MONTREAL — Exposure to air pollution accelerates lung aging and increases the risk of chronic obstructive pulmonary disease, new research suggests.
Dr. Dany Doiron and his colleagues studied the exposure of more than 300,000 people in Europe to particulate matter, fine particles and nitrogen dioxide — substances that come mainly from emissions by cars and factories.
"We know that lung function normally declines as we age, but our study suggests that air pollution may contribute to the aging process and adds to the evidence that breathing in polluted air harms the lungs," said Doiron, a researcher at the Research Institute of the McGill University Health Centre.
"We were surprised at the size of the association — so for each annual average exposure increase of five micrograms per cubic metre of fine particulates in the air that participants were exposed to at home, the associated reductions in lung functions were similar to the effect of two years of aging."
Researchers considered a number of factors that could impact the health of their subjects' lungs including age, sex, body mass index, income, education, employment, smoking and their exposure to second-hand smoke.
Such particulates are so thin that they can lodge deep in the lungs and contribute to chronic diseases. The World Health Organization recommends average annual concentrations of not more than 10 micrograms per cubic metre of air.
There was a 52 per cent increase in the odds of COPD for each five-micrograms-per-cubic-metre increase of fine particulate exposure, Doiron said.
COPD is a long-term condition linked to reduced lung function that causes inflammation in the lungs and a narrowing of airways making it difficult to breath. The study said it's the third leading cause of death in the world and the numbers are expected to rise over the next decade.
Those from less affluent backgrounds seemed particularly vulnerable to the effects of air pollution.
The study found the impact of pollution on lung function was twice as high among less fortunate participants, and their risk of COPD was three times greater.
"This is probably due to a number of factors, including a greater number of respiratory infections in children, poor housing and indoor air quality, and other conditions," he said.
Those results are all the more concerning as the air quality was not measured in highly polluted cities like Delhi, Beijing or Jakarta.
"There have been significant reductions in lung function even at relatively low concentrations of ... fine particles," said Doiron.
"Our results underline the importance of taking more action to fight against air pollution in our cities."
The study on European populations was one of the largest to date to examine the associations between air pollution exposure, lung function and COPD and gave researchers the statistical power to make the associations more precisely, Doiron said.
"It was over 10 times larger than previous studies in terms of numbers of individuals involved on European populations," he added.
The findings of the study were published this week in the European Respiratory Journal.