For the Media Genetic Marker Common in People of European Heritage Doesn't Explain High Rates of Periodontal Disease in Chinese

CHICAGO – February 28, 2000 – A genetic marker strongly associated with periodontal disease does not play a role in the high prevalence of periodontal disease in people of Chinese heritage, according to a study released today in the February issue of the Journal of Periodontology.

The Interleukin-1 (IL-1) genotype that puts more than 30 percent of people of European heritage at increased risk for periodontal disease is barely existent in Chinese populations. The study tested 300 people of Chinese heritage, and only about 2 percent carried the IL-1genotype. "Periodontal disease is a multifactorial disease," said the study's lead author, Gary Armitage, D.D.S., M.S., professor and chairman of the Division of Periodontology at the University of California San Francisco. "We don't know yet whether oral hygiene, genetics or any other risk factor is most important in explaining why periodontal disease is widespread in Chinese populations."

A separate study in this month's Journal of Periodontology confirmed that people of Northern European origin who have the IL-1 genotype are more than five times as likely to develop periodontal disease, making oral hygiene habits, smoking and genetics among the top risk factors for periodontal disease.

The study concluded that giving dental patients a genetic test, which can be performed through a saliva sample, before they even show signs of periodontal disease and getting them into early interventive treatment might help them keep their teeth for a lifetime. "IL-I genotyping, combined with finding out a patient's smoking history, could go a long way in helping dental professionals estimate the future course of the disease. This helps us provide treatment and modify patients' behavior to improve their odds," said Michael McDevitt, the study's lead researcher and a periodontist practicing in Atlanta.

However, McDevitt said at this time it is cost-prohibitive to perform the test on every patient. He said he has found the test useful for specific cases, such as for patients with advanced periodontal disease who seem to lack other major risk factors, for adults considering orthodontic treatment that could make them more susceptible to bone loss around the teeth, and for patients considering extensive treatment to save teeth jeopardized by periodontal disease.

Armitage's study questions the usefulness of genetic testing for Chinese patients until further research is done. "In future studies, it will be interesting to determine if other gene candidates contribute to periodontal disease in Asians," said Armitage. He noted that past research has found different genes in Asians than in Caucasians play roles in susceptibility to other diseases, such as heart disease and diabetes.

The presence of IL-1 affects the inflammatory response in the gum tissue when bacteria are present, making the gum tissue more susceptible to reacting negatively. "The IL-1 genotype can play a role in making periodontal disease more severe," explained Jack Caton, D.D.S., M.S., president of the American Academy of Periodontology (AAP). "However, if the harmful bacteria are kept under control with good oral hygiene and frequent dental visits, a person with the IL-1 genotype is certainly not sentenced to having periodontal disease."