The mouth is a route for bacteria to enter the bloodstream through the gums.
The study - led by the University of Birmingham in the UK and published in the Journal of Clinical Periodontology - provides further evidence of a link between oral health and chronic diseases, say the authors.
Senior author Iain Chapple, a professor in periodontology, says we should be aware that oral health is not just about teeth, and:
"The mouth is the doorway to the body, rather than a separate organ, and is the access point for bacteria to enter the bloodstream via the gums."
He and his colleagues analyzed data from 13,734 people living in the US who took part in the Third National Health and Nutrition Examination Survey (NHANES III).
They found 861 (6%) of the participants in the sample had chronic kidney disease, and they were typically followed for 14.3 years.
Comparable to the effect of diabetes
The researchers then assessed links between periodontitis and mortality in people with chronic kidney disease and compared them with the link between mortality and other risk factors in people with chronic kidney disease, such as diabetes.
After adjusting for the effect of other potential influencing factors, the team found that over 10 years, the rate of death due to any cause among survey participants with chronic kidney disease without periodontitis was 32%, while with periodontitis it was 41%.
- In the US, 47.2% of adults aged 30 years and older have some form of gum disease
- Prevalence increases with age: 70% of those aged 65 and over have it
- The condition is more common in men than women.
This is comparable to the effect of diabetes. The 10-year mortality in participants with chronic kidney disease without periodontitis rose from 32% in non-diabetics to 43% in diabetics, note the authors.
Periodontitis is a serious, chronic, non-communicable gum infection that damages the soft tissue and bone that supports the teeth. It is the sixth most common human disease and affects around 11.2% of the world's population.
The researchers note that kidney disease and other non-communicable disease are becoming more common - partly because the world's population is getting older, lifestyles are becoming less physically active and diets more refined.
The increase in these diseases is adding to global disease burden and health care costs: evidence suggests 92% of older adults now have at least one chronic disease.
Prof. Chapple explains that many people who have gum disease do not realize they have it. Perhaps they notice a bit of blood in their spit when they brush their teeth. However, if they don't have this checked out, they could inadvertently be raising disease risk for the rest of the body.
The team is now looking more closely at the link between gum disease and kidney disease, to see if the link is a coincidence or if gum disease causes kidney disease.
If they establish a causal connection, then they want to address the question of whether treating gum disease and increasing oral health improves prospects for kidney disease patients.
Prof. Chapple concludes:
"It may be that the diagnosis of gum disease can provide an opportunity for early detection of other problems, whereby dental professionals could adopt a targeted, risk-based approach to screening for other chronic diseases."
Meanwhile, Medical News Today recently reported progress on the development of a saliva test for identifying cancer that is soon to be tested in human patients.