Besides decreased mobility and ability to clean and bathe properly, there’s a good reason for that old person smell that everyone knows and hates—your sense of smell deteriorates as you get older. So even those who are blessed with a long-lasting schnoz simply might not be able to tell when their home starts reeking of cat urine.
Some people lose their sense of smell earlier than others, however, and certain pathologies can also lead to olfactory deterioration before its time. And according to a recent study from the University of Chicago, it can also predict death.
There are a lot of obvious physical abnormalities that can predict when a person is more likely to pass away in the coming years. Heart failure, cancer, and lung disease all come to mind; when one of those comes knocking, you can bet the Grim Reaper isn’t too far behind.
But believe it or not, losing your sense of smell should be much more troubling than any of those three.
“We think loss of the sense of smell is like the canary in the coal mine,” said the study’s lead author Jayant M. Pinto, an associate professor of surgery at the University of Chicago who specializes in the genetics and treatment of olfactory and sinus disease. “It doesn’t directly cause death, but it’s a harbinger—an early warning that something has gone badly wrong and that damage has been done. Our findings could provide a useful clinical test, a quick and inexpensive way to identify patients most at risk.”
The National Social Life, Health and Aging Project is a nationwide longitudinal study following a wide cross section of Americans ages 57 to 85.. Starting in 2005, the study tested 3,005 participants and followed up with them five years later.
In that first year, most everyone could correctly identify at least four of five smells presented to them. But 3.5 percent were considered “anosmic,” meaning they could identify just one of the five scents or even none.
And of those who had a broken schnoz, 39 percent of them died within the next five years.
When the researchers adjusted for demographic variables such as age, gender, socioeconomic status (as measured by education or assets), overall health and race, those with greater smell loss when first tested were substantially more likely to have died five years later. Even mild smell loss was associated with greater risk. Acute loss of smell was a better predictor of mortality than every other physical ailment recorded other than liver failure.
“Of all human senses,” Pinto said, “smell is the most undervalued and underappreciated—until it’s gone.”
Precisely how smell loss contributes to mortality is unclear. “Obviously, people don’t die just because their olfactory system is damaged,” said Martha K. McClintock, the David Lee Shillinglaw Distinguished Service Professor of Psychology.
Whatever the reasons, it’s a fascinating and unexpected result that leave you wondering why. Sounds like an excellent beginning to somebody’s PhD thesis.
The study, “Olfactory Dysfunction Predicts 5-year Mortality in Older Adults,” was published in the Proceedings of the National Academy of Sciences by McClintock, Pinto, Kristen E. Wroblewski, David W. Kern and L. Philip Schumm, all from UChicago. Linda Waite is the principal investigator of NSHAP, a transdisciplinary effort with experts in sociology, geriatrics, psychology, epidemiology, statistics, survey methodology, medicine and surgery collaborating to advance knowledge about aging.