Causes of Diabetes

Author: Judy Kohn, RN, BSN, CDE

Last Updated: Tuesday, October 03, 2006

Q: "How do you get diabetes and is it genetic?"

A: Since you didn't mention what type of diabetes you have, I'll discuss each type and possible causes. What you will learn is that there are different types of diabetes, genetics may play a role, but the causes can vary, and the definite cause is still somewhat unknown.

In Type 1 Diabetes, the body does not produce insulin, so you must inject insulin daily. It generally occurs in people under age 40 (half of all people with type 1 are under age 20). The onset is usually sudden, with signs and symptoms of frequent urination, unusual thirst and hunger, weight loss, the presence of ketones in the urine, and sometimes ketoacidosis with coma.

Causes of Type 1 Diabetes:

• Autoimmune response: For unknown reasons, in some people the immune system mistakenly destroys the insulin producing cells (called beta cells) in the pancreas. It is thought that some people inherit genes that mistakenly tell the body to recognize its beta cells as foreign invaders; then, when one gets the flu or some type of virus, as the body is busy killing the foreign virus, it also kills its own beta cells because it mistakenly thinks the beta cells are invaders as well. Researchers have learned that there are certain types of gene combinations that predispose some people to type 1 diabetes.
• Oxygen free radicals: These are formed as a by-product of chemical reactions in the body, from exposure to smoke, air pollution, diet, and other things. Some researchers believe that oxygen free radicals could contribute to the destruction of pancreatic cells.
• Chemicals and drugs: There are certain rare drugs that can cause diabetes.

It is unlikely that genetics or environment alone cause diabetes. But likely a person could inherit a genetic susceptibility; then, exposure to some environmental factor might trigger the development of diabetes.

In Type 2 Diabetes, either the body doesn't produce enough insulin, or the body does not respond appropriately to the insulin (called insulin resistance).

Causes of Type 2 Diabetes:

• Genetics: Researchers aren't sure how, but some people inherit the genetic tendency to diabetes. Genetics is more common in type 2 than in type 1. If a person with type 1 has an identical twin, there is a 25 to 50 percent chance that the twin will develop diabetes; if a person with type 2 diabetes has an identical twin, there is a 60 to 75 percent chance that the person will develop diabetes. Certain cultures have more diabetes: African Americans, Asian Americans, Hispanic Americans and Native Americans.
• Insulin resistance: Researchers are still looking for the cause of insulin resistance, but in essence either there are not enough receptors on the cell, or the receptors aren't responding properly.
• Aging, obesity, and lifestyle: Obesity is much more common in diabetes, and there may be a genetic cause for obesity. We know from recent results of the Diabetes Prevention Trial that lifestyle changes (modest weight reduction and moderate regular exercise) can prevent the development of type 2 diabetes in some people. Age is also a factor, partly due to the fact that as people age, they might become more overweight and more sedentary, although that is not always the case; some people simply inherit the defect that causes their pancreas to decrease insulin production as they age. While statistics report that 7% of the U.S. population has diabetes, those numbers rise to up to 20% of people over age 65 have type 2 diabetes.

Gestational Diabetes is diabetes that occurs in 3-5% of pregnant women. Just like the other types of diabetes, the exact cause is unknown.

Causes of Gestational Diabetes

• Hormones: During pregnancy, the placenta produces hormones important for the baby's growth; but these hormones cause some insulin resistance and make the body resemble that of a person with type 2 diabetes.
• Genetics: Researchers suspect that the genes responsible for type 2 diabetes and gestational diabetes may be similar.
• Obesity: Gestational diabetes is more common in women who are obese.

As you can see, diabetes is a complicated condition to understand, and the causes are still somewhat unknown. You can read more details about this topic in the reference source I used: The American Diabetes Association'sComplete Guide to Diabetes .

Related Questions

Insulin Resistance
Q: "Could you explain insulin resistance so that I can understand it? This term seems confusing to me."

Related Links

American Diabetes Association (ADA)
http://www.diabetes.org

DOC09372-Rev-A 01/07