What is Diabetes?
Diabetes (also called diabetes mellitus) is a health condition that causes blood glucose (blood sugar) to become too high. Diabetes is diagnosed when a fasting blood glucose (sugar) level is 126 milligrams per deciliter (mg/dL) or higher.
How diabetes develops
When you eat, your body breaks down food into sugar (called glucose). This sugar enters your blood stream and is used by your cells for energy. To move sugar from the blood into your cells, your body uses a hormone, called insulin. Insulin is made by the pancreas, an organ near your stomach.
If your body doesn’t make enough insulin or cannot use insulin well, sugar builds up in the blood instead of getting into the cells. When this happens:
- The body’s cells don’t get the energy they need.
- Fat levels in the blood may increase
- Over time, high blood sugar can damage the eyes, kidneys, nerves and heart.
How Diabetes Affects Heart, Kidney and Metabolic Health (CKM health)
Doctors now understand that diabetes, obesity, heart disease and kidney disease are closely connected. This connection is called cardiovascular-kidney-metabolic (how the body creates, stores and uses energy) health (CKM Health).
When blood sugar stays high for a long time, it can place extra strain on the heart, damage blood vessels and harm the kidneys. Trouble in one area can make problems in the others more likely.
The good news is that many of the same healthy habits, like eating well, staying active, managing blood sugar and controlling blood pressure can help protect all three areas at the same time.
Types of diabetes
Type 1 diabetes
Type 1 diabetes happens when the immune system attacks the pancreas and destroys the cells that make insulin. People living with Type 1 diabetes make little or no insulin and must take insulin every day to replace what the body cannot make.
Type 1 diabetes is often diagnosed in children and young adults, but it can happen at any age. Having a family history of Type 1 diabetes raises risk. At this time there is no known way to prevent it.
Without insulin, blood sugar rises quickly and can cause serious health problems over time.
Learn more about the health consequences of diabetes and how to treat it.
Type 2 diabetes
Type 2 diabetes is the most common type. It happens when the body becomes insulin resistant, meaning it doesn’t use insulin well. Over time, the pancreas may also make less insulin.
Type 2 diabetes has typically been diagnosed in adults, but more teens and young adults are now developing it. This is linked to family history, lower physical activity and higher rates of excess weight.
Diabetes can develop slowly and may not cause symptoms for years. If untreated, it can lead to serious health problems, including heart disease and stroke.
Healthy eating, regular physical activity and weight management can delay or help manage Type 2 diabetes.
Except for diabetes that happens during pregnancy (called gestational diabetes), diabetes is usually a lifelong condition that needs ongoing care. Following your healthcare professional’s advice and taking medications as directed are important steps in staying healthy.
Learn more about the risk factors and what you can do to live your longest and healthiest life.
Precursors to diabetes
Insulin resistance
Insulin resistance means your body makes insulin, but your cells don’t respond to it well. This causes blood sugar to rise. To help, the pancreas makes more insulin. Over time, it may not be able to keep up, and blood sugar levels rise.
Insulin resistance may be present when a fasting person has:
- High blood sugar (hyperglycemia), or
- High insulin levels (hyperinsulinemia)
Insulin resistance affects more than just blood sugar. It can also raise the risk of heart disease and kidney disease.
Because these conditions are connected, healthcare professionals focus on keeping the heart, kidneys and blood sugar healthy together. Catching problems early can help prevent more serious issues later.
Health risks of insulin resistance
People living with insulin resistance have a higher risk of developing prediabetes, Type 2 diabetes and cardiovascular disease.
People living with insulin resistance are more likely to have a history of excess weight and low physical activity. They are also likely to have other cardiovascular risk factors such as high cholesterol and high blood pressure.
Additional risk factors for insulin resistance include:
- Age 45 or older
- Family history of diabetes
- History of gestational diabetes, heart disease or stroke
- Polycystic ovary syndrome (PCOS)
- Being Black American, Alaska Native, Native American, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander American
Some medications and hormone or sleep disorders can also increase risk.
Knowing your risk gives you a chance to take steps early to protect your health.
Prediabetes
Prediabetes means your blood sugar is higher than normal, but not high enough to be diagnosed as Type 2 diabetes.
If you’ve been told that you have prediabetes, you can lower your risk of developing Type 2 diabetes by:
Even small changes can make a big difference. Working with your healthcare team can help you create a plan that fits your life and supports your long-term health.
Learn more about prediabetes.
