Diabetes
June 22, 2026
This page was reviewed under our medical and editorial policy by Ping H. Wang, M.D., Professor and Chair, Department of Diabetes, Endocrinology & Metabolism, City of Hope®Duarte Cancer Center.
Diabetes is a chronic health condition that affects the body’s insulin production or response, leading to elevated blood sugar levels. About 38.4 million people live with the condition in the United States, according to the U.S. Centers for Disease Control and Prevention (CDC), and almost 1 in 5 people with cancer also have diabetes, notes the CDC.
Diabetes is also known as diabetes mellitus (DM), and it is considered a metabolic condition. This means that it impacts the body’s ability to produce energy from the foods that people eat.
Diabetes is a chronic condition and occurs when there is too much glucose (sugar) circulating in the blood. Glucose comes from the food you eat, and the body makes some of it, too. Normally, insulin promotes blood glucose transport into cells, keeping blood glucose levels in check. A high blood sugar level is called hyperglycemia, a telltale sign of diabetes. This blood sugar imbalance is due to not enough insulin being produced in the pancreas or a reduced sensitivity to insulin by cells in the body. This reduced sensitivity is also called insulin resistance.
While everyone is different, diabetes has some common symptoms to look out for. Increased blood sugar levels — a hallmark of the condition — may cause thirst, fatigue, headaches, blurry vision and diabetic neuropathy (nerve damage). This nerve damage may lead to tingling, pain or numbness in the feet and hands, frequent urination and sexual problems. In severe cases, patients may experience nausea, vomiting and feeling ill. Unexplained weight loss may also result from diabetes. In addition, changes in immune responses that accompany diabetes have been shown to decrease wound-healing abilities.
There are several types of diabetes. Type 2 diabetes makes up the majority of cases in adults, and type 1 diabetes is a common type in children and young adults. In type 1 diabetes, the cells that make insulin are destroyed by the immune system. This means a person’s pancreas produces little to no insulin, and he or she must take insulin daily to keep blood sugar levels from rising. In type 2 diabetes, the muscle, fat and liver cells are not as sensitive to insulin’s attempts to move blood sugar into cells, which leads to high blood sugar. There are also some less common types of diabetes.
Insulin injections are used to treat type 1 diabetes, and they may also be recommended for patients with type 2 diabetes. Other medicines may be prescribed to lower blood sugar levels, improve existing insulin or regulate digestion so blood sugar does not spike after eating or drinking. A healthy diet and frequent exercise are also essential. Weight-loss medications or surgery may be an option for certain patients. Regular blood sugar monitoring is important for both types of diabetes.
Some complications may occur due to chronic high blood sugar, such as diabetic neuropathy (nerve damage) and damage to blood vessels. These may lead to heart or kidney disease, stroke, skin infections, eye disease, sexual problems, bladder issues and foot problems such as pain, numbness or a delay in wound healing. A life-threatening condition called diabetic ketoacidosis may arise when excessive amounts of ketones build up quickly, leading to metabolic chaos.
City of Hope is a recognized leader in diabetes research. We have a long legacy of offering access to numerous clinical trials and new therapies that are not readily available elsewhere.
When you come to City of Hope, you automatically gain access to an unparalleled array of support services to help you and your loved ones take each step during and after a diabetes diagnosis.
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City of Hope is home to the Arthur Riggs Diabetes & Metabolism Research Institute, one of the world’s foremost scientific organizations dedicated to diabetes research.
Our developments in breakthrough diabetes treatments are recognized internationally.
City of Hope’s expert-led diabetes treatment team is dedicated to the singular goal of helping patients live better with this condition.