BY Richard H. Nagelberg, DDS
What exactly is insulin resistance (IR), and why should we as dentists care? We have too much on our plates already with the dental needs of our patients and administering our practices. As it turns out, IR may be one of the most important considerations for the overall health of our patients and us!
Insulin resistance is a disease process unto itself that eventually leads to diabetes. Prediabetes and diabetes are nothing more than statistical diagnoses. If the fasting blood sugar or HbA1c levels reach a certain point, the diagnosis is made. This is the reason why millions of people became diabetic overnight back in 1997. That was when the American Diabetes Association changed the parameters defining a diagnosis of diabetes from a fasting blood sugar of >140 to >125. All those individuals sitting pretty back in 1997 at 130 instantly became diabetic because of the statistical change.
Insulin’s function is to clear glucose from the bloodstream and allow it to be used by our tissues to power their metabolic activities. When IR occurs, glucose transport out of the bloodstream and into the tissues is impaired, causing the sugar to back up in the bloodstream. The beta cells in the pancreas respond to the hyperglycemic conditions by pumping out still more insulin. These events happen again and again, each time food is consumed. Over a period of years, the overworked beta cells burn out, insulin production cannot keep up with the demand, and type 2 diabetes is diagnosed.
This is damaging enough by itself, but the problem compounds in serious ways, most notably because high levels of insulin are damaging to arteries. Several mechanisms are involved in arterial damage from high levels of insulin, including lowering HDL, raising triglycerides, increasing LDL, increasing blood pressure, and causing endothelial dysfunction, among others.
It is worth noting that this is not a function of the elevated levels of glucose. It is the high levels of insulin driving arterial disease, not high glucose levels. Hyperglycemia presents its own constellation of problems.
The primary problem associated with elevated levels of insulin, however, is its effect on atherosclerosis. Insulin resistance is the biggest root cause of atherosclerosis by the mechanisms noted. Moreover, this can occur independently from blood sugar levels and diabetes. Atherosclerosis is the initiating event for cardiovascular diseases, including heart attack, stroke, kidney disease, or other organ systems depending on the arteries involved.
To summarize: Insulin resistance elevates glucose levels … elevated glucose levels result in increased insulin output … and elevated levels of insulin cause arterial damage. This series of events is the reason why IR is a major cause of atherosclerosis. Since periodontal disease increases insulin resistance, there appears to be an oral-systemic connection between periodontal disease and atherosclerosis.
As dental professionals, we need to be concerned about this because research has shown an association between atherosclerosis and periodontal disease and the perio pathogens. A 2011 study in the American Journal of Cardiology by Fifer et al. found direct evidence for an association between periodontal disease and atherosclerotic inflammation of arteries. A 2009 study by Pesonen et al. concluded that bacteria, including two perio pathogens, are associated with atherosclerosis and coronary obstruction. It is important to recognize these are two different mechanisms. One relates to periodontal disease and the other to the effect of the periodontal pathogens Aa and Pg, independent of clinical disease. Patients with a strong family history of cardiovascular disease may be well advised to undergo salivary diagnostic testing to potentially identify periodontal pathogens, even if they do not have periodontal disease. This may seem radical at this time, but may become routine in the future as more evidence is revealed.
The weight of the evidence is so compelling at this point that some physicians are starting to act on the information. A particularly interesting example is a recent case of vascular dementia in an elderly patient, with two highly virulent periodontal pathogens being identified as the etiological agents.
The imperative to provide periodontal treatment for every patient is critically important for the patient’s health beyond the oral cavity. Going forward, cooperative patient management will occur more frequently among dental and medical professionals. We are in a unique position to diagnose, screen, and refer patients for medical consultations for a number of conditions. Thinking beyond the patients’ mouths should be routine at this point in time.
DR. RICHARD NAGELBERG has practiced general dentistry in suburban Philadelphia for more than 29 years. He is a speaker, advisory board member, consultant, key opinion leader for several dental companies and organizations, and lecturer on a variety of topics centered on understanding the impact dental professionals have beyond the oral cavity. Contact him at [email protected].
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