This content originally appeared on Everyday Health. Republished with permission.

By Ginger Vieira

Medically Reviewed by Anna L. Goldman, MD

Type 1 and type 2 diabetes are both defined by high blood sugar levels. Consistently high blood sugar can lead to similar symptoms and complications. But type 1 diabetes and type 2 diabetes are different diseases in many other ways.

About 38 million Americans have diabetes. That’s more than 1 out of every 10 people. Type 1 diabetes accounts for about 5 to 10 percent of diagnoses.[1]

Here’s what you need to know to be health savvy in the era of a diabetes epidemic.

What Is Diabetes?

Diabetes is related to high blood sugar, but the type of diabetes determines why your blood sugar level is high.

What Type 1 Diabetes Does to the Body

People with type 1 diabetes do not produce enough of the hormone insulin. As a result, sugar builds up in the blood, instead of going to the cells where it’s needed for energy.[2] If left untreated, type 1 diabetes is fatal. Everyone needs insulin to live.

People with type 1 diabetes self-administer insulin every day for the rest of their lives. Using too much or too little insulin leads to both short- and long-term health issues. If type 1 diabetes is not managed carefully, it can lead to devastating consequences, such as diabetic coma, advanced kidney disease, blindness, or amputation.

What Type 2 Diabetes Does to the Body

Type 2 diabetes begins with insulin resistance, a state in which the body does not respond properly to the hormone insulin. Unlike people with type 1 diabetes, which is a disease of too little insulin, people with type 2 diabetes may initially have too much.[3]

Genetics and lifestyle habits both play a role in the body’s rising insulin needs. Eventually, the pancreas cannot produce enough insulin to keep up with the demand, and blood sugar levels go up. As the disease progresses, the pancreas may begin to lose its ability to create insulin, causing blood sugar levels to rise even higher. This blood sugar rise can result in the same damaging consequences as in type 1 diabetes, including cardiovascular disease, kidney failure, and early death.

Type 2 diabetes treatments — both medication and lifestyle changes — are mostly designed to correct the root cause of insulin resistance, so the insulin that your body does make works more effectively, bringing blood sugar levels down. If those treatments are ineffective, some patients will eventually need to self-administer insulin as a medicine.

Causes

What Causes Type 1 Diabetes?

“Type 1 diabetes is an autoimmune disease. The body’s immune system attacks the cells in the pancreas that make insulin,” says Andjela Drincic, MD, a professor in the division of diabetes, endocrinology, and metabolism at the University of Nebraska Medical Center in Omaha.

Insulin is a critical hormone that no mammal can live without. The sugar in your bloodstream cannot get into cells that need it for energy without insulin. Insulin is the key that unlocks a cell and allows sugar to enter.

The exact cause of type 1 diabetes is not known, but research suggests it’s a combination of the genes a person is born with and something in the environment that triggers the genes to become active. Though a family history of type 1 diabetes (or other autoimmune disorders) can increase the odds of developing the condition, its development seems essentially random.

What Causes Type 2 Diabetes?

“The cause of type 2 diabetes is multifactorial,” says Dr. Drincic. “People inherit genes that make them susceptible to type 2, but lifestyle factors, like obesity and inactivity, are also important. In type 2 diabetes, at least in the early stages, there is enough insulin, but the body becomes resistant to it.”

Risk factors for type 2 diabetes include a family history of the disease, poor diet, sedentary lifestyle, and obesity. Black, Latino, and Asian Americans as well as American Indians have a higher risk of type 2 diabetes than white Americans.[4]

Diabetes at Any Age: Type 1 or Type 2

Type 1 diabetes was once considered a childhood disease; it was even referred to as juvenile diabetes previously, but that is no longer the case today. Though the condition is common in youth, experts now recognize that more than half of new cases are diagnosed in people age 18 and older.[5]

The onset of type 1 diabetes may be more gradual in adults than in children. Some adults have a subtype of type 1 diabetes called LADA (latent autoimmune diabetes in adults), which progresses especially slowly. This means type 2 medications may seem effective for several years before insulin therapy is necessary.

Because of its slower onset, type 1 diabetes is often misdiagnosed as type 2 diabetes in adults. Approximately 38 percent of adults with type 1 are initially misdiagnosed with type 2.[6]

Type 2 diabetes is typically considered a disease of older adults, as the risk increases with age.[7] But that doesn’t mean that the condition cannot occur at earlier ages. Today, more children are being diagnosed with type 2 diabetes.[8] When it develops at an earlier age, type 2 diabetes is associated with more severe health outcomes.[9]

Symptoms

The Symptoms of Type 1 Diabetes

In most cases, the first symptoms of type 1 diabetes appear only after blood sugar levels have increased to a dangerously high level.

These symptoms include increased thirst, frequent urination, unexplained weight loss, and blurred vision. People may also experience rapid breathing, dry skin, fruity breath, and nausea.

In severe cases, undiagnosed type 1 diabetes can lead to a condition named diabetic ketoacidosis (DKA). DKA is life-threatening and should be treated in an emergency room with intravenous fluids and insulin. Many people with type 1 diabetes are diagnosed only after developing DKA. If you suspect you’re in DKA, get immediate treatment.

The Symptoms of Type 2 Diabetes

Type 2 diabetes tends to develop more slowly than type 1 diabetes and is less likely to result in immediate danger. For many, the symptoms of type 2 diabetes may not show up for many years, as their blood sugar level gradually rises to a more dangerous level. This means the disease can quietly damage nerves and blood vessels throughout the body for years.

Many people with type 2 diabetes are diagnosed at routine checkups, before they experience any symptoms. Others may notice one or more of the many subtle symptoms of chronically elevated blood sugar levels, including fatigue, dry mouth, inflamed gums, erectile dysfunction, recurring yeast infections, numbness or tingling in the extremities, and slow wound healing.

If left untreated, type 2 diabetes can lead to the same symptoms of acute high blood sugar as type 1 diabetes, such as frequent urination, thirst, hunger, blurred vision, and unexplained weight loss. In rare situations, people with type 2 diabetes can also develop DKA.[10]

Diagnosing Types 1 and 2 Diabetes

Both forms of diabetes, which are each defined by high blood sugar levels, are diagnosed using the same tests. Blood tests to diagnose type 1 and type 2 diabetes include fasting blood sugar, a hemoglobin A1C test, and a glucose tolerance test.[11] The A1C test measures the average blood sugar level over the past few months. The glucose tolerance test measures blood sugar after a sugary drink is given.

“The blood sugar testing we do to diagnose and manage type 1 diabetes is very similar to the testing we do for type 2 diabetes,” Drincic says. “We can do a blood test that looks for antibodies. That tells us if it is type 1 or 2.”

Determining a type 1 versus type 2 diabetes diagnosis can include the following:

Testing for Autoantibodies Autoantibodies develop when the immune system attacks the cells in the pancreas that produce insulin. The presence of autoantibodies indicates type 1 diabetes. Your healthcare provider can arrange a blood draw for an autoantibody screening, but there are also multiple resources to get screened at home. A nonprofit named The Diabetes Link curates a list of options for at-home screening.
C-Peptide Levels C-peptide indicates how much insulin your pancreas is producing. People with type 1 diabetes have very low c-peptide levels, while people with type 2 tend to have very high c-peptide levels. C-peptide levels are tested through a traditional intravenous blood draw.[12]

Your doctor may suspect type 2 diabetes based on risk factors such as obesity and family history, or symptoms such as dark, velvety skin (acanthosis nigricans). Considering the rate of misdiagnosis, it may be prudent to rule out type 1 diabetes regardless of your weight or age by testing your c-peptide level or checking for autoantibodies.

The Treatment of Type 1 and Type 2 Diabetes

Treating and managing type 1 or type 2 diabetes can involve multiple lifestyle habit changes, medications, and technology, and there is a great deal of overlap between the two conditions.

Diet, Exercise and Lifestyle Changes for Type 1 and Type 2 Diabetes

Regardless of the diabetes type, lifestyle habits will have a significant impact on your health and the management of your condition. Diet, exercise, and other lifestyle decisions can improve your body’s sensitivity to insulin or reduce your need for insulin, both of which will make it easier to manage your blood sugar (and your weight).

Diabetes doesn’t mean you need to eat perfectly, but making healthy choices may be the most important single thing you can do to keep your blood sugar in a healthy range.

Some common recommendations include:

Eat more whole foods and vegetables.[13]
Eat fewer highly processed foods.[14]
Watch your carbohydrate intake.
Look for lean proteins or plant-based proteins.
Get regular exercise.
Limit alcohol consumption.
Quit smoking.[15]
Prioritize healthy sleep.

Insulin for Type 1 Diabetes

The treatment of both type 1 and type 2 diabetes relies on the use of drugs, which help lower blood glucose levels.

Insulin is perhaps the most important drug in the treatment of diabetes. “The big difference is that everybody with type 1 diabetes needs to take insulin,” says Shannon Knapp, RN, CDCES, a diabetes educator at the Cleveland Clinic in Ohio.

People with type 1 diabetes have an absolute need for the hormone insulin and will eventually die without it. Most people with the condition need to take insulin multiple times every day, often deciding themselves how much insulin to take and when. Insulin lowers blood sugar levels powerfully, but it can trigger the dangerous side effect of hypoglycemia. There is a substantial learning curve to the use of this drug.

Today’s insulin options are vast, and so are the technologies you can use to dose and administer insulin. Insulin comes in multiple forms. It can be administered by injection or infused continuously with an insulin pump. Inhaled insulin is also available. Some newer insulin pumps offer a hybrid closed-loop system that communicates directly with a continuous glucose monitor, making automatic adjustments to insulin doses.

Drugs for Type 2 Diabetes

There is no one-size-fits-all approach to type 2 diabetes medications. Though most people with type 2 diabetes are offered metformin as a first-line treatment, your healthcare provider will consider your entire health profile in recommending additional drug therapies.

Other options include:

Glucagon-like peptide 1 (GLP-1) and dual GLP-1/gastric inhibitory peptide receptor agonists, which have become famous for their extraordinary ability to induce weight loss
Dipeptidyl peptidase 4 inhibitors
Sodium-glucose cotransporter 2 inhibitors (SGLT2s)
Sulfonylureas
Thiazolidinediones
Alpha-glucosidase inhibitors

These medications work in different ways to improve blood sugar levels or insulin resistance. The newest drug classes, GLP-1 receptor agonists and SGLT2 inhibitors, also offer long-term protection to kidney and heart health.

Everyone reacts differently to these medications, which means you should tell your doctor right away if you’re experiencing severe side effects or if you aren’t seeing improvements in your blood sugar levels.

While the above medications are approved by the U.S. Food and Drug Administration only to treat type 2 diabetes, some are also prescribed off-label to people with type 1 diabetes. (Some type 2 drugs are inappropriate for people with type 1 diabetes, such as SGLT2 inhibitors, which carry a risk of diabetic ketoacidosis.)

Finally, insulin is an option for people with type 2 diabetes who have been unable to keep their blood sugar at a safe level with the other drugs and lifestyle changes. “Over time, if the pancreas stops making insulin, some people with type 2 will also need insulin,” says Knapp.

Blood Sugar Monitoring

Monitoring your blood sugar levels is critical in both type 1 and type 2 diabetes. The more aware you are of your blood glucose, the easier it is to understand what changes in diet, exercise, lifestyle, or medication will benefit your metabolic health.

When they are first diagnosed, most people with diabetes are given a prescription for a blood glucose meter. These devices measure blood sugar levels from a drop of blood; the measurements are sometimes called finger sticks because the devices use a sharp lancet to draw blood from the fingertips.

A newer technology, the continuous glucose monitor (CGM) can measure blood sugar levels around the clock. This device adheres to the upper arm, torso, or elsewhere on the body. A small hairlike cannula penetrates below the skin. The CGM automatically updates a smartphone app or dedicated CGM transmitter with new measurements. It can also raise an alarm if blood sugar levels are trending dangerously high or low.

All people with diabetes who use insulin are encouraged to check blood sugar levels multiple times per day and can benefit especially from the use of CGMs. Insurers may be less eager to cover the cost of a CGM for people with type 2 diabetes who do not require insulin with every meal, but the device can still help lower A1C levels, and it’s getting easier to buy a CGM over the counter.[16]

What Are the Complications of Diabetes?

The complications of diabetes — long-term health conditions that are partially or entirely caused by diabetes — are largely the result of persistently high blood sugar levels. Excess sugar in your bloodstream wreaks havoc on blood vessels and nerves throughout your entire body.

“Whether it’s type 1 or type 2,” Drinsic says, “the big picture for diabetes is all about preventing complications,” which are mostly related to nerve and blood vessel damage.

Diabetes affects almost every part of the body. A partial list of complications includes:

Retinopathy (eye disease, which can lead to vision loss)
Nephropathy (kidney disease)
Neuropathy (numbness, tingling, or pain in the hands, feet, and legs)
Heart disease, including stroke and heart attack

These conditions can progress to severe states, especially if diabetes is left unmanaged for a long time. Some of the worst outcomes of diabetes include amputation, blindness, and early death. People with type 1 and type 2 diabetes are both at risk of these dire consequences.

To minimize or prevent diabetes complications, the American Diabetes Association sets a goal for most adults of an A1C below 7.0 percent.[17]

Prevention

Can Type 1 Diabetes be Prevented?

“As of now, there is no way to prevent type 1 diabetes,” Drincic says. A significant number of clinical trials are ongoing, with the goal of preventing or delaying the condition, and one drug is approved to delay the onset of full-blown type 1 diabetes, according to Everyday Health’s network site Diabetes Daily.

Can Type 2 Diabetes be Prevented?

It takes effort, but type 2 diabetes can be prevented before it develops.

“The best cure for type 2 diabetes is prevention, and research on that is very exciting,” Drincic says. “Losing a moderate amount of weight and exercising regularly can reduce or delay type 2 diabetes significantly.”

A landmark Finnish study followed 522 middle-aged adults who were overweight and had risk factors for type 2 diabetes. A weight-loss diet and 30 minutes of daily exercise lowered their risk of developing type 2 diabetes by 58 percent compared with those who didn’t follow the diet or exercise.[18]

Diabetes Cures and Remission

There is no cure for type 1 diabetes, but the research into a potential cure appears to be extremely promising. Some people with type 1 diabetes have been cured of the need for daily insulin injections with transplants of the pancreas or pancreatic cells, but those solutions, which rely on organ donors and require significant regimens of immunosuppressive drugs, are impractical or inaccessible for most people with the disease.[19] It is possible that in the coming decades, there will be a workable type 1 diabetes cure.

Type 2 diabetes cannot be cured exactly, but it is possible to put the disease into remission.[20] Some people — especially those who have been recently diagnosed with type 2 diabetes — can achieve normal blood sugar levels exclusively through changes in diet, exercise, and weight loss.[21]

Others will always need medicine to help keep their blood sugar levels under control, no matter how carefully they follow diet and exercise recommendations. Type 2 diabetes is considered a progressive disease. Since your natural ability to produce insulin gradually declines or insulin resistance worsens, you may eventually need stronger medications, such as GLP-1s or insulin, to manage your condition.[22]

The Takeaway

Managing type 1 or type 2 diabetes is a complicated and challenging experience that requires daily attention, constant learning, and tremendous support from your healthcare team. But thanks to advancements in diabetes medications and technology, people with diabetes can live long, fulfilling lives.

Additional reporting by Chris Iliades, MD.

Resources We Trust

Mayo Clinic: Latent Autoimmune Diabetes in Adults (LADA): What Is It?
Diabetes UK: I Am the Director of My Diabetes After Agony of Misdiagnosis
Children’s Hospital of Philadelphia: Atypical Diabetes
Cleveland Clinic: Brittle Diabetes
UC Health: Is There a Gray Area Between Type 1 and Type 2 Diabetes?

Editorial Sources and Fact-Checking