Air Pollution and Genetic Risk Together Drive Asthma Progression to COPD, Finds Study
UK: Long-term exposure to air pollution may significantly raise the risk of developing chronic obstructive pulmonary disease (COPD) among individuals with asthma—especially those with a heightened genetic predisposition—according to a new study published in Thorax, a journal of the BMJ.
Conducted by Guoxing Li and colleagues from the Environmental Research Group at Imperial College London, the study examined the joint influence of air pollution and genetic susceptibility on the progression from asthma to COPD. The research sheds light on how environmental and genetic factors interact to contribute to this serious respiratory condition.
Drawing on data from the UK Biobank, the study followed 46,832 individuals with asthma over a median period of 10.8 years. During this time, 3,759 participants developed COPD. Researchers used land-use regression models to estimate baseline exposure levels to fine particulate matter (PM2.5) and nitrogen dioxide (NO₂), two common air pollutants.
The key findings of the study were as follows:
- The findings revealed that each interquartile range (IQR) increase in PM2.5 was associated with a 7% higher risk of developing COPD (hazard ratio [HR] 1.07), while a similar increase in NO₂ exposure raised the risk by 10% (HR 1.10).
- Even relatively low levels of air pollution—just 8 µg/m³ for PM2.5 and 12 µg/m³ for NO₂—were enough to elevate the risk.
- To assess the role of genetics, the researchers calculated polygenic risk scores based on newly identified genetic variants linked to the coexistence of asthma and COPD.
- Individuals with the highest genetic susceptibility faced an even greater risk of disease progression.
- In this subgroup, each IQR increase in air pollution was linked to a 13% rise in COPD risk (HR 1.13).
- There was a statistically significant interaction between air pollution and genetic predisposition, indicating that the combined impact is greater than the sum of individual risks.
The study highlights an important and previously under-recognized health concern: the transition from asthma to COPD is not only influenced by genetic makeup but also by ongoing environmental exposures, even at pollutant levels considered to be within acceptable limits.
Given the chronic nature and substantial health burden of COPD, these findings underscore the need for more stringent air quality standards and personalized healthcare strategies. Individuals with asthma, particularly those with known genetic vulnerability, may benefit from early interventions aimed at reducing exposure to air pollution.
The authors emphasize that this study adds critical evidence supporting the need for public health policies that take both environmental and genetic risk factors into account, especially for vulnerable respiratory patients.
Reference:
Li G, Zhang K, Yang T, et alAir pollution, genetic susceptibility and risk of progression from asthma to COPDThorax Published Online First: 21 July 2025. doi: 10.1136/thorax-2024-222871
