Imagine if a simple smell test could determine if you were going to die in the next five years. According to researchers from the University of Chicago, it turns out the nose knows, and your lack of smell more than doubles the probability you will die within the next five years. They studied the link between lack of sense of smell and death and published their findings in the journal PLOS ONE.

Between 2005 to 2006, researchers studied 3,000 men and women ages 57 to 85 and recorded how well their ability to identify five distinct common odors was. Each person was asked to identify one smell at a time from a set of four different choices, and as the test went on, it became increasingly difficult. At first, they were asked to identify the smell of peppermint, then fish, orange, rose, and lastly, leather.

In a second survey with the same participants, researchers asked the remaining who were living the same questions about their sense of smell. In the course of the five-year gap between surveys, 430 participants had died and 39 percent of them had also failed the smelling test the first time around. Those who had moderate smell loss made up 19 percent of the deceased while only 10 percent that died within the five years had a healthy sense of smell.

"We think loss of the sense of smell is like the canary in the coal mine," the study's lead author Jayant M. Pinto, associate professor of surgery at the University of Chicago, said in a press release. "It doesn't directly cause death, but it's a harbinger, an early warning system, that something has already 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."

Those with the greatest loss of smell were the most likely candidates for death within five years, and researchers aren’t even sure why the body works that way. The body’s olfactics, which is the sense of smell, may be dysfunctional because of dying sensory cells in the nostrils, but as of yet more research needs to be done to be sure.

Currently, loss of smell is better at predicting mortality than a diagnosis of heart failure, cancer, or lung disease. Smelling death really means to smell nothing at all.

Source: Pinto JM, Wroblewski KE, Kern DW, Schumm LP, and McClintock MK. Olfactory Dysfunction Predicts 5-Year Mortality in Older Adults. PLOS ONE. 2014.