Loss Of Smell May Be A Predictor Of Death

April Flowers for redOrbit.com – Your Universe Online
The older generation is a source of constant study for scientists seeking to understand why some of us live such long lives, and some of us die relatively early. Studies have found many predictors of death in the elderly, including broken hips, love handles and nocturia (frequent bedwetting). A new study from the University of Chicago has added loss of smell (olfaction) to that list.
The findings, published in PLOS ONE, reveal that not being able to identify scents is a strong predictor of death within five years. In fact, 39 percent of those who failed the simple smelling test died during the five year time period. For those with moderate smell loss, only 19 percent died, and for those with no smell loss, the death rate was only 10 percent.
The study, part of the National Social Life, Health and Aging Project (NSHAP), found that the dangers of losing your sense of smell are “robust,” more so than most chronic diseases. For example, olfactory dysfunction was found to be a better predictor of death than a diagnosis of heart failure, cancer or lung disease. Only severe liver damage was found to be a more powerful predictor, and for those already at high risk, losing their 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, MD, an associate professor of surgery at the University of Chicago who specializes in the genetics and treatment of olfactory and sinus disease, said in a recent 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.”
NSHAP, the first in-home study of social relationships and health in a large, nationally representative sample of men and women between ages 57 and 85, provided the data for the study. Between 2005 and 2006, professional survey teams from the National Opinion Research Center at the University of Chicago conducted the first wave of NSHAP. They used a well-validated test which measures the ability to identify five distinct common odors. The test was adapted for the by Martha McClintock, PhD, of the Institute for Mind and Biology at the University of Chicago.
According to Smitha Mundasad of BBC News, the five scents were peppermint, fish, orange, rose and leather encased on the tips of felt tip pens named Sniffin’Sticks. Each participant was asked to identify each smell from a set of four choices.

Image Above: Jayant Pinto, M.D., is shown with one of the Sniffin’ Sticks used to test a patient’s ability to identify scents for his research on olfactory dysfunction and aging. Credit: Robert Kozloff/The University of Chicago
The team discovered that 75 percent of the participants were classified as “normosmic,” or having a normal sense of smell — of those, 45.5 percent correctly identified five out of five, while 29 percent identified four out of five. Almost 20 percent of the total cohort were classified as “hyposomic,” getting three out of five correct.
The final 3.5 percent could only identify one scent or less, classifying them as “anosmic.”
The researchers adjusted their findings for demographic variables such as age, gender, socioeconomic status (as measured by education or assets), overall health and race. Despite this, those with the poorest sense of smell were still at the highest risk.
Prof Pinto added: “The sense of smell is a little underappreciated – it plays a very important part in everyday life. But we don’t want people to panic. A bad cold, allergies, and sinus problems, can all affect your sense of smell.”
“People shouldn’t be too worried, but if problems persist they should speak to their physicians. And perhaps this study shows we need to start paying more attention to sensory health overall.”
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