What Causes Diabetes?

All forms of diabetes, whether type 1, type 2, or gestational diabetes, impact blood sugar levels. But what causes diabetes varies, depending on the type.

Insulin, a hormone made by the pancreas, moves glucose from food into your body’s cells, where it’s used for energy. If your body cannot produce adequate insulin — or if cells are resistant to insulin — glucose (also known as blood sugar) rises and becomes abnormally, and sometimes dangerously, high. The result is diabetes.

However, while it’s true elevated glucose is the key marker of diabetes, it’s not what causes diabetes in the first place. Instead, what causes diabetes depends on the type of diabetes you have.

Although there are some rare forms of the disease, the three main types of diabetes are type 1, type 2, and gestational diabetes — and all have different causes, the Centers for Disease Control and Prevention (CDC) points out.

YOU MIGHT ALSO LIKE: Our Type 1 Diabetes section

Type 1 diabetes causes

About five percent of Americans who have diabetes have the most serious form — type 1. It can develop in children, adolescents, and young adults, but type 1 diabetes occurs at every age, the American Diabetes Association explains. What a person weighs, their race, or other factors do not seem to play a role in type 1 diabetes causes.

Instead, type 1 diabetes is an autoimmune disease in which the body’s own immune system mistakenly attacks and destroys insulin-making cells in the pancreas, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). When this happens, your pancreas stops making insulin, glucose can’t enter cells, and blood glucose levels soar. In order to survive, people with type 1 diabetes must take insulin every day for the rest of their lives.

Type 1 diabetes causes may involve a genetic factor. Having a parent or sibling with the disease is known to increase the risks of developing type 1 diabetes. NIDDK experts think genes may interact with factors in the environment, such as certain viruses, to trigger the disease.

National Institutes of Health researchers are working on multiple studies with an international team of scientists to pinpoint type 1 diabetes causes, and possible ways to prevent the disease, through Type 1 Diabetes TrialNet.

Knowing what causes type 2 diabetes can help prevent it

A study by University of Iowa and Harvard researchers, published in the BMJ, found type 2 diabetes comprises over 91 percent of all cases of diabetes in the U.S. In fact, the CDC has called type 2 diabetes an epidemic.

In type 2 diabetes, your pancreas still produces insulin, but your body doesn’t use insulin normally. This results in blood sugar levels that are too high.

What causes diabetes of the type 2 variety is largely an unhealthy lifestyle. You are more likely to develop type 2 diabetes if you are overweight or obese and sedentary. That’s because extra weight, especially a “spare tire” around your middle, is associated with insulin resistance - which means your pancreas is still producing insulin, but your body has become resistant to the hormone. Glucose then builds up in the blood instead of being absorbed by cells, resulting in prediabetes and, eventually, type 2 diabetes, according to the NDDK.

Genes may also play a role in causing type 2 diabetes, or at least in raising the odds you may develop the disease. Type 2 diabetes tends to “run” in families, and it occurs more frequently in African Americans, Native Americans, Hispanics, Asian Americans, and Pacific Islanders.

The good news about type 2 diabetes is you can take steps to prevent the disease with healthy lifestyle changes, such as losing excess pounds if you’re overweight, sticking to a healthy diet rich in vegetables and fruits and low in processed foods, and getting regular physical activity.

What causes diabetes in pregnancy?

Gestational diabetes is a type of diabetes that develops only during pregnancy, usually around the 24^th week. Approximately nine percent of American women develop this condition while they are expecting, according to a CDC report.

The exact cause of gestational diabetes isn’t known, but it appears to be related to hormonal changes that make insulin resistance more likely, according to the American Diabetes Association. Genes and being overweight may also play a role in developing diabetes during pregnancy.

Gestational diabetes can increase your risk of high blood pressure, making it more likely your baby will need to be delivered by cesarean section (C-section), the CDC notes — so it’s important to work with your doctor to manage gestational diabetes. A healthy eating plan and getting appropriate, regular exercise can help. If physical activity and a nutritious diet aren’t enough to control blood glucose, you may need insulin.

Gestational diabetes typically goes away after you give birth. However, about half of women who experience gestational diabetes eventually develop type 2 diabetes. To lower your risk, work on achieving a healthy body weight after delivery.

YOU MIGHT ALSO LIKE: Our Type 2 Diabetes section