SAN FRANCISCO — Evidence continues to accumulate that periodontal disease is associated with insulin resistance and poor glycemic control, and there are tantalizing suggestions that treating periodontitis may lead to improvements in glycemic control.
That was the message delivered by the speakers at the first joint symposium of the two ADAs—the American Dental Association and the American Diabetes Association—at the annual scientific sessions of the American Diabetes Association.
The speakers agreed that systemic inflammation appears to form the critical link between periodontitis and diabetes, although the chicken-and-egg question has not yet been answered. Diabetes appears to induce periodontal disease or cause it to worsen in some patients, but periodontal disease seems to worsen glycemic control. Periodontal disease also seems to increase the risk of cardiovascular disease and stroke and, when present in pregnant women, to increase the risk of low-birth-weight babies.
Whatever the direction of causation, the clear message was that dentists must ask their patients about diabetes, and physicians must inquire about the oral health of their diabetes patients.
Some of the evidence comes from analyses of the third National Health and Nutrition Examination Survey (NHANES III—data compiled between 1988 and 1994) by George W. Taylor, D.M.D., of the University of Michigan, Ann Arbor. In one analysis that included individuals between the ages of 17 and 90, Dr. Taylor and his colleagues looked at the presence or absence of periodontitis and metabolic syndrome and their relationship to insulin resistance. Among patients with neither disorder, 10% demonstrated insulin resistance. The rate of insulin resistance increased significantly to 36% among patients who had only periodontitis, to 53% among patients who had only metabolic syndrome, and to 48% among patients who had both.
After adjustment for education, age, race/ethnicity, exercise, smoking history, white blood cell count, fibrinogen levels, and levels of C-reactive protein, those with periodontitis alone were 3.7 times as likely to have insulin resistance as were those with neither disorder. The risk increased 7.3-fold among patients with metabolic syndrome alone, and 6.8-fold among patients with both disorders.
The question remained, however, whether treating periodontitis would improve glycemic control. In a systematic review, Dr. Taylor found that 5 of 8 randomized controlled trials and 8 of 12 other studies returned positive answers to that question.
Periodontist Lewis F. Rose of the University of Pennsylvania, Philadelphia, was one of 18 physicians, dentists, and other independent experts who convened in Scottsdale, Ariz., in April 2007 to review the strength of the evidence for the associations among periodontitis, diabetes, and cardiovascular disease. The participants in the Scottsdale Project conducted a systematic review of 118 published articles in an attempt to answer eight focused questions.
Despite some uncertainty in the evidence, the panel agreed that it would be appropriate to develop guidelines to assist dental providers in identifying patients who are at risk for diabetes or cardiovascular disease and, conversely, to develop guidelines to assist medical providers in identifying patients who are at risk for periodontal disease.
Dr. Rose noted that one physician on the panel said, “I can't believe we're going to be asked to identify another problem in a 15-minute period in our patients.”
Dr. Rose acknowledged the difficulty of squeezing yet another item into limited appointment times. Even so, he said that it would not take much time simply to ask patients with diabetes whether they had seen a dentist within the last year.
Dr. Rose said that he had no conflicts of interest related to his presentation. Dr. Taylor acknowledged serving as a consultant to, and advisory board member for, Colgate-Palmolive, and the company sponsored the joint symposium with an unrestricted educational grant.