Medical journal recommends scent ban but science not exact
Canada’s top medical journal says all hospitals should ban fragrances, renewing the debate over how far society should go to accommodate those with “scent sensitivities” in the face of uncertain science.
An editorial in this week’s Canadian Medical Association Journal argues for a ban on artificially fragranced products in hospitals, saying they can cause “unintended harm” to vulnerable patients, including those with asthma.
“There is little justification for continuing to tolerate artificial scents in our hospitals,” write the authors, two Montreal doctors.
Four years ago, however, the same journal reported scent- free policies are based on “fuzzy and inconclusive” science.
Pamela Dalton, a scientist with Monell Chemical Senses Center in Philadelphia, says the data used to support scent- free policies is usually based on how many people find odours intolerable, or how many say they experience symptoms in response to odours, particularly people with asthma or other respiratory diseases.
“And in those populations, we don’t really understand, what are the drivers of those effects.”
Dalton isn’t saying they don’t occur, or that people cannot experience true, physiological reactions from exposure to perfumes, scented deodorant, lotions, colognes and aftershave. However, she says a strong psychological component is likely at play, as well.
In one small study, her team had people with asthma smell the same odour — a pure rose compound that has never been found to be irritating, at any concentration. Half were told the scent could make some people with asthma feel better; the other half told it made asthma worse.
Those who were told the odour was harmful not only reported more problems breathing, the researchers saw an actual change in their airway inflammation, based purely on the suggestion.
According to the Canadian Lung Association, 15 to 20 per cent of the population suffers from asthma, bronchitis, emphysema or other breathing problem. About a third of those with asthma say their condition is made worse by exposure to scents worn by others.
Scent sensitive people have reported reactions such as headaches, dizziness, wheezing, nausea, fatigue, confusion and anxiety.
Dr. Ken Flegel, co- author of this week’s editorial, says evidence is growing that asthma, in some cases, is aggravated primarily by artificial scents.
Instead, many may be so- called irritant, or toxic asthma. Researchers have identified receptors in the sensory nerves in the nose and airways that respond to certain fragrances, triggering an electrical signal that can cause the muscles around the airways to constrict.
“We know enough now to take precautionary measures in our hospitals,” Flegel and his coauthor, respirologist Dr. James Martin, chair of the department of medicine at McGill University, write in the CMAJ.