Being unable to smell coffee in the morning could be a predictor of increased risk of death within five years, according to a recent study.

Researchers from the University of Chicago Medical Center found that olfactory dysfunction was better at predicting mortality than a diagnosis of heart failure, cancer or lung disease, Reuters reported. Only severe liver damage was a more powerful predictor of death. For those already at high risk, lacking a sense of smell more than doubled the probability of death.

"We think loss of the sense of smell is like the canary in the coal mine," Jayant M. Pinto, lead author of the study, said in a statement. "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, Pinto and his colleagues collected data from more than 3,000 people aged 57 to 85 years old. They measured the study participant's ability to identify five distinct common odors.

Thirty-nine percent of subjects who failed a simple smelling test died within five years. Those with moderate smell loss had a 19 percent death rate within five years and those deemed to have a healthy sense of smell only had a 10 percent death rate.

"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," Pinto told Reuters.

Age-related smell loss can have a substantial impact on lifestyle and wellbeing. As expected, performance on the scent test declined steadily with age; 64 percent of 57-year-olds correctly identified all five smells. That fell to 25 percent of 85-year-olds.

"Smells impact how foods taste. Many people with smell deficits lose the joy of eating. They make poor food choices, get less nutrition," Pinto said. "They can't tell when foods have spoiled or detect odors that signal danger, like a gas leak or smoke. They may not notice lapses in personal hygiene."

Precisely how smell loss contributes to mortality is unclear.

The research team, which includes biopsychologists, physicians, sociologists and statisticians, is considering several hypotheses.

The findings were published in the journal PLOS ONE.