A Canadian study of more than 2000 babies suggests those brought up in households that used more cleaning products were at significantly greater risk of getting asthma by the age of three.
This has prompted the researchers to call for better regulation of cleaning supplies, including a requirement that manufacturers list chemical ingredients on packaging and that testing for adverse health effects is done before they are sold.
While the study shows a link, it can’t prove cleaning agents are responsible for asthma. But the authors say there is strong evidence from other studies that cleaning agents cause asthma in adolescents and adults.
They also think it’s plausible that long-term exposure to the products causes inflammation and narrowing of the airways. Many cleaning agents contain volatile organic compounds, chemicals the American Lung Association says are linked to respiratory problems and should be avoided.
In their study, published in the Canadian Medical Association Journal, the team used data from the Canadian Healthy Infant Longitudinal Development (CHILD) study, collected between 2008 and 2015, to score how often cleaning products were used in the home when a child was three to four months old.
Then they fast-forwarded to when the child was three to see how many had been diagnosed with asthma or had recurrent wheeze, a whistling sound during exhalation that’s a sign of narrowed airways.
They found children in homes with the most frequent use of cleaning products had 37% higher odds of an asthma diagnosis and 35% higher odds of reporting wheeze.
Products with the strongest link to asthma were scented, spray-on products that produce fine liquid droplets called aerosols.
“We think that is because it helps with facilitating the exposure to a person’s lungs,” says senior author Jaclyn Parks, from Simon Fraser University in Vancouver. “It can then settle on dust which you inhale later, or the actual spraying of a product can be entering your lungs then.”
Infants may be at particular risk, say the authors, because they have a higher breathing rate and so take more in. They are also lower to the ground.
“[S]tudies have found that the chemicals that you can detect in the air after… a cleaning act stays concentrated for a number of hours and that it’s actually more concentrated at, say, a two-foot level than a five-foot level,” says Parks.
“That seems to be where infants hang out a lot.”
In a related commentary, Elissa Abrams from the University of Manitoba, Canada, says there is no requirement for manufacturers in the US and Canada to list all the ingredients in household cleaning products.
“[E]ven products labelled as ‘environmentally friendly’ or ‘green’ may contain harmful substances, as such claims are largely unregulated,” she writes.
It’s an issue that extends beyond North America.
A 2015 study found fragranced consumer products – including cleaning products and air fresheners – contained an average of 15 volatile organic compounds each. Yet a recent analysis found “no jurisdiction in the world requires full disclosure of all ingredients contained in a fragrance mixture”.
The lead researcher for the new study, Tim Takaro from Simon Fraser University, says Europe may offer a model for how to regulate the products. Their REACH regulation (Registration, Evaluation, Authorisation and restriction of Chemicals) mandates chemicals produced above certain quantities have proven safe exposure levels.
But consumers can’t push back unless they know what’s in the bottle.
“If people can be more aware about what is in their products, they might be asking more questions and asking for more clear information about what exactly they’re buying,” says Parks.
But Parks also thinks a shift in our cleaning culture – including our penchant for artificial fragrances – might be in order.
“We need to make a conscious effort to question what we really define as ‘clean’ when it comes to pollutants in the air” she says.
“So, if people want to say ‘what does a healthy home smell like?’ – nothing.”
Paul Biegler is a philosopher, physician and Adjunct Research Fellow in Bioethics at Monash University. He received the 2012 Australasian Association of Philosophy Media Prize and his book The Ethical Treatment of Depression (MIT Press 2011) won the Australian Museum Eureka Prize for Research in Ethics.
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