Health Library: Diabetes

Last updated: December 27, 2020

Understanding diabetes is very important because it is a chronic disease that, if well managed, can allow an almost normal life. If uncontrolled, it can be the cause of life-threatening complications. An essential feature of diabetes is high blood glucose levels. The body’s hormone which checks glucose levels is insulin. This hormone lowers blood glucose levels by promoting its uptake by tissues to use as a fuel. When insulin production is diminished or tissues become resistant to its effect, diabetes occurs.

The National Diabetes Statistics Report states that over 29 million Americans have diabetes. That is quite significant as it means that almost every tenth person is affected. Studies have also shown that it is the seventh leading cause of death, and even those individuals who do not die directly because of diabetes may find their life expectancy reduced by several years. Additionally, the risk of heart disease is doubled and diabetes can cause some fearsome complications such as kidney failure, blindness, and lower-limb amputations. Diabetes continues to be rising despite the billions of dollars that are spent every year on related healthcare and treatments.

Classification of diabetes

Type 1 diabetes

Type 1 diabetes is considered an autoimmune disease with a hereditary component that manifests in children and young adults. Its main characteristic is the complete absence of the pancreatic cells that produce a hormone called insulin, without insulin it is impossible for glucose to get into the body cells, causing sugar to build up in the bloodstream.

Even though there’s no definitive cure, type 1 diabetes is mostly manageable, and recent studies have improved the life expectancy of people suffering from this condition. Treatment focuses on managing blood sugar levels with insulin, diet, and a healthy lifestyle to prevent complications. There's no known way to prevent type 1 diabetes.

Type 2 diabetes

Type 2 diabetes happens when the body cannot properly produce and use the insulin hormone, this is called “insulin resistance”, which means that the different body tissues and organs are not affected by the amount of insulin produced by the pancreas, which by itself, have to constantly produce more and more to keep up with the constantly rising glucose levels, to no avail. As opposed to type 1 diabetes, this type of disease is an “acquired” one, affecting only people with some risk factors, these being obesity, unhealthy dieting, and physical inactivity. There is also a minor hereditary factor related to this disease as well.

Diabetes symptoms

Diabetes symptoms have some variations whether it’s type 1 or 2, the more common symptoms between the two include increased thirst (polydipsia), frequent urination (polyuria), excessive appetite or eating (polyphagia), irritability, fatigue or weakness, blurred vision, and slow healing bruises or cuts. Differences between type 1 and type 2 diabetes are mainly due to weight, in the case of the type 1 disease, there’s an unexplained weight loss, and in the case of the type 2, the weight loss is hardly noticeable due to the lifestyle that the patient usually has.

Symptoms can be fairly subtle, so it is unsurprising that many people don't realize that they have diabetes for a long time. This is especially true for type 2 diabetes, which is the more common form of the disease. This also means that many people may be first diagnosed when they are present with the symptoms of a complication. People who are overweight or obese are more prone to developing type 2 diabetes. Losing weight through a healthy diet and sufficient exercise can significantly reduce this risk. Family history and ethnicity are types of risk factors that cannot be controlled but individuals can reduce their overall risk of diabetes by maintaining a healthy lifestyle.

Diabetes diagnosis

The goals of diabetes testing are to screen for high blood glucose levels (hyperglycemia), to detect and diagnose diabetes and prediabetes, to monitor and control glucose levels over time, and to detect and monitor complications in already diagnosed people.

A physician can test for diabetes when someone has signs and symptoms suggestive of the disease, when a person has risk factors or a condition that is associated with diabetes, when a person presents to the emergency room with an acute condition, or on a regular basis to monitor diabetes and glucose control.

According to the American Diabetes Association, several different tests may be used for screening and diagnosing diabetes or prediabetes. If the initial screening result is abnormal, the test is repeated on another day. The repeat result must be abnormal to confirm a diagnosis of diabetes. Tests include:

  • Fasting glucose (fasting blood glucose, FBG) — this test measures the level of glucose in the blood after an 8–12 hour fast.
  • A1c (also called hemoglobin A1c or glycohemoglobin) — this test evaluates the average amount of glucose in the blood over the last 2 to 3 months.
  • 2-hour glucose tolerance test (OGTT) — this test involves drawing a fasting blood test, followed by having a person drink a 75-gram glucose drink and then drawing another sample two hours after consuming the glucose.

Diabetes treatment

Maintaining your blood sugar levels within the range recommended by your doctor can be challenging. That's because many things make your blood sugar levels change, sometimes abruptly. Keeping track of the food you ingest, making healthy food choices, avoiding sugar-sweetened beverages, and exercising regularly, are primordial steps to keep your diabetes controlled.

For diabetes type 1, several types of insulin are available. Each type starts to work at a different speed, known as “onset,” and its effects last a different length of time, known as “duration.” Most types of insulin reach a peak, which is when they have the strongest effect. Then the effects of the insulin wear off over the next few hours or so.

For type 2 diabetes, you may need medicines along with healthy eating and physical activity habits to manage your disease. Most people with type 2 diabetes start medical treatment with metformin pills. Metformin lowers the amount of glucose that your liver makes and helps your body use insulin better. Other oral medicines act in different ways to lower blood glucose levels. You may need to add another diabetes medicine after a while or use a combination treatment. In some cases, insulin injections will be necessary to manage your glucose levels.

If you want to learn more about this disease, you can check the links provided below:

What is diabetes?

  • Introduction to diabetes: Look through a collection of resources on topics ranging from prediabetes to the main types of diabetes, what to do when diagnosed, and how to manage diabetes in children and pregnant women.
  • An overview of diabetes: Patients and their family members can get an overview of the disease and read about several emerging issues. This resource is provided by the government's Healthy People program.
  • Diabetes facts: For some fast information about diabetes, consult this virtual fact sheet from Answers to common questions and concerns are offered, with real stories of how patients learned to manage their diabetes.
  • An explanation of diabetes: This article from the New York Times' Health Guide provides readers with a description of diabetes causes, symptoms, treatment, and prevention.
  • Diabetes glossary: If you or a loved one has received a recent diagnosis of diabetes, have a look through this glossary from the CDC to understand some of the words and terms commonly used in discussing this disorder.
  • Diabetes resource: To learn about diabetes, have a look at this comprehensive online resource from the CDC. It covers questions about diabetes, statistics and trends, related medical news, and educational articles for patients and professionals.
  • Guide to diabetes: Find out all about diabetes, its statistics, ongoing research, and related resources. The information is supplied by the government's Department of Health and Human Services.

Symptoms and diagnosis

  • Diabetes symptoms: The national institute of Diabetes provides a basic list of symptoms that diabetic patients can expect. If you have been experiencing changes in your health, this list is worth consulting.
  • When to be concerned: Since diabetes symptoms are not always very distinct, the Mayo Clinic has prepared a guide to consult. It describes symptoms which manifest more strongly and suggests when to see a doctor.
  • Diabetes for first-time patients: New diabetes patients will undoubtedly benefit from this reassuring guide compiled by the ADA. It fully discusses how to live well with type 1 or 2 diabetes.
  • Testing methods: Before being tested for diabetes, it can be helpful for patients and their family members to browse through this overview of diabetes testing methods from the American Association for Clinical Chemistry (AACC).
  • Diagnosing diabetes: This link offers plenty of information to patients regarding the ways in which diabetes is diagnosed and managed.
  • Glucose tests: The AACC has prepared this useful guide for people who have been recently diagnosed with diabetes. It describes glucose tests and how to interpret the results.

Risk factors, prevention, and screening

  • Type 2 diabetes risk test: Just about anyone can benefit from the ADA's virtual diabetes risk test. It only takes a couple of minutes to complete but can effectively point out an individual's risk for the disease.
  • Lowering the risk of diabetes: You can learn more about type 2 diabetes from the NDIC website and find out how to reduce or eliminate your risk.
  • Preventing type 2 diabetes: outlines simple but effective steps to prevent diabetes or delay it. Some of the steps are maintaining an active lifestyle and healthy diet and lowering cholesterol levels.
  • How to take control: The Mayo Clinic shares some great tips for diabetes prevention.
  • Diabetes prevention program (DPP): The NDIC discusses the results of a large multicenter study that indicate that type 2 diabetes is preventable through weight loss and physical activity.

Diabetes greatly increases the risk of stroke. Healthcare providers will learn what to do in the suspected stroke algorithm, but it is still important for everyone to recognize the signs and know the importance of acting immediately.

Disease management and treatment

  • What happens after diagnosis: People who have been diagnosed with diabetes can consult the National Diabetes Education Program (NDEP) through this link to learn how to manage it and prevent complications.
  • Managing diabetes: This Mayo Clinic article describes how diabetes requires many life changes for proper management. Examples of these are changes to one's diet, activity levels, schedules, and medication.
  • Checking blood sugar levels: This is a detailed guide on checking blood sugar levels. It lists the supplies needed and describes how to perform the test.
  • Devices for checking blood glucose: Before purchasing blood glucose testing devices, do grasp the information presented in this article by the FDA.
  • Your glucose meter: New patients can read this guide to learn about glucose meter and some helpful tips for testing blood sugar.
  • Tight diabetes control: What does tight control mean? What are its advantages? Are there any disadvantages? Check this link to find the answers.
  • Staying active with diabetes: Diabetics who lead sedentary lifestyles should read through this article by the NDIC to find out how exercise can improve their condition and where they can start.
  • Diabetes and holidays: During holidays and special festivals, it can be difficult to refrain from eating treats and sweet foods. The CDC discusses this issue and offers helpful tips to diabetics on how to manage on such occasions.
  • 4 steps to manage your diabetes for life.


  • Coping after being diagnosed: The time immediately after the diagnosis can be quite traumatic and stressful for many people. A valuable collection of resources from the ADA offers information on how to get through it, along with articles for family members and caregivers so that they may help the patient through this crucial time.
  • Helping a loved one cope with diabetes: Learn how to help a loved one cope with their condition from this insightful article by the NDEP.
  • Living with diabetes: While many diabetics may feel alone after their diagnosis, it helps to hear about coping strategies from others with the same disease. This blog on the Mayo Clinic site discusses how to cope with diabetes and manage it successfully.
  • Anger and diabetes: A common emotion that arises when someone is diagnosed with diabetes is anger. The ADA explains why it occurs and how people can use that emotion in a positive manner.
  • Stress and diabetes: Just as stress affects people on a regular basis, it can also affect diabetics. Unfortunately, however, it can further complicate their condition. Check this link to find out about the symptoms of stress and how to cope with it.
  • Managing stress when you have diabetes: Diabetics should be careful to reduce their stress levels and try to control it as much as possible. WebMD offers some great tips to tame stress.
This page is written by on Jan 14, 2016.
This page is last reviewed and updated by on Jun 22, 2020.