Smell could predict impending frailty and death

By Alice Clifford via SWNS

Noses could predict impending frailty and death, a new study reveals.

The research links a keen sense of smell to people being fitter and healthier while finding smelling difficult was associated with declining health.

These new results suggest that smell loss could be a useful indicator of overall health in older people.

Adding smell tests to routine screenings could help identify someone’s risk of unhealthy aging, and act as a tipoff to whether additional tests are needed.

Dr. Nicholas Rowan, associate professor of head and neck surgery from Johns Hopkins University, and study author, said: “We already do tests to assess how well we can see or hear, and it’s just as easy to conduct a simple smell test that takes only minutes, which could potentially be used as a valuable tool to assess the risk of frailty or unhealthy aging.

“For example, if someone flunks a smell test then maybe this patient needs to improve their nutrition or undergo a more detailed neurological or medical workup.”

The study builds on previous research that shows a drop in one’s ability to smell is a common early sign of brain-linked cognitive decline.

However, the findings suggest that the connection to frailty is likely not just in the brain but also in the nose itself.

The researchers used data from nearly 1,200 older adults.

They studied the link between a person’s frailty and their ability to smell.

Frailty is an age-related syndrome of physical decline.

They tested participants' capability to detect an odor’s presence, and their ability to detect and name an odor.

These measures of smell are called olfactory sensitivity and olfactory identification, respectively.

Olfactory identification is a central measure of smell function and relies on the brain to help work out what the smell is.

This suggests that neurological function may help to explain the relationship between smell and frailty.

Dr. Rowan said: “We use our sense of smell to identify the threat of a fire or to enjoy the fragrance of flowers on a spring day. But just like vision and hearing, this sense weakens as we age.

“We found that both impaired olfactory identification and sensitivity functions are associated with frailty, which is interesting because it shows that it’s not just your aging brain at work here, but it may also be something peripheral, like something at the level of your nose that is able to predict our impending frailty and death.”

However, the relationship between these unique sensory losses with unhealthy aging is unclear.

Common consequences of smell loss include a loss of appetite, difficulty monitoring personal hygiene, depression and an inability to detect toxic fumes.

For older adults, it can also lead to weight loss, malnutrition, weakness, inadequate personal care and even potential injuries caused by gas leaks or fires.

In the US, the population of older adults is estimated to double in the next three decades.

This has led to a push in research to try discover which people are most likely to experience frailty and earlier death.

The team used a standard assessment of frailty called a Physical Frailty Phenotype score.

The test looked at five markers. These were weight loss, exhaustion, weakness, slow walking speed and low physical activity.

To investigate the relationship between frailty and smell loss, they analyzed data from 1,160 older adults.

They were all enrolled in the National Social Life, Health and Aging Project between 2015 and 2016.

The average age of the participants was 76, with 55.7 percent being women.

Each person was exposed to five scents to measure their ability to detect and name a smell.

They were also given six scents to measure how well they could detect the presence of an odor.

These results were then matched with the subject’s frailty score.

For every one-point increase in both smelling identification and sensitivity, there was a significant and meaningful drop in their frailty.

The study thus shows that improvements in smell are linked to better health and resilience.

Contrastingly, a poor sense of smell is associated with weakness and unhealthy aging.

These results are especially important in the setting of the COVID-19 pandemic, as many lost their sense of smell thanks to the virus.

Dr. Rowan said: “The really interesting question, though, is what happens to these novel relationships when you seek to treat the smell loss.”

The study was published in the Journal of Gerontology.