Archive for the ‘SENSES’ Category


Friday, October 3rd, 2014

person smelling flower image

Researchers in the US have found that olfactory dysfunction was better at predicting mortality than a diagnosis of heart failure, cancer or lung disease. Photo: Supplied

Smelly socks have never seemed so life-affirming. According to a study published in scientific journal PLOS One, olfactory dysfunction – a weakening sense of smell – is a strikingly good indicator of imminent death.

No, a bad sense of smell isn’t fatal – and it probably isn’t the symptom of some insidious illness. But based on this new study, it seems that our noses may act as canaries in the coalmines of our bodies.

When things are amiss, and systems are shutting down, our sense of smell might be one of the best outward indicators, the researchers suggest.

antique leather arm chair image

Aromatic? A vintage leather armchair.

Researchers in the US tested a nationally representative sample of 3005 men and women aged 57 to 85 on their ability to identify five smells: rose, leather, orange, fish and peppermint. The study appears online in PLOS One.

They controlled for many factors – age, sex, socioeconomic status, smoking, alcohol intake, education, body mass index, race, hypertension, diabetes, heart attack, emphysema, stroke and diet.

Five years later, the researchers found that 430 of the original participants had died.

Thirty-nine per cent of study subjects who failed a simple smelling test died within five years, compared with 19 per cent of those

with moderate smell loss and just 10 per cent of those with a healthy sense of smell, PLOS One reported.

Even when they adjusted their analysis to control for age, gender, socioeconomic status, race, and overall health, they found that those with mild to severe smell loss were more likely to die.

“We think loss of the sense of smell is like the canary in the coalmine,” said the study’s lead author Jayant Pinto, an associate professor of surgery at the University of Chicago.

“It doesn’t directly cause death, but it’s a harbinger, an early warning, that something has gone badly wrong, that damage has been done.

“Our findings could provide a useful clinical test, a quick and inexpensive way to identify patients most at risk.”

Australian olfactory expert, James St John from Griffith University, told ABC radio’s PM program that he thought the study drew some very interesting conclusions.

“It certainly says that the sense of smell is an early warning system. If you’ve got something wrong with it and you can’t find a reason, that might suggest there’s something else wrong with you.”

He said the results might prompt people to think more about smell as a measure of health.

“We don’t really think about the sense of smell as an indicator very much. I mean, [if] you lose your sight, you’d go to the doctor pretty much instantaneously. Hearing, too.”

It is true that there are some instances in which a weakened sense of smell could contribute to the risk of death. A decreased sense of smell leads to loss of appetite, which could be dangerous in someone whose health is on the decline. A poor sense of smell also leaves the elderly vulnerable to risks such as gas leaks.

But because this study did not track down the exact cause of death of each individual, the researchers cannot make these kind of connections. And it’s more likely that the subjects’ sense of smell was just an indicator of declining health.

Researchers said olfactory dysfunction was better at predicting mortality than a diagnosis of heart failure, cancer or lung disease.

Dr St John said he hoped people would start taking more notice of their olfactory senses in Australia.

“It’s one of the more minor of the senses and we notice it most when we have a very bad nasal infection, a cold, we get a blocked nose.

“Maybe now, people should start thinking a bit more about it because it [could indicate] if you have a permanent loss or ongoing loss, that there’s something else wrong with you.”

Professor Pinto said he hoped the findings would cause people to rethink just how important their sense of smell is, especially since testing for olfactory loss is simple and cheap.

“Sense of smell is an under-appreciated sense,” he said. “It’s not something that’s in the medical consciousness or even the public consciousness.”

Washington Post, New York Times, AFP 

Henry Sapiecha