• Posted February 27, 2023

In Stockholm Study, As City Air Improved So Did Kids' Lung Capacity

Children in Sweden's capital can breathe a little easier.

As Stockholm's air has gotten cleaner, young people's lungs have gotten stronger, new research shows. The findings could have implications for cities worldwide.

While the adverse impact of air pollutants on kids' lung health is well-documented, the impact of changes in air quality on lung development is less studied, researchers noted.

Children's lung health greatly affects their future risk of developing chronic lung diseases.

"Fortunately, we've seen a decrease in air pollutants and therefore an increase in air quality in Stockholm over the past 20 years,"said co-author Dr. Erik Melén, a pediatrician and professor in the Department of Clinical Research and Education at the Karolinska Institute in Stockholm. "We therefore also wanted to examine if the lungs of children also improved during this period."

For the study, researchers used data from the BAMSE project, which is following about 4,000 individuals born between 1994 and 1996. Participants completed questionnaires at age 8, 16 and 24 and had lung function tests.

Researchers also estimated concentrations of airborne pollutants, mostly from traffic, at sites where participants lived from birth until early adulthood.

Air pollution was roughly 40% lower in Stockholm between 2016 and 2019 than it was between 2002 and 2004. At some locations, it decreased by 60%. Others have had no significant difference in air quality.

"When we compare the individuals living in the areas in which air quality has improved and those in which it hasn't, we find that lung function improved by a few percent in the participants in the young adult age bracket,"said first author Zhebin Yu, a postdoctoral researcher at Karolinska's Institute of Environmental Medicine. "But above all we could see a 20% lower risk of having significantly impaired lung function."

Researchers concluded that lower exposure to airborne pollutants, even at relatively low levels, was associated with improvements in lung development from childhood to early adulthood.

"It is ultimately of great importance since the lung function that children and adolescents develop as they grow up persists into adulthood,"Melén said. "If you have reduced lung function as an adult, you run a greater risk of chronic lung diseases like COPD, cardiovascular disease and premature death. So by improving air quality, we reduce the likelihood of children developing chronic diseases later in life."

Past research from the BAMSE project has shown that lung function growth can both improve and deteriorate over time. These new results show that air pollution can play an important part in this.

"Airborne pollutants that are by nature persistent are a great worry and our study clearly indicates that efforts to improve air quality have paid off, with quantifiable improvements in child and adolescent health,"Melén said.

Researchers would now like to examine potential advantages of cleaner air for lung diseases like asthma, bronchitis and prodromal COPD as well as for heart disease and type 2 diabetes.

Study findings were recently published in the European Respiratory Journal.

More information

The National Institutes of Health has more on air pollution and health.

SOURCE: Karolinska Institute, news release, Feb. 23, 2023