Causes of Diabetes

Causes of Diabetes

Risk Factors for Diabetes Mellitus 

• Family history of diabetes

• Obesity

• Race (native American, Hispanic, or African- American) – in relation to their lifestyle and diet preference

• Age (40 years old and above)

• Intake of medications (glucocorticoids)

• Women (history of gestational diabetes mellitus or deliveries of babies > 9 pounds)

• Sex ( females are more prone than men)

• Endocrine disorders

The genetic implications in the development of diabetes have long been recognized, but there is little agreement about the nature of the genetic mechanisms involved. Diabetes was once considered to be transmitted as a Mendelian single autosomal recessive trait. One genetic trait may give rise to the metabolic derangement of insulin deficiency while another causes the premature vascular disease. Although these traits are independent of one another, they coexist. Genetic counseling is still not recommended because of the unknown nature of the pattern of transmission. It is important that persons with diabetes are made aware of the familial tendencies and risks for siblings of the individual with either type of diabetes, and that they be discussed.

Obesity has long been discussed in association with diabetes, specifically the Non- Insulin Dependent Diabetes Mellitus (NIDDM). Overweight persons are especially susceptible to diabetes. Enlarged fat cells are less responsive to insulin, and glucose uptake by them is lessened. This decrease in the use of insulin by fat cells combines with excessive carbohydrate ingestion to increase the blood glucose level. To compensate, obese persons must hypersecrete insulin to sustain normal glucose metabolism. The risk of diabetes is reported to be greater in subjects with central adiposity of the trunk as contrasted to be equally fat persons who have more of their total fat in the subcutaneous depots of their extremities. Therefore, primary prevention should be directed toward lifestyle changes that include exercise, weight control or weight loss, and knowledge of risk factors. 

Carbohydrate intolerance increases with aging. Although no age group is spared, 80 percent of the diabetic population is more that 40 years old. If the plasma glucose values of 60 to 100 mg/dl are considered normal for the population as a whole, persons over the age of 40 will have a higher incidence of elevated blood glucose levels than younger persons.  Aging considers the decline in glucose tolerance as a pathologic process.

Some medications can induce hyperglycemia. Glucocorticoids do this by stimulating gluconeogenesis. The estrogen component of birth control pills also induces a resistance to the hypoglycemic effects of insulin. In some persons oral thiazides have a diabetogenic effect. The exact mechanism is unknown, but potassium has been shown to have a corrective effect.

Pregnancy can also precipitate diabetes. The variety of hormones elaborated by the placenta and the increased maternal levels of cortisol during gestation diminishes the effectiveness of insulin. The placenta also degrades maternal insulin. Women are at greater risk to developing diabetes than men. This is primarily related to their degree of adiposity.

Many endocrine disorders are associated with increase in blood glucose levels. An excess in growth hormone (as in acromegaly) and hypersecretion of the adrenal cortex (Cushing’s syndrome) causes hyperglycemia. Whatever the provoking circumstance, the functioning beta cells attempt to secrete insulin in a sufficient amount to decrease the blood glucose and maintain normal levels. Beta cells exhaustion follows and initiates a group of events that are closely connected that distorts the normal metabolic processes.