Study finds high levels of deadly blood cancer in Ontario industrial cities

A recent study from Montreal's McGill University Health Centre has found "striking" levels of a deadly blood cancer clustered in Ontario cities including Hamilton, Sarnia and Thunder Bay.

The peer-reviewed study, which was published in February in the journal Cancer, examined 18,085 cases of acute myeloid leukemia (AML) reported in Canada between 1992 and 2010.

Researchers discovered Ontario and P.E.I had "significantly higher" AML rates than the national average, with hotspots also found in Ontario cities like Sault Ste. Marie and St. Catharines.

"These results … reveal a striking geographic case clustering in industrial Ontario cities and potentially implicate exposure to materials/pollution from these plants as an important risk factor for developing AML in Canada," the study says.

The study also found that Sarnia, Sault Ste. Marie, Thunder Bay, Hamilton, and some other cities in Ontario had significantly higher mortality rates linked to AML than the Canadian average.

We've got a lot more work to do.- Lynda Lukasik, Environment Hamilton

A few other Ontario cities also had high mortality rates approaching "statistical significance," including St. Catharines, Kingston, Peterborough, Newmarket, Kitchener, Toronto, Windsor, Oshawa, and London.

The study was led by Ivan Litvinov, an assistant professor in the department of medicine and division of experimental medicine at McGill.

He called AML "one of the most deadly blood cancers."

"Particularly with Hamilton, of course we know there is a major industrial complex, and a number of highways that are running through the city," he said.

Benzene levels linked to cancer

The researchers also examined incidents of AML rates by postal code, and found that Hamilton postal codes L8H, L8K, and L8S were "high incidence," and not far from the city's industrial sector.

"Studying exposures in detail in these cities may hold the key to understanding risk factors for AML overall," the report says.

The Hamilton Industrial Environmental Association, which represents local industrial companies in the city, did not respond to requests for comment for this story.

Lynda Lukasik, executive director of Environment Hamilton, said the city has long been fighting to reduce pollutants — especially the carcinogen benzene, which the study identifies as "an important risk factor for AML."

"The levels are still too high to be truly acceptable for human health and the environment," she said. "We've got a lot more work to do."

This news won't shock Hamiltonians, she said, who have long heard about links between pollutants and cancer. Though efforts to clean up the airshed over many years have had a positive impact, studies like this one show the long term effects of polluting, she said. 

"In many ways, this is a legacy issue."

The study also found AML was being diagnosed in the N7V postal code in downtown Sarnia at rates more than three times the national average.

AML mortality was "markedly elevated" in Sarnia between 2000 to 2010, the study says. It also notes that Sarnia and its metropolitan area have the highest concentration of petrochemical plants in the country.

Smoking, obesity also considered risk factors

The Sarnia-Lambton Environmental Association (SLEA) declined an interview about the issue.

In a statement, association General Manager Vince Gagner referenced a health study being run by the province to obtain more information on how industrial pollution affects the region.

"While SLEA is not an expert on the information contained in this study, it seems there could be an opportunity for it to play a role in the health initiative underway with the Ontario Ministry of the Environment, Conservation and Parks," he said in an email.

"SLEA has always been supportive of initiatives regarding the health and wellbeing of the Sarnia-Lambton community."

Litvinov also pointed out that a variety of risk factors contribute to this type of cancer, including smoking, obesity and exhaust fumes.

He said he's hoping to see more work from government and regulatory bodies in these regions to continue to reduce emission levels.

"Many government officials are local residents of those communities, so I can't imagine them not being motivated to do what is necessary for the wellbeing of those communities, and to enforce the regulations that are already written in Canada," he said.

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