Scientists believe they have found a way to identify the earliest warning signs of cardiovascular disease from a simple saliva sample.
Periodontitis is a common infection of the gums which has previously been linked to the development of cardiovascular disease: scientists suspect that inflammatory factors may enter the bloodstream through the gums and damage the vascular system.
The team from Mount Royal University in Canada used a simple oral rinse to see if levels of white blood cells -- an indicator of gum inflammation -- in the saliva of healthy adults could be linked to warning signs for cardiovascular disease.
They found that high levels correlated with compromised flow-mediated dilation, an early indicator of poor arterial health.
"Even in young healthy adults, low levels of oral inflammatory load may have an impact on cardiovascular health -- one of the leading causes of death in North America," said Trevor King of Mount Royal University.
In the study, published in Frontiers in Oral Health, the team examined currently healthy young people without diagnosed periodontal issues to determine whether lower levels of oral inflammation can be clinically relevant to cardiovascular health.
"We are starting to see more relationships between oral health and risk of cardiovascular disease," said Ker-Yung Hong, first author of the study, now studying dentistry at the University of Western Ontario.
"If we are seeing that oral health may have an impact on the risk of developing cardiovascular disease even in young healthy individuals, this holistic approach can be implemented earlier on."
The team chose pulse-wave velocity, which can measure the stiffness of arteries, and flow-mediated dilation, a measure of how well arteries can dilate to allow for higher blood flow, as key indicators of cardiovascular risk. These measure arterial health directly: stiff and poorly functioning arteries raise patients' risk of cardiovascular disease.
The scientists recruited 28 non-smokers between 18 and 30, with no comorbidities or medications that could affect cardiovascular risk and no reported history of periodontal disease.
They were asked to fast for six hours, except for drinking water, prior to visiting the lab.
At the lab, participants rinsed their mouths with water before rinsing their mouths with saline which was collected for analysis.
Participants then lay down for 10 minutes for an electrocardiogram and stayed lying down for another 10 minutes so that the scientists could take their blood pressure, flow-mediated dilation, and pulse-wave velocity.
The scientists found that high white blood cells in saliva had a significant relationship to poor flow-mediated dilation, suggesting these people may be at elevated risk of cardiovascular disease.
However, there was no relationship between white blood cells and pulse wave velocity, so longer-term impacts on the health of the arteries had not yet taken place.
In the pilot study, the scientists hypothesised that inflammation from the mouth, leaking into the vascular system, impacts the ability of arteries to produce the nitric oxide that allows them to respond to changes in blood flow.
Higher levels of white blood cells could have a greater impact on vascular dysfunction; the levels found in the participants are usually not considered clinically significant.
