Picking your nose is unsightly — but it may also raise your risk of dementia.
Scientists have called for more research into the link between the bad habit and Alzheimer’s disease.
Writing in a medical journal last month, they admitted that studies on the topic were ‘scarce’.
But the research that has been done indicates nose picking is ‘a significant risk factor’, they added.
The theory is that germs are transferred from the fingers to the nose where they travel to the brain and cause inflammation.
The memory-robbing disease is characterised by a build up of harmful protein deposits in the brain known as amyloid proteins. When the brain becomes inflamed, it expresses an amyloid precursor protein that can build up into clumps and affect healthy brain cells
Over time, this inflammation damages brain cells leading to the symptoms associated with dementia.
Nose picking may also damage the lining of the nasal wall, making it easier for micro-organisms to enter the blood stream and trigger an infection and cause inflammation.
The calls for more research were made in a letter published in the American Journal of the Medical Sciences.
They cited ten studies showing a potential association, including one backed by the National Institutes of Health (NIH) from last year which also warned of the potential link.
Writing in the letter, they said: ‘Several pathogens, including those that invade the brain via the nasal epithelium… have been linked to Alzheimer’s disease and have been isolated during post-mortem analysis.
‘In conclusion, these studies show that nose picking is a significant risk factor and has a part in the progression of Alzheimer’s disease.
‘We propose more investigation to understand the association of nose picking with Alzheimer’s disease in the form of case-control studies with larger sample populations.’
Pathogens thought to cause the amyloid plaques include the herpes virus, coronavirus, the bacteria behind pneumonia and the fungus Candida albicans.
Nearly every American picks their nose, studies suggest – with many doing it four times a day on average
These can travel along the olfactory nerve, linking the nose and the brain, to the olfactory bulb, a small area at the bottom of the brain linked to smell, and cause an infection.
The letter was by scientists at the Services Institute of Medical Sciences in Pakistan and the Hamad Medical Corporation in Qatar.
It follows research from other scientists including a team in Australia, who also warned of a link between nose picking and Alzheimer’s.
They called for simple intervention measures like regular hand washing to reduce the risk posed by nose picking — calling this an ‘easy prevention step’ for the disease.
‘One of the lessons learned from Covid is the value of hand hygiene through frequent hand washing and the use of hand sanitizers,’ they wrote.
‘We suggest these routine hygienic procedures be mandatory routine procedures for the incurable nose-picker.’
Alzheimer’s disease is the most common form of dementia globally and afflicts an estimated 6.7 million Americans 65 and older.
The disease’s exact origins are still being studied, but scientists have pointed to a buildup of amyloid plaques and tangles in the brain of a protein called tau.
Other suggestions include that it may be linked to damage and scarring on blood vessels within the brain, which could reduce blood flow and trigger tiny unnoticed strokes that may cause the disease.
Surveys suggest that nearly every American picks their nose daily, removing dried mucus from the cavity four times a day on average.
