Dead Men Smell No Tales
An astonishing new report has concluded that elderly people who lose their sense of smell are not long for this earth. The National Social Life, Health and Aging Project [NSHAP] began in the mid-2000s. It is an ongoing study of more than 3,000 older Americans (57-85 years of age in 2005). Five years later, investigators looked at this group again, looking for any signs that might have been used to predict the onset of death.
Doctors use numerous “biomarkers” to detect disease, or the risk of disease. A biomarker is usually a substance that can be isolated from the blood, urine, or other body fluids. Biomarkers are usually proteins, although not necessarily. They provide useful information about current and future health. The hemoglobin A1c test, for example, evaluates a protein that signals poor blood sugar control. It for can be used to detect high blood sugar and monitor its control. If blood sugar levels remain high or otherwise out of control, doctors can predict with some accuracy how this may impact a patient’s health and prognosis.
Investigators are always on the lookout for new biomarkers that may signal pending disease, or even death. But not all such signposts are proteins circulating in the bloodstream. The research confirms what has been suspected for some time: The loss of the sense of smell (olfactory function) among the elderly is closely associated with pending death.
Loss of the sense of smell is not uncommon among the elderly and frail. The researchers discovered that people suffering from a total loss of the sense of smell are three times more likely to die than similarly-aged people whose sense of smell is still intact. People with diminished sense of smell are also more likely to die, in a “dose-dependent” fashion. This means that the worse the sense of smell, the more likely an individual is to die soon. These relationships remained firmly in place even after investigators allowed for a number of possible confounding factors, such as nutrition, mental health, smoking, or alcohol abuse.
“Olfactory function is thus one of the strongest predictors of 5-year mortality and may serve as a bellwether for slowed cellular regeneration or as a marker of cumulative toxic environmental exposures,” investigators concluded.
Pinto JM1, Wroblewski KE2, Kern DW3, Schumm LP2, McClintock MK3. Olfactory dysfunction predicts 5-year mortality in older adults. PLoS One. 2014 Oct 1;9(10):e107541. doi: 10.1371/journal.pone.0107541. eCollection 2014.