Should you dump your gas stove? The health-risks studies are inconsistent

A Canadian study suggests an association between household use of gas stoves and a higher risk of asthma in some kids. However, like other recent studies on the issue, the results were inconsistent.

Researchers acknowledged the findings suggest some health effects with gas stove use, but no direct connection to childhood asthma could be drawn.

That echoes similar findings elsewhere, but a study published last year in the United States associating gas stoves with childhood asthma added to the confusion.

WHAT WE CAN GLEAN FROM THE MOST RECENT DATA

The Canadian study, published June 9 in the Canadian Journal of Public Health, was based on questionnaires conducted by the CHILD Cohort Study to collect data on nearly 3,000 children born between 2009 and 2012 in Vancouver, Edmonton, Winnipeg and Toronto. The overall data in the project allows scientists to track the participants' environment and health, including onset of asthma, obesity, diabetes and other chronic diseases over many years.

Dr. Padmaja Subbarao, a respirologist and study co-author, said 5.5 per cent of children living in a Toronto home with an electric stove were diagnosed with asthma but that jumped to just over 10 per cent at age five for kids whose families used a gas stove.

She said asthma cases were likely higher in Toronto compared with Vancouver, where they were not statistically significant, because a milder climate in the West Coast city means people tend to open their windows, even in winter. That allows pollutants such as carbon monoxide and nitrogen oxides emitted by gas stoves to escape outdoors instead of staying inside and potentially irritating the lungs.

"It shows you that it's not as simple as saying you can't have a gas stove," Subbarao said. "It really depends on how you use it and the environmental characteristics that you live in."

Gas stoves have become a hot topic after several studies connected their use to childhood asthma.

A meta analysis of various studies published last December in the International Journal of Environmental Research and Public Health suggested 12.7 per cent of childhood asthma cases in the United States are associated with gas stoves. Researchers said that is as toxic as second-hand smoke.

But multiple factors could contribute to asthma cases, including whether a kitchen lacks a range hood above the gas stove to vent pollution.

Children participating in the Canadian research were assessed for asthma when they were three years old and again at age five.

The researchers are trying to determine whether genetic factors make some children more vulnerable to asthma through exposure to pollutants produced by gas stoves.

"We're looking for gene-environment interaction so we can actually answer those important questions," Subbarao said.

Dr. Theo Moraes, another study co-author and head of the division of respiratory medicine at SickKids Hospital in Toronto, said that among the entire cohort of children, a statistical difference in asthma is only seen at age three, not age five, for those living with gas stoves versus electric stoves.

SHOULD YOU DITCH YOUR GAS STOVE?

Michael Brauer, a CHILD investigator and professor at the University of British Columbia's School of Population and Public Health, co-wrote a commentary in the Lancet in 1996 about gas stoves and respiratory health. But he said that despite much more research into that topic since then, the overall evidence showing a definitive link remains "murky."

Brauer said much of the buzz around gas stoves may be linked to their association with climate change and that may be a better reason to stop using the appliances, which are connected to a supply system that leaks tiny amounts of the greenhouse gas methane.

"If you have the resources, there are several reasons to get rid of a gas stove," said Brauer, who was not involved in the research.

HOW COULD ANY NEGATIVE EFFECTS OF A GAS STOVE BE PREVENTED?

"Everybody needs to pay more attention to ventilation," said Jeff Brook, who leads CHILD's physical environment component and is an associate professor at the University of Toronto's Dalla Lana School of Public Health.

Hood fans that ventilate fumes to the outside could be considered the most important appliance in a kitchen but often get "short shrift," said Brook, adding cheaper versions can be noisy so people tend not to use them.

Older gas stoves with a pilot light that stays on are a constant source of nitrogen oxides, even when they're off, but opening a window whenever possible is a good option in the absence of proper ventilation in the kitchen, said Brook, a co-author of the paper.

WHAT ARE THE ALTERNATIVES?

Pressure cookers, microwaves and electric stoves, including induction stoves, which cook food quickly, are options to gas stoves.

Dr. Melissa Lem, a Vancouver family physician and president of the Canadian Association of Physicians for the Environment, said that from her perspective as a parent, choosing an induction stove would be a better, more energy-efficient way to cook without the burning of fossil fuels.

Lem said some people are putting a portable induction cooktop on a cutting board they place on top of their gas stove as a more affordable way to stop cooking with gas.

This report by The Canadian Press was first published June 16, 2023.

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