Early Clues to Heart Disease Risk

What’s Up?
If you smoke, have a family history of heart disease, or are packing on the fast-food pounds, a future trip to the dentist might just alert you that it’s time for a lifestyle change.

In a recent study, an oral enzyme was proven to be an earlier indicator of heart disease than the traditional blood protein cardiologists look at when prescribing preventive drugs such as statins.

Researchers at Boston University and the University of Helsinki found that an enzyme called salivary lysozyme (SLZ), a marker for oral infection and hyperglycemia, was also an indicator of metabolic syndrome—a cluster of risk factors for coronary artery disease, stroke, and type 2 diabetes—in people with heart disease. Traditionally, the level of C-reactive protein (CRP) found in the blood, which indicates inflammation and infection, is used as the biomarker for a person’s risk for heart disease. But SLZ was associated with an earlier stage of heart disease than even hypertension, another risk factor.

“In other words, SLZ is a marker for heart disease very early on,” says Sok-Ja Janket, a research associate professor at the Henry M. Goldman School of Dental Medicine and one of the study’s lead authors.

What was found
The Kuopio Oral Health and Heart Study, conducted in Helsinki, Finland, examined cross-sectional data from 250 patients with coronary heart disease (CAD) and 250 without CAD. The results showed that persons with higher lysozyme levels were more likely to have metabolic syndrome, hypertension, and CAD after adjustment for C-reactive protein and other pertinent competing risk factors such as age, gender, smoking, BMI, diabetes, and the ratio of total cholesterol to HDL cholesterol.

Janket and her colleagues observed that high levels of SLZ displayed a stronger association with metabolic syndrome in the group with coronary artery disease than high levels of C-reactive protein. Oral infection has close ties with systemic inflammation measured by CRP.

“Taken together, this study indirectly suggests that improving oral health may be a prudent approach before dispensing expensive medicines such as statins,” Janket says, “but we need to look at changes in metabolic syndrome markers with dental treatment in the future.”

Why it matters
An earlier predictor of heart disease risk means people would still have time to make lifestyle changes that could improve their coronary health, Janket says. She envisions a scenario where any general dentist could take a saliva sample to test the level of the oral enzyme and send it off to the lab for analysis.

“As a public health researcher, I feel giving medication to asymptomatic people should be reserved as a last resort,” she says. “Instead of popping pills, we could encourage quitting smoking, losing weight, and exercise. Right now, people might be eating really bad diets, continue to smoke, and not exercise, and think that a cholesterol pill will take care of all the ill-effects of an unhealthy lifestyle.”

Word to the wise
“What we have so far is a theoretical assumption,” Janket says. “We won’t know whether improving oral health will decrease the early markers of heart disease until we do a clinical trial.” If she’s able to get funding, a trial could take place in 2011 and finish in 2013.

Where to find out more
Janket’s research was published in the September 2010 issue of the Journal of Clinical Periodontology. Read an abstract of the study here.

Caleb Daniloff can be reached at cdanilof@bu.edu.