Gum Disease Linked to COVID-19 Complications

COVID-19 patients are at least three times more likely to experience complications if they also have gum disease, according to an international team of researchers.

The study of more than 500 patients with COVID-19 found that those with gum disease were 3.5 times more likely to be admitted to intensive care, 4.5 times more likely to need a ventilator, and almost nine times more likely to die compared to those without gum disease.

Also, blood markers indicating inflammation in the body were significantly higher in COVID-19 patients who had gum disease compared to those who did not, suggesting that inflammation may explain the raised complication rates.

“The results of the study suggest that the inflammation in the oral cavity may open the door to the coronavirus becoming more violent,” said Lior Shapira, president-elect of the European Federation of Periodontology (EFP). “Oral care should be part of the health recommendations to reduce the risk for severe COVID-19 outcomes.”


Periodontitis affects up to half of all adults worldwide. It causes inflammation of the gums, and, if left untreated, inflammation can spread throughout the body. COVID-19 is associated with an inflammatory response that may be fatal.

The nationwide case-control study was conducted in Qatar, which has electronic health records including medical and dental data. It included 568 patients diagnosed with COVID-19 between February and July 2020. Of these patients, 40 had complications such as intensive care unit (ICU) admission, ventilator requirements, or death, and 528 did not.

Information was collected on gum disease and other factors that might be associated with COVID-19 complications including body mass index (BMI), smoking, asthma, heart disease, diabetes, and high blood pressure. Data also was obtained on blood levels of chemicals related to inflammation in the body.

Of the 568 patients, 258 (45%) had gum disease. After adjusting for age, sex, BMI, smoking status, and other conditions, the odds ratios for COVID-19 complications in patients with gum disease, compared to those without gum disease, were 3.67 for all COVID-19 complications, 3.54 for ICU admission, 4.57 for ventilator requirement, and 8.81 for death.

If a causal link is established between periodontitis and increased rates of adverse outcomes in COVID-19 patients, the researchers said, establishing and maintaining periodontal health may become an important part in their care.

Also, oral bacteria in patients with periodontitis can be inhaled and infect the lungs, particularly in those using a ventilator, said researcher Mariano Sanz of the Complutense University of Madrid.


“This may contribute to the deterioration of patients with COVID-19 and raise the risk of death,” Sanz said. “Hospital staff should identify COVID-19 patients with periodontitis and use oral antiseptics to reduce transmission of bacteria.”

The association between periodontitis and lung diseases including asthma, pneumonia, and chronic obstructive pulmonary disease is well established, Shapira said.

“This study adds further evidence to the links between oral health and respiratory conditions. Periodontitis is a common disease but can be prevented and treated,” Shapira said.

“This study highlights another association between gum disease and our systemic health and reiterates the need for ongoing, lifelong dental care for people susceptible to gum disease and a strong preventive approach to periodontitis for populations as a whole,” said Nicola West, EFP secretary general.

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