Amazing Pre-Diabetes Studies

Gum Disease and Diabetes:  This article is from JAMA December 2008
Studies Probe Oral Health–Diabetes Link
Tracy Hampton, PhD

PHYSICIANS AND DENTISTS HAVE long known that the health of an individual’s mouth can have significant effects on the health of the rest of the body. The link between periodontal disease and heart disease is one of the most commonly known associations, but researchers are finding many more medical reasons to maintain good oral hygiene.

Diabetes, the focus of much attention lately due to its rising incidence, appears to have a particularly close relationship with conditions within the oral cavity. This relationship seems to go both ways—diabetes can lead to unwanted changes in the gums and periodontal tissues, and periodontal diseases—including gingivitis and severe periodontitis— can make it more difficult to control diabetes.


A number of recent studies have highlighted the give-and-take relationship between diabetes and oral health (Taylor GW and Borgnakke WS. Oral Dis. 2008;14[3]:191-203). Periodontal disease worsens diabetes when bacteria released into the bloodstream contribute to inflammation.

“There are significant data now to support that if a person has diabetes and they also have periodontal disease that is left untreated, it is very difficult to gain glycemic control of that patient,” said Maria Ryan, DDS, PhD, professor of oral biology and pathology, and director of clinical research at the School of Dental Medicine at Stony Brook University in New York.

For example, an analysis of data from the first National Health and Nutrition Examination Survey (NHANES I) revealed that individuals with periodontal disease were twice as likely to develop diabetes as persons without periodontal disease (Demmer RT et al. Diabetes Care. 2008;31[7]:1373- 1379). Another prospective study, of Pima Indians, a population with a very high rate of type 2 diabetes, found that periodontal disease was a strong predictor of mortality from diabetic nephropathy (Saremi R et al. Diabetes Care. 2005;28[1]:27-32).

When tartar collects above the gumline, it becomes more difficult to thoroughly brush and clean between teeth. This can create conditions that lead to chronic inflammation and infection in the mouth. Researchers suspect that periodontitis may adversely affect glycemic control because the proinflammatory cytokines produced by the infection could enter the bloodstream from the gingival tissues and lead to the development of insulin resistance.

“Periodontal infection affects the health of the teeth and gums, but the body’s response to that infection, we believe, is systemic,” said George Taylor, DrPH, DMD, associate professor of dentistry at the Schools of Dentistry and Public Health at the University of Michigan in Ann Arbor.

These effects may be evident even before clinical diabetes is recognized. As Ryan noted, periodontal disease is associated with higher levels of insulin resistance, often a precursor of type 2 diabetes, as well as with higher levels of glycated hemoglobin (HbA1c), which indicates suboptimal glycemic control of diabetes.

Diabetes can contribute to periodontal disease as well. “We also think that the body’s response to infection is exaggerated in people with diabetes—it makes them more susceptible to periodontal disease and makes it more severe,” said Taylor.

Studies looking at the effects of diabetes on periodontal disease have found that diabetes can weaken the connective tissue surrounding the gums and cause various adverse effects in the mouth. An analysis of NHANES III data indicates that women who develop gestational diabetes mellitus during pregnancy are at greater risk for developing periodontal disease than pregnant women who do not develop the condition (Novak KF et al. J Public Health Dent. 2006;66[3]:163-168).

Other oral problems associated with diabetes include salivary gland dysfunction, ulcers, infections, and dental caries. For example, lichen planus, a skin disorder that produces lesions in the mouth, is a condition associated with diabetes. Severe types of lichen planus involve painful ulcers that erode surface tissue. Diminished salivary flow and an increase in salivary glucose levels create an attractive environment for fungal infections such as thrush and oral candidiasis, which occurs more frequently among people with diabetes.

“There are a lot of oral complications of poorly controlled diabetes,” said Ryan. “If your blood glucose levels are high, it also gets into your saliva, which can increase cavities and increase risk of oral candidiasis or yeast infections,” she explained.

Therefore, proper care of the mouth may help patients with diabetes achieve better glycemic control, and appropriate management of diabetes may help prevent periodontal disease and other oral problems. However, while periodontal disease causes significant infection and inflammation of the tissues surrounding and supporting the teeth, individuals often do not know they have the condition because it is usually painless. Therefore, Taylor and others are advocating for a greater awareness of periodontal disease, particularly among physicians whose patients may not regularly visit the dentist.


Because diabetes can adversely affect oral health and poor oral health can worsen diabetic complications, dentists and physicians are beginning to realize the need to work together to ensure the health of their patients.

“For the first time ever, the American Diabetes Association has recommended to the physician that they ask when their patients last saw a dentist, and if they have not been seen by a dentist in the past year that they should recommend an oral evaluation,” said Ryan. “It’s also important that the dentist inform the physician of any oral infection or inflammation that’s being managed,” she added.

While it is unclear how many physicians and dentists communicate with each other, “as you start to see more information coming out on these connections, more of the medical community is becoming involved in oral care,” said Ryan. For example, Ryan and other dental researchers were invited to speak in June at the American Diabetes Association’s Annual Scientific Sessions in San Francisco, Calif. In addition, Taylor noted that the dentists’ and physicians’ perspectives are also both being represented in continuing education courses.

Health insurers are also realizing the value of linking dental and oral health. For example, Blue Cross Blue Shield of Michigan has created two referral forms, one from dentist to physician and the other from physician to dentist. The insurer also is incorporating preventive dental services into some medical plans.

However, many patients must deal with separate insurers when it comes to their dental and medical care. “Dentists are not reimbursed to screen for diabetes, so from the business side, they’d be spending time for services that cost them but that they’re not reimbursed for,” said Taylor. “The same happens with physicians,” he added.

Taylor noted that this situation highlights the need for more research on the benefits—including cost benefits—of linking medical and dental health. To that end, Taylor and others at the University of Michigan School of Dentistry are collaborating with Blue Cross Blue Shield of Michigan on a research project quantifying the medical savings of good oral care in patients with diabetes.

“We’re looking at costs from submitted medical claims for diabetes patients— physician costs, facility costs, prescription costs—and analyzing what kind of dental services the patient received,” said Carl Stoel, DDS, a senior dental consultant at Blue Cross BlueShield of Michigan. The goal is to compare the medical costs of patients who receive little or no dental services with costs of those who receive routine dental care.

“So far, we’ve found that when diabetic patients are good dental patients, there’s a substantial savings onthe medical side,” Stoel noted.

Specifically, the study has found a cost savings in the range of 3% to 8% for individuals who were receiving regular dental care each year compared with those who were not recipients of any preventive or periodontal services. The cost savings that were seen related to the following diabetes related complications: peripheral vascular disease, coronary heart disease, congestive heart failure, cardiovascular disease, and chronic kidney disease. “I hope that our research will provide the evidence to show that it can make a difference if physicians identify patients at risk for periodontal disease,” said Taylor.

Because many adults have gingivitis or periodontitis, and the incidence of diabetes is increasing, researchers predict that the links between dental disease and diabetes will become even more evident in the years to come. Ongoing studies are anticipated to contribute additional information highlighting the importance of simultaneously treating periodontal disease and optimizing glycemic control to prevent diabetic complications and maintain oral health. #

Oral Health Problems Linked to Diabetes

Patients with inadequate blood glucose control appear to develop periodontal disease more often and more severely, and they lose more teeth than individuals who have good control of their diabetes.

According to the American Dental Association, the most common oral health problems associated with diabetes are the following:

• tooth decay
• periodontal disease
• salivary gland dysfunction
• fungal infections
• lichen planus and lichenoid reactions (inflammatory skin disease)
• infection and delayed healing
• taste impairment

Physicians can play a role in encouraging patients’ oral health by recommending good maintenance of blood glucose levels, a well-balanced diet, good oral care at home, and regular dental checkups. When glycemia has been difficult to control, a physician might consider asking patients when they last saw their dentist and whether periodontitis has been diagnosed.

MEDICAL NEWS & PERSPECTIVES, 2472 JAMA, December 3, 2008—Vol 300, No. 21 (Reprinted) ©2008 American Medical Association. All rights reserved.