Definition
Diabetes mellitus is a group of metabolic diseases characterized by high blood glucose levels (hyperglycemia) and the inability to produce and/or use insulin. The disease is defined by abnormal blood glucose levels and utilization and is classified by the American Diabetes Association (ADA) into four general types ( Box 14.1 ). Each type is distinguished by the underlying mechanism, and each type demonstrates different levels of glycemia.
| Type 1 |
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| Type 2 |
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| Other specific types |
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| Gestational |
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Diabetes is a chronic condition that may affect persons of all ages. Persistent hyperglycemia leads to metabolic and vascular complications. The vascular complications include premature macrovascular disease and serious microvascular disease. The metabolic component involves the elevation of blood glucose associated with alterations in lipid protein metabolism, resulting from a relative or absolute lack of insulin. Maintenance of tight glycemic control can prevent or retard the development of microvascular complications of diabetes, including oral complications. The vascular component includes an accelerated onset of nonspecific atherosclerosis and a specific microangiopathy that particularly affects the eyes and kidneys. Retinopathy and nephropathy are eventual complications in nearly every person with chronic diabetes. These complications result in serious and costly morbidity.
Diabetes mellitus is of importance because:
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Dentists and hygienists will have many patients who have diabetes.
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Dentists and hygienists are in a position as members of a health care team to detect many persons who are not yet diagnosed or poorly controlled.
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Diabetes affects oral health, and oral health affects diabetes (it is bidirectional).
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Dentists and hygienists must be able to render care to patients already under medical management for their disease without endangering their well-being.
A crucial aspect of care of dental patients who have diabetes is determination of the level of disease severity and the level of glycemic control, as well as the presence of complications from diabetes, so that appropriate dental treatment can be provided. Essential to this determination is knowledge of the patient’s blood glucose level at the time that dental treatment is provided.
COMPLICATIONS: Patients with diabetes undergoing dental treatment may not be diagnosed and may be at risk for complications such as unconsciousness, infection, bleeding, drug interactions, and side effects. These events could prove serious. The dentist must be able to identify these patients, assess risk based on history and clinical findings, and work closely with the managing physician to develop a dental management plan that will be effective and safe for the patient.
Epidemiology
More than 250 million persons worldwide have diabetes mellitus, and health officials estimate that this figure will exceed 300 million by 2020. Nearly 30 million Americans, representing almost 9% of the entire population, are living with diabetes. Of these, approximately 25% have not been diagnosed. The ADA projects that by the year 2050, there will be approximately 87 million people with type 2 diabetes in the United States. The disease affects 15.9% of Native Americans and Alaska Natives, 13.2% of blacks, 12.8% of Hispanics, and 7.6% of whites. Diabetes mellitus accounts for about 79,000 deaths per year and is the seventh most common cause of death in the United States.
Type 2 disease is the most prevalent type of diabetes mellitus. Of patients with diabetes in the United States, more than 90% have type 2 disease. The incidence of type 2 diabetes increases with age and is primarily an adult disease. In contrast, type 1 diabetes occurs in 0.3% of Americans but is more than four times more prevalent than type 2 diabetes in persons younger than 20 years of age. Currently, there are about 26 million persons with type 2 disease (90%) and about 4 million with type 1 disease (10%).
The prevalence of diabetes mellitus has increased more than sixfold in the United States over the past 3 decades. The major reason for the dramatic increase is the obesity epidemic, especially in relation to type 2 diabetes. Recent reports indicate that more than 60% of patients with type 2 diabetes are obese at the time of diagnosis, and more than two thirds of U.S. adults are overweight or obese. Obesity is a major factor in the continual rise in the number of cases of diabetes in the United States. Other factors associated with the increasing prevalence of diabetes are the increasing population, increasing life expectancy, and increasing number of affected persons who have offspring who will pass on the disease.
Etiology
Type 1 diabetes is primarily the result of pancreatic beta cell destruction and is characterized by insulin deficiency. Type 2 diabetes is characterized by insulin resistance and relative insulin deficiency. The broad category of other specific types (see Box 14.1 ) comprises more than 56 pathologic conditions that are attributed to genetic defects in beta cell function, as well as diseases or infections that cause diabetes. Gestational diabetes is abnormal glucose tolerance that first appears or is detected during pregnancy. In addition, there are two types of prediabetes: impaired glucose tolerance and impaired fasting glucose. Persons who have abnormal blood glucose levels that are not high enough to be classified as diabetes are assigned a diagnosis of prediabetes. Fig. 14.1 illustrates the disorders of glycemia according to etiologic types.
