Khaberni - Loss of smell may be a sign of sickness, or risk of exposure to sickness, involving a range of diseases, prompting experts to call for the necessity of screening for smell disorders.
Loss of smell is associated with an increased risk of stroke and heart failure.
In a review by an international research team from the UK, Germany, and the USA, researchers found increasing evidence linking smell disorders with more than 130 neurological, physical, and genetic disorders, and that it is more prevalent than severe hearing loss and blindness.
Estimates suggest that conditions causing loss of smell - medically known as smell disorders - affect one fifth of the general population, with higher rates in adults over 60 years of age, and in men.
According to the "Daily Mail", researchers explained that the main cause is chronic sinusitis, which could be caused by conditions blocking the airways such as asthma, allergies, or cystic fibrosis.
Smell and COVID
While they said that loss of smell is not new in upper respiratory infections like influenza and rhinovirus, studies have shown it is 8 to 10 times more prevalent in COVID-19 patients.
Nevertheless, researchers also pointed out that there are also emerging evidence that loss of smell can be an early warning sign for many diseases, including dementia and Parkinson's disease, and worryingly, deadly heart diseases.
In the new review, experts noted that one possible explanation suggested is that harmful proteins in people with dementia may have begun accumulating in the part of the brain responsible for smell.
Parkinson's Disease
The experts also highlighted a study showing that loss of smell can appear up to 5 years before traditional motor difficulties in 90% of Parkinson's disease patients.
The research team included researchers from the University of East Anglia, University of London, the Technical University in Dresden, Germany, and the Monell Chemical Senses Center in the USA.
Risks associated with loss of smell
Worryingly, increasing evidence suggests that loss of smell is linked to an increased risk of stroke and heart failure in healthy adults before they are diagnosed with smell disorders.
The new review also highlighted research that found many who suffer from loss of smell worry about their safety, given their inability to detect gas, fire, and smoke, and their inability to notice spoiled food, which could lead to food poisoning.
Isolation and Depression
They added that other research has shown that loss of smell is linked to higher rates of eating disorders, social isolation, relationship difficulties, and anxiety and depression.
The researchers said, "There is increasing evidence that patients with loss of smell follow a diet that is less diverse, higher in calories, and high in fats and sugars."
In light of this increasing evidence, experts have called for screening to detect loss of smell and train medical specialists on it.
