Get a whiff of this: Losing your sense of smell predicts impending death better than heart failure, lung disease, and cancer, suggests a new study from the University of Chicago.
Researchers tested the smelling capabilities of 3,000 adults over age 57 and followed up 5 years later to see who was still alive. Those who had failed the test—about 4 percent of the population—were four times as likely to have died as people who could smell normally.
Not being able to smell was found to be a bigger risk factor for mortality than any known leading cause of death.
Here's the really bad news: Men are 30 to 40 percent more likely to lose their sniffing powers than women, says study author Jayant Pinto, M.D.
So how in the world does your sense of smell predict your risk of death? Pinto says he and the other researchers aren't sure yet, but they have a couple guesses.
Losing your ability to smell could be a sign that your body is no longer equipped to repair and regenerate cells, a normal part of the aging process that may ultimately lead to death, Pinto says. That's because the olfactory system—the body parts that enable you to take a whiff—depends on cell turnover more than any other sense.
Another possibility: The nerve responsible for smell is the only one directly connected to your brain that is also exposed to the environment, Pinto says. So if you encounter lots of pollutants, toxins, and germs over the course of your life, that could fatally damage your sense of smell—and the rest of your body.
Diminished smell is a normal part of getting older, just like hearing loss, Pinto says. Researchers don't know if the association between your nose and death holds true in younger people, but plan to study that next.
The classic sign that your sniffer is slipping is if everyone around you can sense an odor, like burning toast or rotting garbage, and you can't. If that regularly happens to you, don't freak out—but make an appointment with your doctor for a checkup, Pinto says.