Diabetes is a group of health conditions that are defined by high blood sugar (glucose) levels. There are several forms of diabetes, all of which involve some dysfunction in the use or production of the hormone insulin, which allows the body to use sugar in the bloodstream for energy.
Though different types of diabetes have different causes, they tend to have similar symptoms and complications. There is no cure for diabetes, and some forms of the disease are lifelong, but all can be treated and managed with diet, exercise, and medication.
Every type of diabetes involves hyperglycemia (high blood glucose levels) caused by some form of insulin dysfunction. Glucose enters the body primarily through the food and beverages you consume. The pancreas makes a hormone called insulin to help the glucose in your blood enter your cells to be used for energy. Diabetes occurs when your body is not able to use insulin properly, cannot create enough insulin, or both. Glucose builds up in the bloodstream, damaging nerves and blood vessels throughout the body.
Type 2 Diabetes
Type 2 diabetes results from insulin resistance, an inability to use the hormone insulin properly. As the body’s demand for insulin increases, the pancreas may struggle to produce enough of the hormone to maintain healthy blood glucose levels.
The condition typically develops in people older than 45, but the incidence of type 2 diabetes in children is also on the rise.
Risk factors for type 2 diabetes include age, excess weight, a sedentary lifestyle, and a variety of other metabolic conditions such as high blood pressure.
There isn’t a cure for type 2 diabetes, but some people can put the condition into remission through diet, exercise habits, and weight loss. For most others, type 2 diabetes is a progressive disease, and the condition will worsen over time. It is typical to require more medication as you age.
Treatment options for type 2 diabetes vary based on your blood glucose and A1C levels but can include weight loss, lifestyle changes, medication, and bariatric surgery for those who also have obesity. Though type 2 diabetes may only have subtle symptoms at first, it can eventually lead to debilitating complications such as kidney disease, neuropathy, amputation, vision loss, and cardiovascular disease. Keeping your blood sugar within your target range and taking medications as prescribed will greatly reduce the risk of these bad outcomes.
Prediabetes
Prediabetes is not technically a form of diabetes, but it can lead to type 2 diabetes.
Almost 98 million adults in the United States have prediabetes, affecting 38 percent of the population. It’s experienced by nearly half of all adults older than 65.
Prediabetes has the same causes as type 2 diabetes; family history, advancing age, excess weight, and a sedentary lifestyle are among the known risk factors.
Prediabetes itself doesn’t typically lead to diabetes-related complications because blood glucose levels aren’t high enough to cause significant damage to nerves and blood vessels throughout the body. But a person with prediabetes has up to a 50 percent chance of developing type 2 diabetes within 10 years. When prediabetes progresses to type 2 diabetes, your healthcare team may recommend using medication to lower your blood sugar.
Not everyone with prediabetes will develop type 2 diabetes, and with intervention some people can reverse prediabetes. Losing just 7 percent of your body weight (15 pounds if you weigh 200 pounds) may lower your risk of type 2 diabetes by 58 percent.
People with prediabetes may benefit from metformin therapy, and recent research suggests GLP-1 and dual GLP-1/GIP receptor agonist medications like semaglutide and tirzepatide can help some people with prediabetes reverse the condition.
Type 1 Diabetes
Type 1 diabetes is an autoimmune disorder in which a person’s own immune system attacks and destroys the cells in the pancreas that make insulin. As natural insulin production declines, blood glucose levels can rise to life-threatening levels. The symptoms of type 1 diabetes can come on very quickly, especially in the young. Sometimes the condition isn’t identified until a patient has experienced a deadly condition named diabetic ketoacidosis (DKA).
People with type 1 diabetes must take insulin every day to replace the insulin their bodies don’t make, as well as monitor their blood glucose levels daily.
Type 1 diabetes affects about 5.7 percent of adults ages 20 and older with diagnosed diabetes in the United States.
This form of diabetes can occur at any age, contrary to outdated beliefs that it only develops during childhood. In fact, more than 50 percent of new type 1 diabetes cases are diagnosed in adults.
Type 1 diabetes is a lifelong chronic condition without a cure. With daily diligence taking insulin and monitoring blood glucose levels, a person with type 1 diabetes can live a full life. Advancements in insulin, insulin delivery technology, and blood glucose monitoring have significantly improved the quality of life of people with type 1 diabetes and their ability to maintain healthy blood glucose levels.
Despite these advancements, people with type 1 diabetes still face daily risks of hypoglycemia (low blood sugar), and blood sugar management can be a demanding balancing act.
Latent Autoimmune Diabetes in Adults (LADA, or Type 1.5 Diabetes)
Latent autoimmune diabetes in adults (LADA) is a subtype of type 1 diabetes that develops very slowly during adulthood. It’s often mistaken for and misdiagnosed as type 2 diabetes.
People with LADA may not need insulin for years. Instead, lifestyle changes and medications for type 2 diabetes, such as metformin or GLP-1s, may temporarily keep blood glucose levels in a healthy range.
As their natural insulin production declines, people with LADA tend to find that these early treatment methods are no longer effective. Ultimately, they need daily insulin therapy.
Generally, doctors diagnose LADA by testing for the presence of antibodies to pancreatic cells and C-peptide levels, which indicate how much insulin the pancreas is producing. In people with LADA, autoantibodies are identifiable and C-peptide levels are low.
People with LADA eventually need to follow guidelines pertaining to type 1 diabetes for ongoing management.
Maturity-Onset Diabetes of the Young (MODY)
Maturity-onset diabetes of the young (MODY) is a rare, inherited form of diabetes caused by mutuations in a particular gene that affects the body’s production of insulin.
While its symptoms are similar to those of other types of diabetes, MODY is fundamentally different from type 1 and type 2 diabetes.
MODY:
Typically develops during adolescence or early adulthood before age 25
Isn’t caused by the immune system or insulin resistance
Is frequently misdiagnosed as type 1 or type 2 diabetes
Is typically treated with non-insulin diabetes medications
If a parent has MODY, their child has a 50 percent risk of developing the condition. Genetic testing is key to obtaining an accurate diagnosis.
Neonatal Diabetes
Neonatal diabetes is a rare form of diabetes that develops within the first six months of a child's life. Unlike type 1 diabetes, it’s not caused by the immune system. Instead, it’s the result of genetic mutations that affect the body’s ability to produce insulin. Diagnosing neonatal diabetes accurately requires genetic testing.
Neonatal diabetes can be transient, which means it can resolve by itself, though it may possibly return later in life. It can also be permanent, requiring daily insulin therapy indefinitely.
Signs and symptoms of neonatal diabetes include:
Inadequate weight gain
Dehydration
High blood sugar
This form of diabetes can often be managed with type 2 diabetes medications, such as sulfonylureas, rather than insulin.
The earlier neonatal diabetes is diagnosed, the more likely long-term complications can be prevented.
Gestational Diabetes
Pregnant women develop gestational diabetes during about 14 percent of all pregnancies in the United States. To help ensure there’s enough glucose available to provide energy for a growing fetus, pregnant women normally develop a certain amount of insulin resistance, and sometimes this causes blood sugar to increase to the diabetic range.
Typically, treatment for gestational diabetes focuses on diet and lifestyle changes, but sometimes doctors prescribe oral diabetes medications or insulin to keep blood sugar in a healthy range.
Gestational diabetes can lead to complications that affect the health of both the mother and child. Women with gestational diabetes have a higher risk of preeclampsia, and their infants are more likely to be born prematurely or have a higher than normal birth weight, creating complications during delivery. The infants can also go on to develop dangerously low blood sugar levels soon after birth. Later in life, they have an increased risk of developing obesity, heart disease, and type 2 diabetes.
Gestational diabetes usually goes away after the child is born, but half of all women with the condition go on to develop type 2 diabetes within a few years of their pregnancy.
Type 3 Diabetes
Unlike the other types of diabetes mentioned, so-called “type 3 diabetes” isn’t an official diagnosis recognized by the medical community. Instead, it’s a research term referring to evidence that Alzheimer’s disease and other neurodegenerative conditions are linked to insulin resistance in the brain.
Diabetes may disrupt blood flow or create abnormal protein accumulations that lead to brain cell death and conditions such as cognitive impairment, dementia, Parkinson’s disease, and Alzheimer’s disease.
Type 3c Diabetes
Type 3c diabetes, also known as pancreatogenic or pancreatic diabetes, is caused by direct damage to the pancreas. This damage can be caused by conditions such as chronic pancreatitis or cystic fibrosis, or by surgical removal of the pancreas (pancreatectomy).
People with type 3c diabetes may also experience exocrine pancreatic insufficiency (EPI), an inability to produce normal amounts of digestive enzymes. Managing type 3c diabetes can include any combination of oral diabetes medications, non-insulin diabetes medications, insulin therapy, and pancreatic enzyme supplementation.
Steroid-Induced Diabetes
Steroid-induced diabetes is a form of diabetes caused by the use of glucocorticoids like prednisone. Also known as corticosteroids, these medications are commonly prescribed for conditions like asthma and arthritis. Steroids increase blood glucose levels by increasing the liver’s production of glucose and decreasing the body’s sensitivity to insulin. People without diabetes can develop diabetes as a result of taking corticosteroids. In some cases, ceasing to use steroids can resolve steroid-induced diabetes, but in other cases it is a permanent condition that will need to be treated similarly to type 2 diabetes.
The symptoms of diabetes are generally the same, regardless of the type of diabetes, because they are all caused by high blood sugar. They include:
Increased thirst
Increased hunger
Frequent urination
Unexplained weight loss
Fatigue
Blurred vision
Numbness or tingling in the hands or feet
Sores or cuts that heal slowly or not at all
Frequent infections
If you’re experiencing any combination of these symptoms, visit your doctor or urgent care center immediately for evaluation. Undiagnosed diabetes can be extremely dangerous.
Some forms of diabetes, including type 1 diabetes, LADA, MODY, neonatal diabetes, and type 3c diabetes, cannot be prevented. But you can take steps to lower your chance of developing types of diabetes that result from insulin resistance, such as prediabetes, type 2 diabetes, and gestational diabetes.
Diabetes Risk Factors: Where You Can Take Action
Some of the strongest risk factors for developing insulin resistance may be within your ability to manage and control:
Excess weight
A diet that’s high in fat, added sugar, and refined carbohydrates
Diabetes is diagnosed using one or more blood sugar tests.
Fasting Plasma Glucose Test
A fasting plasma glucose test is performed after a person has had nothing to eat for at least eight hours. Results fall into one of three categories:
Less than 100 milligrams per deciliter (mg/dL) is considered normal
100 to 125 mg/dL indicates prediabetes
126 mg/dL or higher indicates diabetes
Random Plasma Glucose Test
A random plasma glucose test for diabetes doesn’t require fasting beforehand. A blood sugar measurement of 200 mg/dL or higher suggests the presence of diabetes. This test is more difficult to interpret, though, because the results are so strongly influenced by what the person ate or drank in the hours prior to testing.
Hemoglobin A1C Test
A hemoglobin A1C test shows how much glucose attaches to a person’s red blood cells, on average, over a span of three months. You don’t have to fast before this test. Results fall into one of three categories:
Below 5.7 percent is considered normal
Between 5.7 and 6.4 percent indicates prediabetes
6.5 percent and higher indicates diabetes
Additional Testing
While blood sugar tests can reveal whether a person has diabetes, they cannot always identify the type of diabetes. A healthcare provider may choose to administer additional tests in order to determine if an individual has type 1 diabetes, type 2 diabetes, or a rarer form of the disease.
Autoantibody Tests These tests, which look for antibodies targeting insulin or certain pancreatic cells, are conducted most often to diagnose type 1 diabetes or LADA.
C-Peptide Test This test measures the amount of a protein that mirrors the level of insulin in the body, low levels of which can indicate type 1 diabetes or LADA.
Genetic Testing MODY and neonatal diabetes may be detected using genetic testing.
Sometimes these additional tests are administered long after an initial diabetes diagnosis, especially if treatment has proven ineffective.
If you’ve been diagnosed with diabetes, your treatment regimen will depend on your individual health and the type of diabetes you’re managing.
Blood Sugar Testing
Diabetes treatment is defined by blood sugar management, and it’s essential to measure and track your blood sugar levels if you want to understand your condition. You may be advised to check your blood sugar only occasionally, or multiple times every day, including before every meal.
A traditional glucose meter requires you to prick your finger with a lancing device, then place the blood drop on a disposable test strip that’s inserted into the meter. The meter will show you your current blood sugar level.
A newer tool, the continuous glucose monitor (CGM), automatically sends new blood sugar measurements to your smartphone or to a dedicated receiver device. A small sensor attaches to the skin for up to 14 days and samples your glucose levels around the clock, allowing for a far greater understanding of your blood sugar trends and changes.
The most advanced diabetes technology, known as automated insulin delivery (AID) or hybrid closed-loop systems, unites a CGM and an insulin pump to automatically sense your blood sugar levels and adjust your insulin dosage.
Insulin
Not everyone with diabetes requires insulin, but some people will require regular injections of the hormone in order to keep their blood sugar levels in a safe range.
Many people with type 1 diabetes will need insulin immediately and can expect to need it every day for the rest of their lives. People with LADA don’t need insulin when they are diagnosed, but will eventually develop an absolute need for insulin. Some people with other forms of diabetes, including type 2 diabetes, will also be prescribed insulin, though they may not need it as soon as they’re diagnosed.
Insulin therapy is typically self-administered by injection, up to several times a day, using a needle, syringe, pen, or pump.
Different types of insulin are categorized by how quickly they reduce blood sugar levels:
Basal insulin, or long-acting insulin, covers the body’s background insulin needs, working steadily over 24 hours. This may be the first type of insulin that you are prescribed.
Bolus insulin, also known as rapid-acting or mealtime insulin, lowers blood sugar levels quickly, and is most often before or during meals.
All types of insulin carry a danger of low blood sugar (hypoglycemia) and require training to be used safely.
DPP-4 inhibitors increase your pancreas’s natural insulin production after meals and tell your liver to produce less sugar by inhibiting the enzyme that breaks down your body’s endogenous GLP and GIP hormones.
GLP-1 receptor agonists mimic the hormone GLP-1 to lower blood sugar levels. They work in several ways, including decreasing appetite, increasing insulin sensitivity, delaying digestion, and decreasing liver glucose production. Weight loss is a known benefit, which further helps improve insulin sensitivity and blood glucose levels.
GLP-1/GIP receptor agonists work similarly to GLP-1 receptor agonist medications. They reduce blood glucose levels, improve insulin sensitivity, support weight loss, and regulate cholesterol levels.
Meglitinides tell the pancreas to produce more insulin when you’re eating.
Metformin works by telling the liver to produce less glucose and boosting insulin sensitivity.
SGLT2 inhibitors work by passing excess sugar from your bloodstream through your urine, requiring your kidneys to remove the extra sugar.
Sulfonylureas tell the pancreas to release more insulin with meals.
Thiazolidinediones improve your body's overall sensitivity to insulin.
Surgery
Weight loss surgeries can help some people with type 2 diabetes achieve remission. Gastric bypass surgery, one type of weight loss surgery often used to treat diabetes, works by modifying the digestive system to encourage rapid weight loss and improve insulin sensitivity. Gastric bypass surgery proves highly effective, with 75 percent of patients achieving and maintaining diabetes remission.
The American Diabetes Association recommends metabolic surgery for people with type 2 diabetes who meet specific criteria, including a high BMI and difficulty managing blood sugar levels with traditional treatment options.
While some forms of diabetes cannot be prevented, you can reduce your risk of developing prediabetes, type 2 diabetes, and gestational diabetes.
Key risk factors you can manage include:
Excess weight
A diet high in fats, sugars, and refined carbohydrates
Lack of exercise
Tobacco use
High blood pressure, low HDL cholesterol, high triglycerides, and heart disease
Poor sleep habits
Chronic stress
Although healthy habits can help reduce your risk, prediabetes and type 2 diabetes cannot always be prevented, and sometimes even occur in people who are naturally lean.
The causes of each type of diabetes may vary, but healthy habits such as diet and exercise are always an important part of diabetes management. Work with your healthcare team to identify specific lifestyle modifications that meet your individual needs.
Focus on Wholesome Food
There’s no one diabetes-friendly diet, and nutrition therapy advice may differ slightly for managing different types of diabetes. Nevertheless, health authorities have identified certain eating habits that are beneficial for everyone with diabetes.
Eat lots of nonstarchy vegetables.
Avoid added sugar and refined starches like flour or white rice.
Choose whole foods and ingredients rather than highly processed foods.
Most people with diabetes also need to be aware of how many carbohydrates they consume. Carbohydrates, even healthy ones found in fruit and whole grains, can cause rapid blood sugar increases. If you use insulin to manage your diabetes, you may be asked to count the carbohydrates of every meal and snack. Consult your healthcare provider or registered dietitian to find out how many carbohydrates you should be eating per day, as they’ll take any insulin or medication regimen into account.
Depending on other aspects of your health, you may be advised to limit your consumption of certain nutrients, including sodium or saturated fat. People with diabetic kidney disease (DKD), for example, may need to limit their sodium and protein consumption to avoid putting additional strain on the kidneys.
People with diabetes can work with dietitians for support in adopting a diet that fits their personal nutrition needs and cultural preferences. Popular diets today include the ketogenic, low-carbohydrate, Mediterranean, vegetarian, vegan, and DASH diets, all of which can be diabetes-friendly. The ideal diet for you may take into account several features of each diet without intense adherence to one protocol entirely.
Get Regular Exercise
Exercise works to lower blood glucose levels and improve insulin sensitivity by increasing the rate at which your cells take glucose from the bloodstream for use as fuel. Even light physical activity enhances both health and blood sugar management in people with diabetes.
The U.S. Department of Health and Human Services recommends getting 30 minutes of moderate to vigorous exercise at least five days per week, but be sure to consult your healthcare team before you begin exercising so they can advise you on the best way to proceed.
While regular physical activity is recommended for all people with diabetes, people with diabetes complications such as neuropathy may need to avoid certain kinds of exercise.
People who use insulin also need to be careful when exercising, as the temporary boost in insulin sensitivity can lead to hypoglycemia. It may take professional help and some trial and error to learn how to exercise safely with diabetes.
Other Lifestyle Factors
Changes in your daily lifestyle habits can significantly decrease your risk of developing prediabetes, gestational diabetes, and type 2 diabetes. Such lifestyle factors include:
Maintain a healthy weight. Preventing weight gain, losing weight, and maintaining a healthy weight is critical to prevent diabetes or achieve remission. Excess body fat significantly decreases insulin sensitivity.
Quit all forms of tobacco use. Nicotine both elevates blood glucose levels and causes insulin resistance. Quitting smoking can improve your circulation, reduce overall inflammation, and improve insulin sensitivity.
Manage your alcohol consumption. Excessive alcohol consumption can increase your risk of diabetes by reducing liver and pancreas function and thereby affecting your body’s blood glucose control. Reduce and manage your alcohol consumption to lower your risk of diabetes.
Get better sleep. A number of sleep problems, including insomnia and obstructive sleep apnea, are associated with insulin resistance, prediabetes, and diabetes.
Address your stress. Chronic stress can increase your risk of diabetes primarily through the overproduction of stress-related hormones like cortisol. Incorporate relaxation techniques such as meditation, deep breathing, and regular exercise to keep cortisol levels in check.
While some forms of diabetes are lifelong conditions, you can live a full life with any type of diabetes. The specific prognosis for life with diabetes varies depending on the type, your daily management of the condition, and your overall health.
Type 1 diabetes is a lifelong condition that requires daily attention, adjustments, and thoughtful lifestyle habits. The learning curve for successful type 1 diabetes management is significant, but people with type 1 diabetes can live very active, healthy lives while working to prevent or delay complications. The treatment of type 1 diabetes has improved massively in recent decades, with superior forms of insulin and management technology, allowing people with the condition to live longer lives.
Type 2 diabetes is usually a lifelong condition, but it can be managed with lifestyle changes and medication. With diligent self-care, people with type 2 diabetes can live very full, active, and healthy lives, and may not necessarily experience significant complications.
Gestational diabetes usually goes away after the baby is born and the women’s hormone levels normalize. But lifestyle factors can increase the risk of type 2 diabetes later in life for someone with a history of gestational diabetes.
Other forms of diabetes, like MODY, LADA, or diabetes from other causes, require specific care and support. As with other types of diabetes, working to manage healthy blood glucose levels is critical to improving long-term health.
Diabetes can lead to a variety of complications, which can range from uncomfortable to life-threatening.
Major long-term complications of diabetes include:
Diabetes can also create a number of short-term dangers:
Hypoglycemia (low blood glucose) is a risk for anyone taking insulin or non-insulin medications like sulfonylureas. Left untreated, hypoglycemia can lead to lightheadness, confusion, diabetic seizure, and even death.
Diabetic ketoacidosis (DKA) occurs when the body doesn’t have enough insulin to convert glucose into energy. It begins to break down fat for fuel, producing ketones at toxic levels. Left untreated, it can lead to seizures, coma, and death. DKA is most common in people with type 1 diabetes.
Hyperglycemic hyperosmolar nonketotic syndrome is an emergency caused by chronically high blood glucose levels. It’s most common in people with type 2 diabetes.
Diabetes affects people across the globe of all ages, ethnicities, and genders. Diabetes rates are rising in almost every country, and the disease has been widely described as a pandemic.
Prediabetes Prediabetes is extremely common. Researchers estimate that 9.1 percent of the global population (464 million people) have impaired glucose tolerance and 5.8 percent (298 million people) have impaired fasting glucose, two defining characteristics of prediabetes.
Type 2 Diabetes Approximately 537 million adults ages 20 to 79 worldwide have diabetes, the majority of whom have type 2 diabetes. This number is expected to rise to 643 million by 2030 and 783 million by 2045.
Type 1 Diabetes Although type 1 diabetes isn’t caused by lifestyle factors, incidences of type 1 diabetes are rising across the globe, with 9.4 million cases worldwide in 2024. Experts estimate there will be 16.4 million cases of type 1 diabetes by 2040.
Diabetes disproportionately affects certain racial and ethnic groups in the United States. Experts believe that the differences are largely due to social determinants of health, including access to affordable healthcare, insurance coverage, education, and healthy food.
People who belong to racial and ethnic minorities and those who are socioeconomically disadvantaged are more likely to develop type 2 diabetes and are more likely to experience significant complications, including kidney disease, amputation, and early death.
And people of color with type 1 diabetes are:
Less likely to be prescribed a continuous glucose monitor (CGM) or insulin pump
Less likely to be educated on new diabetes technology or medications
More likely to develop diabetes-related complications like neuropathy and retinopathy
More likely to experience frequent episodes of severe hypoglycemia that require hospitalization
More likely to experience DKA and require hospitalization
The root causes of these disparities are incredibly complex, and include economic, political, and social drivers. You may have to advocate for yourself to be sure that you receive the best care possible for your condition.
This organization aims to address the unique challenges faced by African Americans with any type of diabetes, including prevention, management, and education. It provides culturally conscious resources and support groups to help improve diabetes health and raise awareness about inequities in healthcare.
Diabetes Sisters
This nonprofit supports women with any type of diabetes, offering in-person and virtual meets, free educational resources, and educational webinars. The organization aims to empower women of all ages and diabetes types by discussing common challenges and providing real-life management support.
This nonprofit focuses primarily on supporting children, teens, and young adults with type 1 diabetes through in-person Wiffle tournaments, fundraising, sponsorships for Division I college athletes, and events across the country. By pairing sports and diabetes awareness, SLAMT1D empowers young people to challenge the stereotypes and stigma of type 1 diabetes, encouraging them to live active, fulfilling lives.
This organization strives to help young adults with type 1 and type 2 diabetes transition to adulthood by providing resources on health management, self-advocacy, and peer support. It offers programs designed specifically for college students and young adults with diabetes. The organization offers mentorship, education, and leadership opportunities.
There are several types of diabetes, each of which involves high blood glucose levels and is caused by some form of insulin dysfunction.
The symptoms of diabetes are generally the same regardless of the type because they are all caused by high blood sugar.
Diabetes is first diagnosed based on an individual’s blood glucose and A1C levels, potentially followed by additional testing to identify the type of diabetes.
While there isn’t a cure for diabetes, each type can be treated and managed with lifestyle changes, medication, and technology.
