What Causes Diabetes?
Doctors and health researchers don’t fully know what causes diabetes mellitus. They know what happens in diabetes, and they’ve identified potential risk factors, especially for type 2 diabetes, but the causes of diabetes remain rather elusive. Health professionals aren’t completely in the dark regarding diabetes causes, though. There are sound theories, and research into what causes diabetes mellitus is ongoing. Here’s a look at factors that have been identified as possible causes of diabetes.
Knowing Diabetes Causes Means Knowing What Happens in Diabetes
Diabetes has three primary forms:
- Type 1
- Type 2
Diabetes involves hyperglycemia, or high blood glucose (sugar) levels. Under healthy circumstances, carbohydrates you eat are digested into sugar that the cells of the body need for energy. Glucose can’t enter the cells by itself but needs a hormone called insulin, produced in the pancreas, to open a path into the cells. In all types of diabetes, there’s a problem with the function of insulin and glucose can’t get into the cells. It accumulates in the bloodstream which results in hyperglycemia.
This is what happens in diabetes. An important question is why does it happen? What are the causes of diabetes? The causes discussed below are potential causes of diabetes in children and causes of diabetes in adults. Type 1 diabetes most commonly develops by the 20’s and type 2 has a higher rate of onset over the age of 45, but both types of diabetes can develop at any age and thus the causes apply to all ages.
Possible Type 1 Diabetes Causes
Type 1 diabetes is an autoimmune disorder. It develops when the body’s immune system attacks the pancreas, the organ that produces insulin. Once the insulin-producing beta cells within the pancreas are destroyed, they don’t come back. The body is unable to make the insulin it needs to move blood sugar into cells.
Destruction of the pancreas’s beta cells by the immune system is the direct cause of type 1 diabetes. But why does the immune system turn on its own body? Possible type 1 diabetes causes are
- Genetic predisposition
- Exposure to some viruses, such as mumps or coxsackie
- Exposure to certain environmental toxins
Possible Causes of Diabetes Type 2
Type 2 diabetes isn’t an autoimmune disorder but instead develops due largely to external factors ("What Is the Difference Between Type 1 and Type 2 Diabetes?"). In type 2, the pancreas does produce insulin, but either it doesn’t make enough insulin to do the job, or the body doesn’t use it efficiently.
Doctors know some potential type 2 diabetes causes, but because more study is needed, they are hesitant to declare them as definitive causes. Instead, these are considered risk factors. If someone has any of these factors, he or she is at risk of diabetes:
- Being overweight or obese
- Poor diet low in nutrition, high in processed, fatty, sugary foods and drinks
- Sedentary lifestyle
- Family history of diabetes
Possible Gestational Diabetes Causes
Gestational diabetes is a temporary form of diabetes that develops during pregnancy and disappears within six weeks after delivery. While it’s unclear why it happens, the cause of gestational diabetes is hormonal. The placenta (the organ that nourishes the baby during development) makes a hormone that makes it difficult for the mother’s body to absorb glucose. In gestational diabetes, the mother’s pancreas doesn’t make the extra insulin required to compensate for the hormones secreted by the placenta.
Medications Causing Diabetes
In addition to the three primary types of diabetes, there are extremely rare forms that have different causes. Many of these are develop from drugs causing diabetes.
Some medications decrease the body’s ability to control blood sugar by causing insulin resistance or interfering in insulin secretion. Examples of medications causing diabetes include:
- Cardiovascular medications (thiazide diuretics, beta-blockers, and statins)
- Steroids known as glucosteroids (not the performance-enhancing steroids)
- Antipsychotics and atypical antipsychotics (common types of psychiatric medications)
- Immunosuppressive agents (used in organ transplants)
- Protease inhibitors (HIV medication)
- Pentamide (for certain types of pneumonia)
Because of the medications used, a disease called diabetes insipidus warrants mentioning. Despite its name, it’s unrelated to diabetes mellitus. The diseases share the name “diabetes” because of the increased urination and excessive thirst that are part of each illness.
Drugs causing diabetes insipidus include the antiviral medications cidofovir and foscamet (Foscavir) as well as lithium. Lithium is a medication used to treat bipolar disorder, depression, schizophrenia, eating disorders, and the aggressive behavior that is sometimes part of attention-deficit hyperactivity disorder (ADHD). Lithium treats many other non-psychiatric conditions, too. People taking lithium should have their blood checked approximately every six months (intervals vary).
Diabetes is a disease that can cause other serious health problems such as heart disease, nerve damage (which can lead to foot and even leg amputations), blindness, and kidney failure. Diabetes is the sixth leading cause of death in the Unites States (Judd, 2011). Therefore, researchers are seeking the cause. Knowing the cause can help people stop diabetes before it starts.
Last Updated: 09 January 2019
Reviewed by Harry Croft, MD