London - If the aroma of coffee or the scent of picked flowers is not as appealing as it once was, it could be more than simply a loss of those momentary pleasures.
A failing sense of smell may be a sign of more serious problems, even that your life could be in danger.
Research has shown that people with the poorest sense of smell are more than twice as likely to die in the next four years as those with the keenest.
Importantly, the link with longevity holds firm even when a person’s known medical conditions and lifestyle were taken into account.
In other words it seems that a poor sense of smell seems to be an early warning of impending death.
The reason is still a mystery but it is possible that this is an indication of a serious, as yet undiagnosed, illness.
Or it may be that not being able to smell properly leaves people vulnerable to other risks, such as eating food which has gone off or not being able to smell a fire or gas leak until it is too late.
Doctors from Columbia University in New York asked 1 200 men and women to identify 40 scents which were each impregnated on a strip of paper and accompanied by four possible answers. The volunteers, who were aged 65-plus, scratched a strip to release the smell, sniffed it and said what they thought it was.
They gave detailed information about their health, including if they had high blood pressure, diabetes or cancer. The volunteers were also asked if they smoked or drank alcohol, and if they were depressed.
Anyone known to have dementia or Parkinson’s disease, which affect the sense of smell, was excluded. Over the next four years, 349 of the men and women died and analysis showed a clear link with the sense of smell.
Every wrongly identified scent raised the odds of an early death and those with the poorest results were two-and-a-half times as likely to die early as those who got the most answers right.
Researcher Davangere Devanand, a specialist in the mental health of the elderly, said one possible explanation is that a poor sense of smell leaves people in physical danger.
In the journal Annals of Neurology, he said it “may lead to unhealthy food choices or malnutrition or an increased risk of accidents”.
He added: “A disproportionate number of elderly die in accidental gas poisonings and explosions each year, some of which can be attributed to smell loss.”
Previous research has shown that people who have lost their sense of smell are twice as likely to have suffered a serious hazard linked to this, such as a kitchen fire or eating spoiled food.
Another possibility is that the health of the olfactory nerve is a sign of overall health. If it no longer functions well, the brain and body may be the same.
Finally, it may be that infections, poisons and pollutants which we breathe in damage our sense of smell before harming the brain and body.
Dr Devanand said research on younger groups was needed to see if their risks were similar to his study group.
Daily Mail