The team said this highlights the importance of good oral hygiene. Further research is needed to confirm if maintaining healthy gums can lower your stroke risk, particularly for those under fifty.
The Leskelä et al. study titled ‘Periodontitis, Dental Procedures, and Young-Onset Cryptogenic Stroke’ investigated individuals aged 18 to 49 who had encountered their initial cryptogenic ischemic stroke.
CIS refers to a subtype where the cause is not immediately identifiable despite comprehensive medical assessment.
Ischemic strokes, which account for about 87 per cent of all strokes, occur when an artery supplying blood to the brain is blocked, usually by a blood clot. In many cases, the underlying cause can be identified, such as atherosclerosis, cardiac arrhythmias (like atrial fibrillation), or small vessel disease.
Though less common overall, cryptogenic ischemic strokes are more characteristic in younger adults, where traditional risk factors like hypertension, diabetes, and atherosclerosis are more prevalent.
Participants underwent detailed clinical and radiographic oral examinations and oral bacterial presence in their blood by serum levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA).
Published in the Journal of Dental Research (JDR), the study carefully adjusted for various stroke risk factors, regular dental visits, and the presence of a patent foramen ovale (PFO), a small hole in the heart that can allow returning venous blood clots-or bacteria- to pass directly in the arterial bloodstream.
Gum diseases doubles the risk of strokes
Leskelä et al. noted that individuals with severe gum disease had up to twice the risk of experiencing a stroke. Notably, these individuals did not have traditional stroke risk factors, such as high blood pressure or cholesterol.
The study also showed that patients who had advanced periodontitis (classified as stage III to IV, grade C) were 6.43 times more likely to experience a severe stroke compared to those without such severe periodontitis. This indicates that periodontitis might not only potentially increase the risk of stroke but could also contribute to the stroke's severity when it occurs.
The impact of recent dental treatments was also examined in the trial. According to the study, invasive dental treatments performed within three months prior to the stroke were associated with a higher risk of CIS, with an odds ratio (OR) of 2.54. This risk was even more pronounced in individuals with patent foramen ovale (PFO), who had an OR of 6.26. This finding emphasises the potential impact of recent invasive dental procedures on stroke risk, particularly in those with certain pre-existing health conditions.
Bleeding gums are a red flag
Pirkko Pussinen, a professor from the University of Eastern Finland, who participated in the study, emphasised that gingivitis and periodontitis affect most adults. She expressed concern that oral infections are often not taken seriously enough despite the significant health risks they pose.
Pirkko highlighted a key warning sign: if your gums bleed when you brush your teeth, gingivitis (gum inflammation) is already present, and immediate action is required.
The link between oral and brain health is a growing topic of interest.
In March 2024, Olli Patrakka examined in his dissertation in forensic medicine the role of oral bacteria, particularly viridans group streptococci, in the development of strokes.
Viridans group streptococci are normal microbes in the mouth, but once they enter the bloodstream, they can cause serious diseases such as endocarditis (infection of the heart valves). They can enter the bloodstream through inflamed gums, for example, while brushing teeth.
These bacteria adhere to the surface of the teeth and initiate the process leading to the formation of dental plaque. Our hypothesis is that a similar phenomenon occurs when bacteria that enter the bloodstream during dental procedures or gum infections migrate into the arterial walls. This may accelerate the development of atherosclerosis, or hardening of the arteries, and inflammation, contributing to both strokes and coronary artery disease, Patrakka described.
Poor oral hygiene: A risk factor for stroke needing more attention
According to Olli, dental bacteria can be found in the cerebral blood clots of stroke patients in approximately four out of five cases. This finding had not been previously reported.
For the study, cerebral blood clots from stroke patients treated in Tampere, Finland, were collected during acute care. Additionally, samples included endarterectomy tissue from patients with symptomatic carotid artery stenosis.
Epidemiological studies have shown that poor oral hygiene is an independent risk factor for stroke and improving hygiene habits may decrease the risk.
Olli said, “My research suggests that the connection might be specifically explained by an inflammatory reaction caused by dental bacteria in atherosclerotic plaques.”
The findings of the dissertation are significant as they open new possibilities for treating patients who have suffered a stroke.
“The development of a vaccine might also be possible”, Olli speculated.
What are the practical implications?
“The study reinforces the view that oral health must be maintained, especially for those at risk of stroke”, said Tommi Pätilä, a heart and transplant surgeon at the New Children's Hospital in Helsinki, Finland.
According to Tommi, inflammation caused by oral streptococcal bacteria should always be considered in stroke prevention as part of regular dental care. It is also crucial to explore the potential benefits of timely antimicrobial treatment or a bacterial vaccine in the future.
Periodontitis behind many ailments
Studies show that dental plaque bacteria are responsible for about 95 per cent of oral diseases. One of the most common oral diseases is gum disease caused by dental plaque, known as gingivitis. Early signs of this widespread disease include red and bleeding gums, and bad breath.
If the inflammation is not treated promptly and oral hygiene is not improved, gingivitis may progress to more severe gum disease, periodontitis. Then, fibers that attach to the tooth are destroyed, leading to the formation of a pocket between the gum and the tooth. This pocket can expand around the entire tooth, destroy more of the tooth's supporting tissues and eventually the jawbone.
Careful mechanical brushing of the teeth and cleaning between the teeth is important because even asymptomatic oral infections can affect overall health.
According to a Health 2011 follow-up survey, three out of four people in Finland over the age of 30 suffer from gingivitis, whereas half showed very mild signs of early periodontitis.
Tommi noted that this globally common oral disease can lead to tooth loss if left untreated, but it is also linked to systemic noncommunicable diseases (NCDs). Among the significant NCDs are diabetes mellitus, cardiovascular diseases, depression, neurodegenerative conditions, rheumatic illnesses, inflammatory bowel disease, gastric helicobacter pylori, stroke, obesity, diabetes mellitus or asthma.
Tommi said, “Statistics show that people with healthy mouths live longer. Each missing tooth reduces life expectancy. This is talked about far too little.”
According to Liljestrand et al. even a few missing teeth may indicate an increased risk of health issues such as cardiovascular diseases and diabetes – and even premature death. When individual risk factors for chronic diseases are assessed, the number of missing teeth could be a useful additional indicator for general medical practitioners, the researchers explained.
References are available on request.