The ongoing Swedish study previously found that gum disease ("periodontitis") was much more common in first-time heart attack patients than in a group of healthy people.

In this follow-up study, the researchers examined whether gum disease was associated with an increased risk of new heart problems in both heart attack survivors and healthy people the same age and sex, and living in the same area.

"The risk of experiencing a cardiovascular event during follow-up was higher in participants with periodontitis, increasing in parallel with the severity. This was particularly apparent in patients who had already experienced a [heart attack]," said study author Giulia Ferrannini, from the Karolinska Institute in Stockholm.

The researchers suspect that damage to the gum tissue in people with gum disease may allow germs to enter the bloodstream. "This could accelerate harmful changes to the blood vessels and/or enhance systemic inflammation that is harmful to the vessels," Ferrannini added.

In total, the study included nearly 1,600 participants with an average age of 62. Dental examinations between 2010 and 2014 showed that 985 had good dental health, 489 had moderate periodontitis and 113 had severe periodontitis.

During an average follow-up of just over six years, people with gum disease were 49% more likely to die from any cause, have a nonfatal heart attack or stroke, or to develop severe heart failure.

The risk of those outcomes increased with the severity of gum disease, according to the study presented Friday at a virtual meeting of the European Society of Cardiology. Such research is considered preliminary until published in a peer-reviewed journal.

When assessed separately, the relationship between gum disease severity and the risk of negative outcomes was significant only for those who had experienced a heart attack in the past.

"Our study suggests that dental screening programs including regular check-ups and education on proper dental hygiene may help to prevent first and subsequent heart events," Ferrannini concluded in a meeting news release.