistent wheeze.

Separate research from Asthma UK and the British Lung Foundation found that during lockdown, many people they work with noticed improvements in their symptoms – possibly due to lower levels of air pollution.

Meanwhile, the current study also found that asthma was more likely to be found among children whose parents also have the condition.

And it was also more likely among children whose mother’s smoked in pregnancy.

Children from wealthier backgrounds and those whose parents had a high level of educational achievement were less likely to have the condition.

The authors from Denmark wrote: “The findings of this study suggest that children exposed to higher levels of PM2.5 are more likely to develop asthma and persistent wheezing than children who are not exposed.

“Other risk factors associated with these outcomes were parental asthma, parental education, and maternal smoking during pregnancy.”

They added: “The results suggest that further reductions in PM2.5 might help to reduce the number of children who develop asthma and persistent wheezing in highly exposed populations.”

Commenting on the study, Zak Bond, policy officer at Asthma UK and the British Lung Foundation, said: “This is an interesting study, and while we require further substantiation, it clearly demonstrates the importance of tackling dirty air to protect our health.

“Fine particulate matter (PM2.5) is the most worrying type of pollution for lung health, and disproportionately impacts certain groups, including the very young, older people and people with lung conditions such as asthma.

“Our recent statistics show that one in four people with asthma in the UK noticed their symptoms improved during lockdown, likely as a result of the fall in air pollution levels.

“Asthma UK and the British Lung Foundation are campaigning for the government to back a strong new legal limit for PM2.5, in line with World Health Organisation guidelines, in the Environment Bill. It is time to reduce air pollution so everyone can breathe clean air with healthy lungs.”