Here's a part of ageing that really stinks

Unpleasant phantom odours haunt many older Americans, a new study finds.

Of more than 7 400 people over age 40 who took part in a federal health survey, 6.5% said they experience nasty odours – such as burning hair or the reek of an ashtray – from nowhere. That's one in 15 people.

As folks age, their ability to identify odours tends to decrease, but their detection of phantom odours increases. Why this happens is a mystery, but smelling something that isn't really there can be life-changing, the researchers said.

"Problems with the sense of smell are often overlooked, despite their importance. They can have a big impact on appetite, food preferences, and the ability to smell danger signals such as fire, gas leaks and spoiled food," said Judith Cooper, acting director of the US National Institute on Deafness and Other Communication Disorders (NIDCD) that led the study.

Phantom odours

Lead researcher Kathleen Bainbridge said overactive odour-sensing cells in the nasal cavity or a malfunction in the brain area that understands odour signals may be involved. The new study lays the groundwork for further research.

"A good first step in understanding any medical condition is a clear description of the phenomenon. From there, other researchers may form ideas about where to look further for possible causes and ultimately for ways to prevent or treat the condition," Bainbridge said in an institute news release. She is an NIDCD epidemiologist.

Study co-author Dr Donald Leopold is a clinical professor of surgery at the University of Vermont Medical Center in Burlington. He said many people who experience strong phantom odours have a poor quality of life. They may also have trouble maintaining a healthy weight.

The new research follows a Swedish study that reported 4.9% of people older than 60 experienced phantom odours. It said the rate was higher among women than men.

The study was published in the journal JAMA Otolaryngology-Head and Neck Surgery.

More likely in women

This new study found a similar rate among Americans over 60, but an even higher rate among those between 40 and 60. Roughly twice as many women as men reported experiencing phantom odours, and the gender gap was greatest in the younger group, the NIDCD study found.

Besides gender, other risk factors for experiencing phantom odours include head injury, dry mouth, poor overall health, and being poor, the researchers said.

They said poor people may have greater exposure to environmental pollutants and toxins, or have health conditions that contribute to the problem, either directly or because of medications they take.

^{Image credit: iStock}