Study: A weakened sense of smell may be an early indicator of serious diseases

International experts have revealed that loss of the sense of smell has become an important sign that can point to a wide range of illnesses and may even serve as an early indicator of serious neurological and physical diseases.

This study was conducted by researchers from the University of East Anglia in Norwich, England; the Technical University of Dresden in Germany; the Monell Chemical Senses Center in the United States; the Smell Test charity; and the Department of Computer Science at University College London.

Estimates indicate that disorders of the sense of smell affect around one fifth of the population, with higher prevalence among adults over the age of 60 and among men.

Experts emphasized that the medical community has largely overlooked these disorders despite their association with more than 130 diseases, noting that they are more common than severe hearing loss and blindness.

Chronic sinusitis is the most common cause of loss of smell and may result from airway obstruction due to asthma, allergies, or cystic fibrosis.

Researchers explained that loss of smell may be an early sign of serious conditions such as dementia, Parkinson’s disease, and cardiovascular diseases.

The study confirmed that loss of smell can be among the earliest indicators of dementia, as harmful protein buildup appears in the part of the brain responsible for olfaction. Other studies have shown that impaired smell may emerge up to five years before the onset of movement difficulties associated with Parkinson’s disease in 90 percent of patients.

Experts added that loss of smell is linked to an increased risk of stroke and heart failure in otherwise healthy adults. It may also contribute to household accidents and foodborne illnesses due to the inability to detect gas, fire, smoke, or spoiled food.

The scientific review, published in the journal Clinical Otolaryngology, found that people with loss of smell often experience eating disorders, social isolation, anxiety, and depression. They also tend to follow a less varied diet that is higher in fat and sugar.

Finally, the experts called for integrating smell testing into routine medical practice, training healthcare professionals to use it, and developing and implementing public health and educational policies focused on the sense of smell across society.