Spring 2018

Is Periodontal Disease in Our Genes?

Data from long-term health studies may hold the answer.

By David Levin

Previous Next

Illustration: Stuart Bradford

In patients who develop periodontal disease, it’s not unusual to develop coronary heart disease as well. If there is a genetic link between the two disorders, however, the exact relationship between them hasn’t yet been found. For the past several years, Yau-Hua Yu, assistant professor of periodontology, has been looking for a connection.

Yu has been awarded a career development award from the National Institutes of Health to focus on this topic. Some studies of twins, Yu said, have found evidence of a genetic component to periodontal disease—if one sibling developed it, so did the other. Those findings suggest that something in their DNA was responsible. And yet that apparent link in twins doesn’t extend to the level of the greater population—in other words, Yu said, a person may have a gene associated with the development of periodontal disease, but the specific gene that causes it may vary from patient to patient. When researchers look at the genome of a large group of people, there’s no clear evidence of a common pattern for periodontal disease shared in their DNA. “There are hundreds of genomic markers for cholesterol level, blood pressure, schizophrenia, autism, and others that have a strong significance, but we don’t see the strong signals for periodontal disease,” Yu said. “It’s perplexing.”

Part of the challenge Yu faces in her research is that not many studies of periodontal disease involve cohorts large enough to examine the disease on a population level. Most previous studies have recruited only a few hundred or a few thousand patients to study—a genomic analysis would require tens of thousands.

To get around that limitation, Yu decided to look for relevant data in unrelated studies of larger groups of patients. As it turned out, the Women’s Health Study, a landmark project based out of Harvard Medical School, provided a tantalizing opportunity. The Harvard study followed nearly 40,000 middle-aged women from 1993 to 2004, in an effort to test whether vitamin E and aspirin can help prevent cardiovascular disease. Along the way, researchers recorded each patient’s comprehensive medical history. That wealth of data let Yu identify any patients who showed both cardiovascular disease and periodontal disease.

Women who developed periodontal disease after starting the study, Yu found, had just as high a likelihood of developing cardiovascular disease later in life as those who had existing periodontal disease—a finding that hinted at a genetic pathway that might be shared by patients with both conditions. Although the finding still hasn’t revealed what that pattern actually is, it tells her she’s on the right track.

To dig deeper in the future, Yu said, she’ll need to bulk up her dataset, pulling in information from dozens of additional studies. She’ll also need to look at patient biology on multiple different levels—each patient’s complete genome, their individual genes, and the proteins that those genes create using other resources. It will be no small feat, but Yu is prepared to tackle it.

“That’s how it is with periodontal disease—we’re using all the available data we can find, and starting to come up with a story,” she said. “We just have to know how to connect the dots.”

Top Stories

Editor's Picks