Don't worry – Picking your nose doesn't cause Alzheimer's disease
It's been a rough week for nose-pickers around the world, with a torrent of news headlines loudly declaring "scary evidence" has been found showing Alzheimer's disease is linked with a bit of finger-based nasal exploration. Turns out this link comes from a deeply speculative press release and, according to several neuroscientists New Atlas contacted, is "extremely unlikely."
As with much science news these days the nose-picking story originated with a press release, in this case one from Australia's Griffith University published on Friday the 28th of October. The news was headlined "New research suggests nose picking could increase risk for Alzheimer’s and dementia," and it promoted a study published in the journal Scientific Reports.
The study, in mice, found that a bacterium called Chlamydia pneumoniae can infect parts of the brain when seeded in the animal's nose. Further, the study found when that particular bacterium crosses into the mouse brain it can trigger pathological changes that are similar to what is seen in Alzheimer's disease.
Essentially that's "the research" – and perhaps most unusually, the research is not particularly "new." The study was actually published 10 months ago, back in February. And when it was published it was accompanied by a press release declaring, "Bacteria in the nose may increase risk of Alzheimer’s disease."
So it seems reasonable to ask why a 10-month-old study is being promoted as "new research" with an entirely new conclusion suddenly suggesting nose picking could be associated with Alzheimer's risk?
To try and understand how this novel link to nose picking arose New Atlas spoke to Professor James St John, one of the co-authors on the study. St John said he felt that when the first news release was published earlier in the year the study was swamped by other stories at the time. And since the study was first published he has been contacted by a number of ear, nose and throat (ENT) specialists excited by the findings, urging him to further explore this relationship between nasal infections and dementia.
"It has to be investigated, they said," St John told New Atlas, referring to the feedback he received from ENT researchers regarding the study. "We've never thought of looking at the history of infections, or damage to the nose, and they're right. Since we put out the media release I've had so many people contacting me. One said, my spouse, she got Alzheimer's disease, and she had bad nasal infections, and she was picking her nose a lot at the time she first had symptoms, and things like that. So we're not sure, but we have to find out."
The nose-picking link that seems to be the focus of this new wave of media coverage stems from one small part of the study that found deliberate injuries to the mouse epithelium led to increased bacterial infiltration in the peripheral nerves and olfactory bulb. The nasal epithelium is the thin layer of tissue that lines the inside of the nose, and in the study the researchers used a chemical to damage that tissue as a model resembling "natural nasal injuries" in humans.
The hypothesis St John is presenting is that nose picking can cause similar damage to the lining of your nose, which could possibly lead to greater volumes of pathogens moving into the brain. And those pathogens in the brain can then trigger a cascade of events that leads to the development of Alzheimer's disease.
Of course, that leaves a key question – what kind of vigorous nose picking are we talking about here?
St John admits "gentle nose picking is probably not going to do that," but if you are picking your nose till it bleeds then maybe that is more of a problem.
New Atlas contacted a number of neuroscientists and dementia researchers to get their feedback on this potential association between nose picking and Alzheimer's disease. Several felt the suggestion was so ridiculous they preferred not to even be associated with this story, however, some researchers did offer measured responses to St John's hypothesis.
Bryce Vissel, a neuroscientist from the University of New South Wales, has a particular research focus on neurodegenerative disease. He says the core findings in St John's study are interesting. According to Vissel the idea that bacterial infections could play a role in dementia, and that those infections can move from the nose to the brain, are compelling areas of research, albeit still incredibly speculative. They are not mainstream views, said Vissel, but they are certainly topics many researchers are investigating.
Where Vissel struggles is with the hypothetical leap to nose picking as a plausible risk factor for Alzheimer's disease. He says there is no evidence to indicate this incredibly common human behavior plays a role in Alzheimer's.
"I have never heard of that, seen evidence for it, or got basis on which to make such a statement," Vissel said. "I would worry that people would interpret what they've said to have some fear around doing what humans have done for millennia. And I think that fear would be unwarranted based on this paper."
Nikki-Anne Wilson, a postdoctoral fellow at Neuroscience Research Australia, echoes Vissel's thoughts. She agrees there is growing evidence to indicate inflections could hypothetically play a role in certain neurodegenerative diseases, but it's a big leap to jump from the findings in this new study to the suggestion nose picking is a contributing factor to Alzheimer's.
"The suggestion that a disruption to nasal epithelium may increase the likelihood of such an infection is novel," said Wilson. "However, this animal study is far from causal evidence that nose picking will give you Alzheimer’s disease. We know there are many contributing factors to developing Alzheimer‘s occurring across the lifespan and it is extremely unlikely to be caused by a stray finger up one’s nose."
St John is the first to admit more research should be done and he is working on starting a large study next year looking at people in the early stages of late-onset Alzheimer's disease. The study will investigate participants' sense of smell, sample bacteria in their nose and track their medical histories for evidence of nasal infections.
In talking about this upcoming study St John made no mention of surveying nose picking as a risk factor for Alzheimer's. And considering prior research has found nose picking to be "an almost universal practice in adults," you'd probably be hard-pressed to find someone who admits they haven't ever slipped a sneaky finger up there for a quick clean up.
Ultimately, despite the hyperbolic news headlines from the past week, nose pickers should relax and not worry they are giving themselves dementia. Sure, maybe take it easy and be gentle when you are having a bit of a nasal excavation, but don't worry this extraordinarily common behavior is going to give you Alzheimer's disease.