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New research finds a link between COVID-19 severity and gum disease. Nes/Getty Images
  • Researchers at McGill University find a strong link between periodontitis, a common form of gum disease, and severe COVID-19 outcomes.
  • Periodontitis produces an inflammatory response that may spread through the body — scientists have previously linked the condition to other systemic issues.
  • People with periodontitis were 8.8 times more likely to die of COVID-19.
  • Individuals can reduce the risk of periodontitis by practicing strong oral hygiene.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

One of the more perplexing things about COVID-19 is its wide range of outcomes in people who get the disease. A new study from researchers at McGill University in Montreal, Canada, finds a link between gums with inflammation and infection and COVID-19 complications and deaths.

The study finds that people with periodontitis are 8.8 times more likely to die of COVID-19.

In addition, such individuals are 3.5 times more likely to require hospitalization for COVID-19 and 4.5 times more likely to require a ventilator.

Contributing author Prof. Belinda Nicolau of McGill’s Faculty of Dentistry tells McGill Newsroom:

“Looking at the conclusions of our study, we can highlight the importance of good oral health in the prevention and management of COVID-19 complications. There is a very strong correlation between periodontitis and disease outcome.”

The study appears in the Journal of Clinical Periodontology.

Periodontitis is the clinical term for serious infection due to the accumulation of bacteria between the teeth and gums. Without treatment, it can cause painful abscesses and tooth movement, damage teeth, and eat away at the underlying jawbone.

People may be able to prevent periodontitis with good oral hygiene, including daily flossing, brushing, and maintaining a schedule of regular dental examinations.

According to co-author McGill Ph.D. student Wenji Cai, “Periodontitis has been considered as a risk factor for a number of both oral and systemic diseases.” Scientists have also found links between the condition and heart disease, diabetes, and respiratory disease.

There are also associations between gum disease and an increased risk of pregnancy complications such as preeclampsia and low fetal birth rate.

Cai says, “Periodontitis causes inflammation of the gums and, if left untreated, that inflammation can spread throughout the body.”

The researchers report that periodontitis is the most common dental disease in Canada, affecting 7 out of 10 people at some point in their lives. “It’s an invisible pandemic,” Cai comments.

“We need to raise awareness of the disease and make more effort to maintain periodontal health, especially during this global pandemic.”

The researchers analyzed electronic health and dental records for 568 patients in the State of Qatar from the Hamad Medical Corporation, which manages the public health and dental system for that country.

Cai explains, “In Qatar, the medical and dental records happened to be digitized, which made it possible to collect data and conduct this research swiftly.” The researchers’ cross-sectional analysis took “various factors into consideration, such as demographic, medical or behavior factors, to avoid biases,” he says.

The researchers’ analysis found that biomarkers signifying inflammation were present at significantly higher levels in the blood of COVID-19 patients who also had periodontitis.

“In patients with severe cases of COVID-19,” notes Cai, “the virus causes an inflammatory response that can lead to complications such as being intubated or even death. Our research shows that periodontitis can [exacerbate] this.”

Senior author Dr. Faleh Tamimi told Medical News Today in an email, “What we suspect is happening is that upon COVID-19 infection, periodontal patients start the course of the disease with an already high level of inflammation in their bodies.”

“This puts the patients at a disadvantage if their COVID-19 disease derives in hyperinflammation, rendering them more susceptible to the severe outcomes of the disease.”

The authors of the study caution that their research has a couple of limitations.

Firstly, the study does not establish a causal relationship between periodontitis and severe COVID-19 outcomes, only an association between the two.

“In addition,” Dr. Tamimi told MNT, “Due to the limited sample size of our study, we clustered the four different stages of periodontal disease into two categories. By merging stages 0–1 and 2–4, this allowed us to see the overall association between periodontitis and COVID.”

However, the authors note that the study’s blinded assessment of dental radiographs by independent reviewers and the solidly representative nature of their population sample may somewhat mitigate these concerns.

The study concludes:

“Future research, including interventional studies focused on the influence of periodontitis and periodontal treatments on COVID‐19 infections, would help better understand the causal connections between them.”

“Furthermore, understanding the mechanisms underpinning the relationship between periodontitis and COVID‐19 complications is a promising area of research that may produce mechanistic targets, risk stratification, and novel interventions.”

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