Picking your nose could put you at risk of Alzheimer's and dementia

The findings are in line with previous research on the matter.

A study last year found that the leakage of a specific toxic compound in the bloodstream might be the fundamental cause of Alzheimer’s. The research team discovered that beta-amyloids form outside of the brain and are then pushed through the body's bloodstream via lipoproteins.

Professor James St John, Head of the Clem Jones Center for Neurobiology and Stem Cell Research, is a co-author of the new research he says is a world first.

"We're the first to show that Chlamydia pneumoniae can go directly up the nose and into the brain where it can set off pathologies that look like Alzheimer's disease," St John said. "We saw this happen in a mouse model, and the evidence is potentially scary for humans as well."

In mice, the researchers noticed that the olfactory nerve in the nose offers a short pathway to the brain, one which bypasses the blood-brain barrier. As such, viruses and bacteria use it as a direct route to the brain.

Now, the team just needs to prove that the same pathway exists in humans and can be used in the same fashion by nefarious viruses and bacteria.

Same in humans?

"We need to do this study in humans and confirm whether the same pathway operates in the same way. It's research that has been proposed by many people, but not yet completed. What we do know is that these same bacteria are present in humans, but we haven't worked out how they get there."

To lower the risk of developing late-onset Alzheimer's disease, St John recommends avoiding certain activities.

"Picking your nose and plucking the hairs from your nose are not a good idea," he said.

"We don't want to damage the inside of our nose and picking and plucking can do that. If you damage the lining of the nose, you can increase how many bacteria can go up into your brain."

He further recommends smell tests for those 60 years and older in order to diagnose Alzheimer's and dementia early.

"Once you get over 65 years old, your risk factor goes right up, but we're looking at other causes as well, because it's not just age—it is environmental exposure as well. And we think that bacteria and viruses are critical."