Exposure to outdoor air pollution is linked to an increased risk of developing chronic obstructive pulmonary disease (COPD) and to decreased lung function, a UK study reports today.
Although lung function normally declines with age, new research by academics at the University of Leicester the Centre, which is published in the European Respiratory Journal says that air pollution may contribute to the ageing process.
Using data from the UK Biobank study, the team assessed more than 300,000 people to establish if air pollution exposure was linked to changes in lung function, and whether it affected participants’ risk of developing COPD.
Anna Hansell, professor of environmental epidemiology in the Centre for Environmental Health and Sustainability, and her team used a validated air pollution model to estimate the levels of pollution that people were exposed to at their homes when they enrolled in the UK Biobank study.
Participants answered detailed health questionnaires as part of the UK Biobank data collection, and lung function was measured using spirometry tests performed by medical professionals at Biobank assessment centres at enrolment between 2006 and 2010.
The research team then conducted multiple tests to see how long-term exposure to higher levels of the different air pollutants was linked to changes to participants’ lung function.
The data showed that for each annual average increase of five micrograms per cubic meter of PM2.5 in the air that participants were exposed to at home, the associated reduction in lung function was similar to the effects of two years of ageing.
When the researchers assessed COPD prevalence, they found that among participants living in areas with PM2.5 concentrations above World Health Organization (WHO) annual average guidelines of ten micrograms per cubic meter (10 µg/m3), COPD prevalence was four times higher than among people who were exposed to passive smoking at home, and prevalence was half that of people who have ever been a smoker.
Professor Hansell said: “In one of the largest analyses to date, we found that outdoor air pollution exposure is directly linked to lower lung function and increased COPD prevalence. We found that people exposed to higher levels of pollutants had lower lung function equivalent to at least a year of ageing.
“Worryingly, we found that air pollution had much larger effects on people from lower income households. Air pollution had approximately twice the impact on lung function decline and three times the increased COPD risk on lower-income participants compared to higher-income participants who had the same air pollution exposure.
“We accounted for participants’ smoking status and if their occupation might affect lung health and think this disparity could be related to poorer housing conditions or diet, worse access to healthcare or long-term effects of poverty affecting lung growth in childhood. However, further research is needed to investigate the differences in effects between people from lower- and higher-income homes.”
The research team are conducting further studies to look at whether genetic factors interact with air pollution and its effects on health.
Doiron D, de Hoogh K, Probst-Hensch N, et al. Air pollution, lung function and COPD: results from the population-based UK Biobank study. ERJ 9 July 2019.
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