Imagine smelling something that is not there. Now imagine if these smells were always around, persisting through everyday life without any apparent reason. These ‘phantom odours’ occur when someone smells something, but there is nothing in the environment that corresponds to those, often unpleasant, odours. Though it may seem like a minor irritation, a persistent problem with smells can come with some risks and indicate other health issues, according to a new study published in the Journal of the American Medical Association (JAMA) titled “Otolaryngology-Head and Neck Surgery”.
The study reports that one in fifteen people (or 6.5%), from more than 7,400 people over 40 years old, smelt phantom odours. Researchers from the National Institute on Deafness and Other Communication Disorders (NIDCD) looked at National Health and Nutrition Examination Survey (NHANES) records between 2011 and 2014. The study was led by Kathleen Bainbridge, of the epidemiology and biostatistics programme at the NIDCD.
“Problems with the sense of smell are often overlooked, despite their importance. 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,” said Judith A Cooper, acting director of the NIDCD. Dr Donald Leopold, one of the study’s authors and clinical professor in the department of surgery at University of Vermont Medical Center, Burlington, added that patients, who perceive strong phantom odours, often, have a miserable quality of life and, sometimes, cannot maintain a healthy weight.
Phantom smells are especially problematic for those who work in places that rely on their sense of smell, such as those in the food and service industries. To explore the correlation between phantom odours and participant characteristics, the researchers looked at participants’ age, sex, education level, race/ethnicity, socio-economic status, certain health habits and general health status.
The study found that the ability to identify odours tends to decrease with age. However, phantom odour perception seems to increase with age. A previous study conducted in a community in Sweden, showed that 4.9% of people over the age of 60 experience phantom odours, with a much higher prevalence in women than men. The new study has also found a similar prevalence in the over 60 age group; but, after further examination, there is an even higher prevalence in ages between 40 and 60. A particularly striking finding is that twice as many women as men reported phantom odours; this was more so for females under the age of 60.
Earlier research suggested that women are generally better than men at naming odours and are, more often, negatively affected by odours around them. They may also have a heightened sense of smell and are more likely to report a problem with phantom smells. The new study points to other risk factors for the onset of phantom odours, such as head injury, dry mouth, poor overall health and low socio-economic status. Researchers have hypothesised that people with lower socio-economic status may more commonly be exposed to environmental pollutants and toxins, or have health conditions that contribute to phantom odours, either directly or because of medications needed to treat their health conditions.
After analysis of the data, this new study has shed further light on the problem of phantom smells. Yet, it has not been able to provide a clear answer about why it occurs. “The causes of phantom odor perception are not understood. The condition could be related to overactive odor sensing cells in the nasal cavity or perhaps a malfunction in the part of the brain that understands odor signals. A good first step in understanding any medical condition is a clear description of the phenomenon. From there, other researchers may form ideas about where to look further for possible causes and ultimately for ways to prevent or treat the condition,” said Dr Bainbridge.
