Kids born in Sarnia more likely to get asthma than those in Windsor or London, study shows

·2 min read
Oil from Western Canada makes it as far east as Sarnia, Ont., home to refineries like this one. Enbridge is proposing to reverse the flow of oil from the pipeline that connects Sarnia to Hamilton. (Dave Chidley/Canadian Press - image credit)
Oil from Western Canada makes it as far east as Sarnia, Ont., home to refineries like this one. Enbridge is proposing to reverse the flow of oil from the pipeline that connects Sarnia to Hamilton. (Dave Chidley/Canadian Press - image credit)

Kids born in Sarnia, Ont., home to Chemical Valley and its 60 industrial plants and oil refineries, are more likely to have asthma than those born in nearby cities, a population-based study by researchers at Lawson Health Research Institute and Western University shows.

Researchers followed 114,427 kids in Sarnia as well as London, Ont., and Windsor, Ont., born between 1993 and 2009 for 10 years. By age 10, nearly a quarter of kids in Sarnia were diagnosed with asthma, compared to 21 per cent in Windsor and 17 per cent in London.

"It's known that cities in Southwestern Ontario have varied levels of air pollution because of differences in industry and traffic," said researcher Dr. Dhenuka Radhakrishnan

"We wanted to see if children born in three cities had a different risk of developing asthma due to the differing air pollution levels in the three regions, even though the people living in these cities are otherwise comparable in many ways."

The findings confirm that air pollution exposure in the first year of life is associated with the development of asthma in children. Overall rates of new childhood asthma diagnosis in southwestern Ontario have been decreasing over time as air pollution levels decrease.

Members of the Aamjiwnaang First Nation have for years warned about the pollution in the Sarnia area and the higher levels of disease among its members.

A graph shows the proportion of children with asthma in three southwestern Ontario cities.
A graph shows the proportion of children with asthma in three southwestern Ontario cities. (Supplied by Health Lawson Research Institute.)

Researchers accounted for other risk factors associated with asthma, such as sex, socioeconomic status and urban versus rural setting. The findings were most apparent in the first two years of life, but persistent beyond the age of six.

Asthma is the most common chronic disease in Canadian kids and has a significant impact on quality of life. It's the leading cause of emergency department visits and hospital admissions in kids.

"It's important to find strategies to prevent asthma development and this study suggests that reducing air pollution exposure, including environmental causes, might reduce the number of children who suffer from asthma," said Dr. Salimah Shariff, a scientist at Lawson and professor at Western University.

There's also growing evidence that pollution exposure during pregnancy can influence whether kids get asthma, Shariff said.

"We need to carefully examine how reducing air pollution exposures within a geographic area translates to reductions in asthma development. Understanding the amount of air pollution that a mother and infant are exposed to, and how this impacts their personal risk, could enable regions to target safer levels for their residents," she said.