Could fading sense of smell mean death is closer? A new study says it is, and people in their 40s and 50s, suffering from impaired sense of smell are more likely to die within 10 years.
The study also ruled out dementia, previously linked to poor sense of smell, as the cause behind it.
"The sense of smell seems to be a good indicator of aging brain health," Jonas Olofsson, an associate professor of psychology at Stockholm University, said. He is the coauthor of the study published in the Journal of the American Geriatrics Society on March 22.
The study noted that about 70 percent of people in their middle age and older are suffering from impaired sense of smell, a condition called anosmia, while only 15 percent or lesser of young people suffered from the condition.
Dementia had previously been associated with the poor sense of smell, but "[it] could not explain any part of the link between smell loss and mortality risk," Olofsson said.
Smell Test Performance
For 10 years, the researchers studied some 1,800 adults aged 40 to 90 over a range of variables such as initial smell tests, health conditions, and mental health. Over that period, around 400 of the participants died.
The results indicated that there is a correlation between lower scores on olfactory assessments and the increased likelihood of death.
Loss of sense of smell could predict the increased risks of death, Olofsson said.
"This effect persisted after we adjusted for education level, health status, and mental functioning, variables that might otherwise determine how well we age," Olofsson observed.
The researchers, however, could not directly connect an impaired olfactory assessment to an early death.
Poor Sense Of Smell And Brain Processes
Although the loss of sense of smell does not mean death, it could be an early warning that some damage may have been done. Theories had it that an impaired sense of smell is an indicator of less regeneration of cells in the body.
Olofsson said several factors could affect the sense of smell.
For one, it could be environmental agents, such as viruses, prions, toxins, and pollution that affect olfactory nerve.
"Second, the olfactory system might be particularly sensitive to changes in recovery from environmental insult through processes ... that are reduced at older ages."
He said to determine the biological processes linking the loss of sense of smell to death requires neurophysiological study and data on the cause of death.
"These results contribute to the growing evidence that olfactory assessments might provide a unique window into brain aging processes," Olofsson said.
This should not be a cause for concern, however.
Bad cold, common allergies, and sinus problem can also lead to poor sense of smell. If the symptom persists, the best way is to see a doctor.