A Decreased Sense Of Smell Could Predict An Increased Risk Of Mortality In Older Individuals

The inability to detect certain smells may indicate an early sign of mortality in older individuals, according to recent findings published in the journal Plos One.

"We think loss of the sense of smell is like the canary in the coal mine," said lead study author Jayant Pinto, an associate professor of surgery, in a news release. "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."

For the study, researchers from the National Social Life, Health and Aging Project at the University of Chicago, conducted the first in-home study of social relationships and health in a large, nationally representative sample of men and women aged 57 to 85.

All involved were examined based on their age, physical and mental health, as well as social and financial resources, educational and alcohol or substance abuse. 

Findings showed that as participants age, their ability to smell seemed to steadily decline. 

Estimates revealed that around 39 percent of those in the study who failed a smelling test also died during the study period, compared to 19 percent of those with moderate smell loss and 10 percent of those with a healthy sense of smell.

Furthermore,  64 percent of 57-year-olds correctly identified all of the smells in the tests. Yet by 85, only 25 percent did.

"This evolutionarily ancient special sense may signal a key mechanism that affects human longevity," added senior study author Martha McClintock.

However, researchers concluded that more studies will need to be conducted in order to determine just how smell loss contributes to mortality, overall.