People with poor oral hygiene or gum disease could be at a greater risk of developing Alzheimer’s disease, according to new university research.
The study, carried out by researchers at the University of Central Lancashire’s school of medicine and dentistry, examined brain samples donated by ten patients without dementia and ten patients suffering from dementia.
The team found that brains of deceased dementia patients were found to contain signs of Porphyromonas gingivalis, the bug responsible for unhealthy gums.
Scientists believe when the bacteria reach the brain they trigger an immune response that can lead to the death of neurons.
The process could help drive the changes that are typical of Alzheimer’s disease, causing symptoms of confusion and memory loss.
Professor StJohn Crean, dean of the school of medicine and dentistry at the university, said: “This new research indicates a possible association between gum disease and individuals who may be susceptible to developing Alzheimer’s disease, if exposed to the appropriate trigger.
“Research currently under way at UCLan is playing an active role in exploring this link, but it remains to be proven whether poor dental hygiene can lead to dementia in healthy people, which obviously could have significant implications for the population as a whole. It is also likely that these bacteria could make the existing disease condition worse.”
The findings are reported in the Journal of Alzheimer’s Disease. More recent work by the team has confirmed in animals that P gingivalis in the mouth finds its way to the brain once gum disease becomes established.
Lead researcher Dr Sim Singhrao said: “We are working on the theory that when the brain is repeatedly exposed to bacteria and/or their debris from our gums, subsequent immune responses may lead to nerve cell death and possibly memory loss.
“Continued visits to dental hygiene professionals throughout one’s life may be more important than currently envisaged with inferences for health outside of the mouth only.”
Rachel Waddington, a professor in oral biochemistry at Cardiff University said that poor oral hygiene had been linked to a number of serious health conditions, including dementia.
She said: “The bacteria in periodontal disease has been linked with quite a number of diseases and health conditions, including heart attacks, pre-eclampsia and Alzheimer’s.
“What happens is that the bacteria gets into the blood stream and then gets distributed around the body.
“I don’t think we publicise the effects of poor oral hygiene enough – it’s about more than losing your teeth, it can cause a whole host of conditions and lead to poor health.”
Dr Simon Ridley, head of research at Alzheimer’s Research UK, said:“This is an early study with a very small number of samples that observed bacteria linked to gum disease in the brains of people with Alzheimer’s.
“We don’t know whether the presence of these bacteria in the brain contributes to the disease and further research will be needed to investigate this. It is possible that reduced oral hygiene and therefore P gingivalis infection could be a consequence of later stage Alzheimer’s, rather than a cause.
“Other studies have suggested that infections, including oral infections, could be linked to Alzheimer’s and there is ongoing research in this area. It will be important for future studies to consider looking back at dental records, to correlate these kinds of observations with the level of oral hygiene during life.
“We know that there are likely to be many risk factors for Alzheimer’s and we need to investigate these in more detail to help develop new prevention or treatments.
“While a causal link between poor oral health and Alzheimer’s is still unclear, people who are worried about their dental health should still visit their dentist regularly.”