Aging & Longevity
Older People Who Cannot
Distinguish Smells Likely to Die Before Those Who Can
After first test, 39
percent who failed died within five years
Oct. 1, 2014 Here is a
smell test senior citizens dont want to fail. Those who did the worst
in this study of older people trying to identify scents died off the
fastest. The researchers now say it may predict which older
people are most at risk of dying.
A large nationally
representative sample of men and women ages 57 to 85 were part of the
National Social Life, Health and Aging Project (NSHAP). The researchers
first surveyed 3,000 participants in 2005-06, assessing their
ability to identify five distinct common odors, one at a time, from a
set of four choices. The five odors, in order of increasing difficulty,
were peppermint, fish, orange, rose and leather.
In 2010-11 the research
team checked to see which participants were still living. During that
five-year gap, 430 (12.5%) of the original 3005 study subjects had died,
while 2,565 were still alive.
What caught their
attention was that thirty-nine percent of the subjects who failed the
smelling test in the first test had died before the second survey.
interest really peaked when they compared that death rate to the number
of deaths in among those more successful in the test. They found that 19
percent of those with moderate smell loss had died and just 10 percent
of those with a healthy sense of smell.
For those already at
high risk, lacking a sense of smell more than doubled the probability of
death, according to the report published today in the journal PLOS ONE
by Jayant M. Pinto, MD, and colleagues from The University of Chicago.
When the researchers
adjusted for demographic variables, such as age, gender, socioeconomic
status (as measured by education or assets), overall health, and race,
they concluded that those with greater smell loss when first tested were
substantially more likely to have died five years later.
Precisely how smell loss
contributes to mortality is unclear, but olfactory dysfunction was
better at predicting mortality than a diagnosis of heart failure, cancer
or lung disease. Only severe liver damage was a more powerful predictor
"We think loss of the
sense of smell is like the canary in the coal mine," said the study's
lead author Pinto, who is associate professor of surgery at the
University of Chicago.
"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."
Funding for the study
was from The National Institutes of Health, including the National
Institute on Aging, the Office of Women's Health Research, the Office of
AIDS Research, and the Office of Behavioral and Social Sciences
Research. Support was also provided by the National Institute on Aging,
the McHugh Otolaryngology Research Fund, the American Geriatrics
Society, The Center on the Demography and Economics of Aging, a Mellon
Foundation Social Sciences Dissertation-Year Fellowship, and the
Institute of Translational Medicine at The University of Chicago.).