A Child's Genetic Risk for Lung Disease Only Shows Up in Polluted Air, Study Finds

Chronic obstructive pulmonary disease (COPD), a serious, incurable lung disease common in older people, may have roots that reach back decades, according to new research presented at the European Respiratory Society (ERS) Congress in Barcelona. The study found that babies born with a higher genetic risk for COPD showed reduced lung function growth between birth and age six, but only among children also exposed to higher levels of air pollution.

"COPD develops through a combination of genetic factors and environmental exposures across the lifespan, leading to an accelerated decline in lung function," said Carla da Silva Sena of University Children's Hospital Basel UKBB, Switzerland, who presented the research. She said COPD may result from lung function trajectories established early in life, and that studying these patterns from the earliest stages of life is key to understanding how the disease develops.

The research drew on 484 children in the Basel-Bern Infant Lung Development (BILD) study, an ongoing Swiss birth cohort of children born between 1999 and 2020. Lung function was measured in the first month of life using an infant breathing test, and again at age six using spirometry, a test in which a person breathes in deeply and blows out as hard as possible. Researchers also estimated each child's exposure to outdoor air pollution and calculated a polygenic risk score, a measure combining many small genetic differences linked to COPD risk in adults, from blood samples.

Genetic risk for COPD was linked to reduced lung function growth between birth and age six, but only among children from areas with the highest fine-particle (PM2.5) pollution, averaging 15.3 micrograms per cubic metre; the effect was much weaker in less polluted areas. A similar pattern appeared with higher nitrogen dioxide levels, averaging 28.3 micrograms per cubic metre.

Barbara Hoffmann of the University of Dusseldorf, who chairs the ERS Advocacy Council and was not involved in the research, said the findings show how genes and the early-life environment combine to set children on a path to lung disease much later, which may help explain why COPD also occurs in people who never smoked. The researchers plan to follow the children into adolescence and adulthood to see whether the differences persist.