A new study reveals that a poor sense of smell could be a key indicator of one's life expectancy.

According to researchers, the detection of a weakening sense of smell in older adults could be predictor of an increased risk of death within five years.

The study, which tested 3,005 adults aged 57-85, revealed that 39 percent of subjects who failed a simple smelling test died within five years. Meanwhile, those with moderate smell loss had only a 19 percent death rate within five years, and subjects with a healthy sense of smell had a 10 percent chance of dying within that time.

"Compared to a person with a normal sense of smell, a person with an absent sense of smell has three times greater risk of dying within a five-year span," Dr. Jayant Pinto, the study's lead author, which was published on Wednesday in the science journal PLOS ONE.

"What this tells us is your sense of smell is a great indicator of your overall health," Pinto told Reuters.

Although a bad sense of smell should not be interpreted as an automatic death sentence, scientists say that it could be an outward indicator of declining heath. According to the study, a healthy olfactory system has the ability to regenerate stem cells. However, if the system is not functioning properly, then that could be a sign that the body is no longer able to repair itself, which could lead to serious health problems.

"It doesn't cause death, but it's an early warning that something has gone badly wrong," Pinto said.

Researchers conducted the smell test in 2005 using "Sniffin' Sticks," which required subjects to identify either the smell of peppermint, fish, orange, rose or leather.

Nearly 78 percent of those tested were classified as having normal sense of smell because they were able to identify at four to five of the scents. However, 20 percent got two or three of the scents correct, while the remaining 3.5 percent could only correctly identify one or none of the scents.

By 2011, 430 of the subjects, or 12.5 percent, had died, reports the Washington Post.

"Researchers conducted interviews to adjust for variables and risk factors, such as age, smoking, alcohol use, overall health and socioeconomic status. In the end, those with greater smell loss when first tested were substantially more likely to have died five years later," Reuters reported.