Phantom smells may be more common than thought, study finds

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Phantom smells can be a sign of a serious health problem, but until now it’s not been known how many people experience them.

A new study finds that 1 in 15 Americans over the age of 40 detect strange odors like burning hair or rotting food when nothing is actually there. The study, published Thursday in JAMA Otolaryngology-Head and Neck Surgery, is the first in the U.S. to estimate how common the phenomenon is in nationally representative data.

“Problems with the sense of smell are often overlooked, despite their importance,” said Judith A. Cooper, acting director of the the National Institute on Deafness and Communication Disorders, part of the National Institutes of Health. “They can have a big impact on appetite, food preferences and the ability to smell danger signals such as fire, gas leaks and spoiled food.”

Researchers used data from 7,417 participants over 40 years of age from the 2011-2014 National Health and Nutrition Examination Survey. The data was collected by the National Center for Health Statistics, which is part of the Centers for Disease Control and Prevention.

Millions of Americans experience some type of olfactory problem, including conditions such as anosmia, or the inability to smell; hyposmia, a decreased ability to smell; and parosmia, a distorted perception of smell. Many people with smelling disorders also have issues with taste, because smell and taste are inextricably linked.

“Phantom smells are not known to be a sign of disease,” said epidemiologist and lead author Kathleen Bainbridge of the communications disorders institute. “However, we found phantom odors to be more common among people who have fair or poor health.”

Brief episodes of phantosmia, or phantom smells, can be triggered by temporal lobe seizures, epilepsy or head trauma. Phantosmia is also associated with Alzheimer’s and occasionally with the onset of a migraine.