DIABETES MELLITIS: TYPE 1 AND TYPE 2

Diabetes mellitus is a group of metabolic diseases characterized by elevated blood glucose levels (hyperglycemia) resulting from defects in insulin secretion, insulin action or both. Insulin is a hormone manufactured by the beta cells of the pancreas, which is required to utilize glucose from digested food as an energy source. Chronic hyperglycemia is associated with microvascular and macrovascular complications that can lead to visual impairment, blindness, kidney disease, nerve damage, amputations, heart disease, and stroke. In 1997 an estimated 4.5% of the US population had diabetes.

Direct and indirect health care expenses were estimated at $98 billion.1

The type of diabetes is based on the presumed etiology. This chapter provides information about the two most common types of diabetes: type 1 and type 2 diabetes (see Table 1).

TABLE 1

Characteristics of the Common Types of Diabetes

		Type 1	Type 2
	Age	Childhood	Pubertal
	Onset	Acute; severe	Mild-severe; often insidious
	Insulin secretion	Very low	Variable
	Insulin sensitivity	Normal	Decreased
	Insulin dependence	Permanent	Temporary; may occur later
	Racial/ethnic groups at increased risk	All (low in Asians)	African Americans, Hispanics, Native Americans, Asian/Pacific Islanders
	Genetics	Polygenic	Polygenic
	Proportion of those with diabetes	80%	10%-20%
	Association: obesity	No	Strong
	Acanthosis nigricans	No	Yes
	Autoimmune etiology	Yes	No

Source: Adapted from Orr, DP. Contemporary management of adolescents with diabetes mellitus. Part 1: Type 1 diabetes. Adolescent Health Update 2000;12(2), Table 2, p 3.

In type 1 diabetes, the body does not produce insulin, and daily insulin injections are required. Over 700,000 people in the United States have type 1 diabetes; this is 5-10% of all cases of diabetes mellitus. Type 1 diabetes is usually diagnosed during childhood or early adolescence and it affects about 1 in every 600 children.

Type 2 diabetes is the result of failure to produce sufficient insulin and insulin resistance. Elevated blood glucose levels are managed with reduced food intake, increased physical activity, and eventually oral medications or insulin. Type 2 diabetes is believed to affect more than 15 million adult Americans, 50% of whom are undiagnosed. It is typically diagnosed during adulthood. However with the increasing incidence of childhood obesity and concurrent insulin resistance, the number of children diagnosed with type 2 diabetes has also increased worldwide.2

For example, from 1982 to 1994 in one mid-western city, the proportion of children with type 2 diabetes increased from approximately 4% to 16%.3 This increase is greatest among individuals from certain ethnic/racial groups (African Americans, Native Americans, Hispanics and Asians/Pacific Islanders) and for those with a family history of type 2 diabetes.

Type 1 Diabetes

ETIOLOGY/CONTRIBUTING FACTORS

•         Caused by the immune destruction of the beta cells of the pancreas.

•         Antibodies to islet cells and insulin are present at diagnosis.

•         Insulin secretion gradually diminishes.

•         May present at any age, but most common in childhood and adolescence.

•         Insulin by injection is necessary for survival.

•         Contributing factors:

–        Genetic predisposition

–        Environmental triggers (infection or other stress)

Type 2 Diabetes

•         Caused by insulin resistance in the liver and skeletal muscle, increased glucose production in the liver, over production of free fatty acids by fat cells and relative insulin deficiency.

•         Insulin secretion decreases with gradual beta cell failure.

•         Reductions in blood glucose levels often can be achieved with changes in food intake and physical activity patterns. Oral medication and/or insulin injections are eventually required.

•         Contributing factors:

–        Obesity

–        Age (onset of puberty is associated with increased insulin resistance)

–        Lack of physical activity

–        Genetic predisposition

–        Racial/ethnic background (African American, Native American, Hispanic and Asian/Pacific Islander)

–        Conditions associated with insulin resistance, (e.g., polycystic ovary syndrome).

TO BE CONTINUE Next Post.

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