Dwindling sense of smell shows dying risk

Declining sense of smell can be a warning sign of premature death

02/10/2014

If older people suddenly lose their sense of smell, it can be a sign of a life-threatening illness. American researchers have found that there is an association between the dwindling ability to smell and an increased risk of dying. Their results were published by the scientists in the journal „PLOS ONE ".

A sense of smell could serve as a biomarker for diseases
Older people should not take the loss of their sense of smell lightly. Scientists led by Jayant Pinto of the University of Chicago, Illinois, have found that "people who suddenly can not smell anymore have an increased risk of dying". Thus, "odor tests could act as an early warning system for serious illnesses".

„The sense of smell, an ancient chemical system, is a strong biomarker because it is linked to various physiological processes“, the researchers report in the journal. They wanted to find out if an olfactory disorder can be a harbinger of an increased risk of dying. To do so, they looked at 3,005 US citizens aged 57 to 85, who sampled for the „National Social Life, Health and Aging Project“ (NSHAP) were selected. In 2005 and 2006, study participants had to identify five smells of increasing difficulty: peppermint, fish, orange, rose and leather. In 2010 and 2011, the researchers checked which of the subjects were still alive and who had already died.

As it turned out, a total of 430 of the 3,005 men and women (12 percent) were no longer alive. Particularly high was the proportion of the deceased (39 percent) in the group of study participants who performed very poorly in the odor test five years earlier. 19 percent of the subjects with a mild olfactory disorder had also died. By contrast, of the women and men who could identify all odors in the test, only ten percent within the five years gave their lives.

Dwindling sense of smell as an early warning system
„In a comprehensive model that also included important confounding factors, older adults without a sense of smell were more than three times more likely to die than those with a functioning sense of smell - higher than known and independent of the leading causes of death and the mechanisms: diet, cognitive function, mental health, smoking and alcohol abuse or infirmity“, the researchers write. The exact mechanism underlying this result is unclear. „We think that the loss of the sense of smell is a species of canary in the coal mine, "Pinto is quoted in a statement to the study. „He does not cause death directly, but he is a messenger, an early warning system, something has already gone wrong, damage has been done. "

Dwindling sense of smell may indicate Parkinson's
Thomas Hummel from the Technical University in Dresden talks to the news agency „dpa“ that the sense of smell declines in old age but also in general. In addition, about five percent of people anyway are not able to smell. He advises people who suddenly could not smell any more to see a doctor. Chronic sinusitis or craniocerebral trauma sometimes results in the loss of the sense of smell. In addition, it has been proven in other studies that the less sick a person is, the less present the ability to smell.

Researchers at the University of Dresden have examined about 400 Parkinson's patients for their sense of smell. It turned out that three-quarters of them had an olfactory disorder that did not occur due to age. (Ag)