UW News

September 19, 2000

No apparent connection between periodontal disease and coronary heart disease

A thorough study suggests there is little or no connection between periodontal disease and risk of coronary heart disease, according to researchers at the University of Washington School of Dentistry.

The idea that people can prevent heart disease by simply reducing periodontal disease sounds alluring. There is even a popular phrase, “floss or die,” that refers to this possibility. However, there is little evidence to date to support this recommendation. First, researchers say, there needs to be convincing evidence that periodontitis indeed causes chronic coronary heart disease. Second, there needs to be evidence that treating periodontitis will result in a decreased incidence of chronic coronary heart disease. Neither has been shown, researchers said.

“There is no evidence that any dental treatment will have a positive impact on chronic coronary heart disease. It may even be that there is no association at all between periodontitis and chronic coronary heart disease. Our analysis suggests that the association is either non-existent or of such small size that it will be very difficult to come up with convincing evidence,” said one of the authors, Dr. Philippe Hujoel, an associate professor in the Department of Dental Public Health Sciences in the School of Dentistry and of epidemiology in the School of Public Health and Community Medicine.

The findings are reported in the Sept. 20 issue of the Journal of the American Medical Association.

Other authors include Dr. Timothy A. DeRouen, professor and chairman of dental public health sciences in the School of Dentistry and professor of biostatistics in the UW School of Public Health and Community Medicine; Dr. Mark Drangsholt, instructor of dental public health sciences and the Department of Oral Medicine; and Dr. Charles Spiekerman, research scientist in the departments of Dental Public Health Sciences and Biostatistics.

The challenge to doing this kind of analysis is determining cause and effect. Someone may have both periodontal disease and heart disease; but how do you know if one caused the other? Both conditions share the same risk factors. For example, people who smoke are at high risk of developing both problems. Other shared risk factors include stress, socioeconomic status, obesity and increasing age.

“Trying to figure out if periodontal disease actually causes heart disease, with the presence of all these shared risk factors, is very difficult,” DeRouen said.

So to make their way through this complex statistical analysis, UW researchers used a federal database that examined several thousand people — before any had apparent heart disease — and then followed their health for 20 years. Fortunately, the status of their gums and teeth was diagnosed at the onset of the study with painstaking detail, and researchers also charted a very comprehensive collection of other variables such as smoking, serum cholesterol levels, and physical activity. Because of the number of people and the number of years involved in the UW analysis, this is believed to be the broadest and most thorough study of this question.

“These data were collected in the early ’70s. Our analysis did not include those people who had a history of heart disease at that time — it looked at who developed chronic coronary heart disease among more than 8,000 other people, some of whom had periodontal disease and some of whom did not,” Drangsholt said. What the researchers found after screening for all the variables and using statistical models that weeded out the risk factors was that there remained only a slight connection between periodontal health and subsequent heart disease and death.

“We’ve pretty much eliminated, with this study, the possibility of a connection that is modest to large. We can’t eliminate the possibility that there is a very small effect,” DeRouen said.

The study does not address other reported connections between systemic health and periodontal disease, such as links other researchers have reported between gum disease and low-birth-weight babies. The paper says there may be ways that the health of your mouth may affect the rest of your body — but chronic coronary heart disease does not seem to be one of those ways.

The researchers say there are still plenty of good reasons to floss, if only to prevent gingivitis, an inflammation of the gums.