Home Medical Topics Diabetes : Type, Risk factors, Causes & Treatments

Diabetes : Type, Risk factors, Causes & Treatments



When your body is unable to absorb sugar (glucose) into its cells and use it for energy, you develop diabetes. As a result, more sugar builds up in your bloodstream.

Diabetes management mistakes can have serious consequences, causing damage to your heart, kidneys, eyes, and nerves, among other organs and tissues.

Why is my blood glucose level high? How does this happen?

Breaking down food into its various nutrient sources is an important part of digestion. Your body converts carbohydrates like bread, rice, and pasta into sugar (glucose) when you eat them. When glucose enters your bloodstream, it needs assistance—a “key”—to get inside your body’s cells, where it will be used. Cells are what make up your body’s tissues and organs. Insulin is the help or “key” here.

Your pancreas, an organ behind your stomach, is responsible for the production of insulin, a hormone. Insulin is pumped into your bloodstream by your pancreas. Insulin is the “key” that opens the “door” in the cell wall, allowing glucose to enter your body’s cells. The “fuel,” or energy, that tissues and organs require to function properly is provided by glucose.

Those with diabetes:

  • Your pancreas doesn’t make any insulin or enough insulin.


  • Your pancreas makes insulin but your body’s cells don’t respond to it and can’t use it as it normally should.

If glucose can’t get into your body’s cells, it stays in your bloodstream and your blood glucose level rises.

Type of diabetes?

he types of diabetes are:

  • Type 1 diabetes: This type is an autoimmune disease, meaning your body attacks itself. In this case, the insulin-producing cells in your pancreas are destroyed. Up to 10% of people who have diabetes have Type 1. It’s usually diagnosed in children and young adults (but can develop at any age). It was once better known as “juvenile” diabetes. People with Type 1 diabetes need to take insulin every day. This is why it is also called insulin-dependent diabetes.
  • Type 2 diabetes: With this type, your body either doesn’t make enough insulin or your body’s cells don’t respond normally to the insulin. This is the most common type of diabetes. Up to 95% of people with diabetes have Type 2. It usually occurs in middle-aged and older people. Other common names for Type 2 include adult-onset diabetes and insulin-resistant diabetes. Your parents or grandparents may have called it “having a touch of sugar.”
  • Prediabetes: This type is the stage before Type 2 diabetes. Your blood glucose levels are higher than normal but not high enough to be officially diagnosed with Type 2 diabetes.
  • Gestational diabetes: This type develops in some women during their pregnancy. Gestational diabetes usually goes away after pregnancy. However, if you have gestational diabetes you’re at higher risk of developing Type 2 diabetes later on in life.

Less common types of diabetes include:

  • Monogenic diabetes syndromes: These are rare inherited forms of diabetes accounting for up to 4% of all cases. Examples are neonatal diabetes and maturity-onset diabetes of the young.
  • Cystic fibrosis-related diabetes: This is a form of diabetes specific to people with this disease.
  • Drug or chemical-induced diabetes: Examples of this type happen after organ transplant, following HIV/AIDS treatment or are associated with glucocorticoid steroid use.

Risk factors

Factors that increase your risk differ depending on the type of diabetes you ultimately develop.

Risk factors for Type 1 diabetes include:

  • Having a family history (parent or sibling) of Type 1 diabetes.
  • Injury to the pancreas (such as by infection, tumor, surgery or accident).
  • Presence of autoantibodies (antibodies that mistakenly attack your own body’s tissues or organs).
  • Physical stress (such as surgery or illness).
  • Exposure to illnesses caused by viruses.

Risk factors for prediabetes and Type 2 diabetes include:

  • Family history (parent or sibling) of prediabetes or Type 2 diabetes.
  • Being Black, Hispanic, Native American, Asian-American race or Pacific Islander.
  • Having overweight/obesity.
  • Having high blood pressure.
  • Having low HDL cholesterol (the “good” cholesterol) and high triglyceride level.
  • Being physically inactive.
  • Being age 45 or older.
  • Having gestational diabetes or giving birth to a baby weighing more than 9 pounds.
  • Having polycystic ovary syndrome.
  • Having a history of heart disease or stroke.
  • Being a smoker.

Risk factors for gestational diabetes include:

  • Family history (parent or sibling) of prediabetes or Type 2 diabetes.
  • Being African-American, Hispanic, Native American or Asian-American.
  • Having overweight/obesity before your pregnancy.
  • Being over 25 years of age.


The cause of diabetes, regardless of the type, is having too much glucose circulating in your bloodstream. However, the reason why your blood glucose levels are high differs depending on the type of diabetes.

  • Causes of Type 1 diabetes: This is an immune system disease. Your body attacks and destroys insulin-producing cells in your pancreas. Without insulin to allow glucose to enter your cells, glucose builds up in your bloodstream. Genes may also play a role in some patients. Also, a virus may trigger the immune system attack.
  • Cause of Type 2 diabetes and prediabetes: Your body’s cells don’t allow insulin to work as it should to let glucose into its cells. Your body’s cells have become resistant to insulin. Your pancreas can’t keep up and make enough insulin to overcome this resistance. Glucose levels rise in your bloodstream.
  • Gestational diabetes: Hormones produced by the placenta during your pregnancy make your body’s cells more resistant to insulin. Your pancreas can’t make enough insulin to overcome this resistance. Too much glucose remains in your bloodstream.


Symptoms of diabetes include:

  • Increased thirst.
  • Weak, tired feeling.
  • Blurred vision.
  • Numbness or tingling in the hands or feet.
  • Slow-healing sores or cuts.
  • Unplanned weight loss.
  • Frequent urination.
  • Frequent unexplained infections.
  • Dry mouth.

Type 1 diabetes symptoms: Symptoms can develop quickly – over a few weeks or months. Symptoms begin when you’re young – as a child, teen or young adult. Additional symptoms include nausea, vomiting or stomach pains and yeast infections or urinary tract infections.

Type 2 diabetes and prediabetes symptoms: You may not have any symptoms at all or may not notice them since they develop slowly over several years. Symptoms usually begin to develop when you’re an adult, but prediabetes and Type 2 diabetes is on the rise in all age groups.

Gestational diabetes: You typically will not notice symptoms. Your obstetrician will test you for gestational diabetes between 24 and 28 weeks of your pregnancy.


If your blood glucose level remains high over a long period of time, your body’s tissues and organs can be seriously damaged. Some complications can be life-threatening over time.

Complications include:


Diabetes is diagnosed and managed by checking your glucose level in a blood test. There are three tests that can measure your blood glucose level: fasting glucose test, random glucose test and A1c test.

  • Fasting plasma glucose test: This test is best done in the morning after an eight hour fast (nothing to eat or drink except sips of water).
  • Random plasma glucose test: This test can be done any time without the need to fast.
  • A1c test: This test, also called HbA1C or glycated hemoglobin test, provides your average blood glucose level over the past two to three months. This test measures the amount of glucose attached to hemoglobin, the protein in your red blood cells that carries oxygen. You don’t need to fast before this test.
  • Oral glucose tolerance test: In this test, blood glucose level is first measured after an overnight fast. Then you drink a sugary drink. Your blood glucose level is then checked at hours one, two and three.
Type of testNormal
glucose test
Less than 100​100-125126 or higher
Random (anytime)
glucose test
Less than 140​140-199200 or higher
A1c testLess than 5.7%​5.7 – 6.4%6.5% or higher
Oral glucose
tolerance test
Less than 140140-199200 or higher

Tests for gestational diabetes: If you are pregnant, you will need to have two blood glucose tests. In a glucose challenge test, you drink a sugary beverage and have your glucose level checked after an hour. Prior to this test, you do not need to sprint. An oral glucose tolerance test will be performed (as previously mentioned) in the event that this test reveals a glucose level that is higher than normal (over 140 ml/dL).

Diabetes mellitus: Blood and urine samples will be taken and tested if your doctor suspects Type 1 diabetes. Autoantibodies, which are a sign that your body is attacking itself, are examined in the blood. Ketones, which are a sign that your body is burning fat for energy, are checked for in the urine. Diabetes type 1 is indicated by these signs.

Who should be tested for diabetes?

If you have symptoms or risk factors for diabetes, you should get tested. The earlier diabetes is found, the earlier management can begin and complications can be lessened or prevented. If a blood test determines you have prediabetes, you and your healthcare professional can work together to make lifestyle changes (e.g. weight loss, exercise, healthy diet) to prevent or delay developing Type 2 diabetes.

Additional specific testing advice based on risk factors:

  • Testing for Type 1 diabetes: Test in children and young adults who have a family history of diabetes. Less commonly, older adults may also develop Type 1 diabetes. Therefore, testing in adults who come to the hospital and are found to be in diabetes-related ketoacidosis is important. Ketoacidosis a dangerous complication that can occur in people with Type 1 diabetes.
  • Testing for type 2 diabetes: Test adults age 45 or older, those between 19 and 44 who have overweight/obesity and have one or more risk factors, women who have had gestational diabetes, children between 10 and 18 who overweight/obesity and have at least two risk factors for type 2 diabetes.
  • Gestational diabetes: Test all pregnant women who have had a diagnosis of diabetes. Test all pregnant women between weeks 24 and 28 of their pregnancy. If you have other risk factors for gestational diabetes, your obstetrician may test you earlier.


Treatments for diabetes depend on your type of diabetes, how well managed your blood glucose level is and your other existing health conditions.

  • Type 1 diabetes: If you have this type, you must take insulin every day. Your pancreas no longer makes insulin.
  • Type 2 diabetes: If you have this type, your treatments can include medications (both for diabetes and for conditions that are risk factors for diabetes), insulin and lifestyle changes such as losing weight, making healthy food choices and being more physically active.
  • Prediabetes: If you have prediabetes, the goal is to keep you from progressing to diabetes. Treatments are focused on treatable risk factors, such as losing weight by eating a healthy diet (like the Mediterranean diet) and exercising (at least five days a week for 30 minutes). Many of the strategies used to prevent diabetes are the same as those recommended to treat diabetes (see prevention section of this article).
  • Gestational diabetes: If you have this type and your glucose level is not too high, your initial treatment might be modifying your diet and getting regular exercise. If the target goal is still not met or your glucose level is very high, your healthcare team may start medication or insulin.

Oral medications and insulin work in one of these ways to treat your diabetes:

  • Stimulates your pancreas to make and release more insulin.
  • Slows down the release of glucose from your liver (extra glucose is stored in your liver).
  • Blocks the breakdown of carbohydrates in your stomach or intestines so that your tissues are more sensitive to (better react to) insulin.
  • Helps rid your body of glucose through increased urination.

Diabetes medication drug classes include:

  • Sulfonylureas: These drugs lower blood glucose by causing the pancreas to release more insulin. Examples include glimepiride (Amaryl®), glipizide (Glucotrol®) and glyburide (Micronase®, DiaBeta®).
  • Glinides (also called meglitinides): These drugs lower blood glucose by getting the pancreas to release more insulin. Examples include repaglinide (Prandin®) and nateglinide (Starlix®).
  • Biguanides: These drugs reduce how much glucose the liver produces. It also improves how insulin works in the body, and slows down the conversion of carbohydrates into sugar. Metformin (Glucophage®) is the example.
  • Alpha-glucosidase inhibitors: These drugs lower blood glucose by delaying the breakdown of carbohydrates and reducing glucose absorption in the small intestine. An example is acarbose (Precose®).
  • Thiazolidinediones: These drugs improve the way insulin works in the body by allowing more glucose to enter into muscles, fat and the liver. Examples include pioglitazone (Actos®) and rosiglitazone (Avandia®).
  • GLP-1 analogs (also called incretin mimetics or glucagon-like peptide-1 receptor agonists): These drugs increase the release of insulin, reduce glucose release from the liver after meals and delay food emptying from the stomach. Examples include exenatide (Byetta®), liraglutide (Victoza®), albiglutide (Tanzeum®), semaglutide (Rybelsus®) and dulaglutide (Trulicity®).
  • DPP-4 inhibitors (also called dipeptidyl peptidase-4 inhibitors): These drugs help your pancreas release more insulin after meals. They also lower the amount of glucose released by the liver. Examples include alogliptin (Nesina®), sitagliptin (Januvia®), saxagliptin (Onglyza®) and linagliptin (Tradjenta®).
  • SGLT2 inhibitors (also called sodium-glucose cotransporter 2 inhibitors): These drugs work on your kidneys to remove glucose in your body through your urine. Examples include canagliflozin (Invokana®), dapagliflozin (Farxiga®) and empagliflozin (Jardiance®).
  • Bile acid sequestrants: These drugs lower cholesterol and blood sugar levels. Examples include colestipol (Colestid®), cholestyramine (Questran®) and colesevelam (Welchol®).
  • Dopamine agonist: This medication lowers the amount of glucose released by the liver. An example is bromocriptine (Cyclocet®).
What insulin medications are approved to treat diabetes?

There are many types of insulins for diabetes. If you need insulin, you healthcare team will discuss the different types and if they are to be combined with oral medications. To follow is a brief review of insulin types.

  • Rapid-acting insulins: These insulins are taken 15 minutes before meals, they peak (when it best lowers blood glucose) at one hour and work for another two to four hours. Examples include insulin glulisine (Apidra®), insulin lispro (Humalog®) and insulin aspart (NovoLog®).
  • Short-acting insulins: These insulins take about 30 minutes to reach your bloodstream, reach their peak effects in two to three hours and last for three to six hours. An example is insulin regular (Humulin R®).
  • Intermediate-acting insulins: These insulins reach your bloodstream in two to four hours, peak in four to 12 hours and work for up to 18 hours. An example in NPH.
  • Long-acting insulins: These insulins work to keep your blood sugar stable all day. Usually, these insulins last for about 18 hours. Examples include insulin glargine (Basaglar®, Lantus®, Toujeo®), insulin detemir (Levemir®) and insulin degludec (Tresiba®).

There are insulins that are a combination of different insulins. There are also insulins that are combined with a GLP-1 receptor agonist medication (e.g. Xultophy®, Soliqua®).

How many different ways are there to take insulin?

Insulin is available in several different formats. You and your healthcare provider will decide which delivery method is right for you based on your preference, lifestyle, insulin needs and insurance plan. Here’s a quick review of available types.

  • Needle and syringe: With this method, you’ll insert a needle into a vial of insulin, pull back the syringe and fill the needle with the proper dose of insulin. You’ll inject the insulin into your belly or thigh, buttocks or upper arm – rotating the injection spots. You may need to give yourself one or more shots a day to maintain your target blood glucose level.
  • Insulin pen: This device looks like a pen with a cap. They come prefilled with insulin or with insulin cartridges that are inserted and replaced after use.
  • Insulin pump: Insulin pumps are small, computerized devices, about the size of a small cell phone that you wear on your belt, in your pocket, or under your clothes. They deliver rapid-acting insulin 24 hours a day through a small flexible tube called a cannula. The cannula is inserted under the skin using a needle. The needle is then removed leaving only the flexible tube under the skin. You replaces the cannula every two to three days. Another type of insulin pump is attached directly to your skin and does not use tubes.
  • Artificial pancreas (also called a closed loop insulin delivery system): This system uses an insulin pump linked to a continuous glucose monitor. The monitor checks your blood glucose levels every five minutes and then the pump delivers the needed dose of insulin.
  • Insulin inhaler: Inhalers allow you to breath in powdered inhaler through an inhaler device that you insert into your mouth. The insulin is inhaled into your lungs, then absorbed into your bloodstream. Inhalers are only approved for use by adults with Type 1 or Type 2 diabetes.
  • Insulin injection port: This delivery method involves the placement of a short tube into tissue beneath your skin. The port is held in place with an adhesive patch. You use a needle and syringe or insulin pen and inject the insulin through this port. The port is changed every few days. The port provides a single site for injection instead of having to rotate injection sites.
  • Jet injector: This is a needleless delivery method that uses high pressure to send a fine spray of insulin through your skin.
Are there other treatment options for diabetes?

Yes. There are two types of transplantations that might be an option for a select number of patients who have Type 1 diabetes. A pancreas transplant is possible. However, getting an organ transplant requires taking immune-suppressing drugs for the rest of your life and dealing with the side effects of these drugs. However, if the transplant is successful, you’ll likely be able to stop taking insulin.

Another type of transplant is a pancreatic islet transplant. In this transplant, clusters of islet cells (the cells that make insulin) are transplanted from an organ donor into your pancreas to replace those that have been destroyed.

Another treatment under research for Type 1 diabetes is immunotherapy. Since Type 1 is an immune system disease, immunotherapy holds promise as a way to use medication to turn off the parts of the immune system that cause Type 1 disease.

Bariatric surgery is another treatment option that’s an indirect treatment for diabetes. Bariatric surgery is an option if you have Type 2 diabetes, have obesity (body mass index over 35) and considered a good candidate for this type of surgery. Much improved blood glucose levels are seen in people who have lost a significant amount of weight.

Of course other medications are prescribed to treat any existing health problems that contribute to increasing your risk of developing diabetes. These conditions include high blood pressure, high cholesterol and other heart-related diseases.


Although diabetes risk factors like family history and race can’t be changed, there are other risk factors that you can manage, to an extent. Adopting some of the healthy lifestyle habits listed below can improve these modifiable risk factors and help to decrease your chances of getting diabetes:

  • Eat a healthy diet, such as the Mediterranean or Dash diet. Keep a food diary and calorie count of everything you eat. Cutting 250 calories per day can help you lose ½ pound per week.
  • Get physically active. Aim for 30 minutes a day at least five days a week. Start slow and work up to this amount or break up these minutes into more doable 10-minute segments. Walking is great exercise.
  • Work to achieve a weight that’s healthy for you. Don’t lose weight if you are pregnant, but check with your obstetrician about healthy weight gain during your pregnancy.
  • Lower your stress. Learn relaxation techniques, deep breathing exercises, mindful meditation, yoga and other helpful strategies.
  • Limit alcohol intake. Men should drink no more than two beverages containing alcohol a day; women should drink no more than one.
  • Get an adequate amount of sleep (typically 7 to 9 hours).
  • Quit smoking.
  • Take medications as directed by your healthcare provider to manage existing risk factors for heart disease (like high blood pressure, cholesterol) or to reduce the risk of developing Type 2 diabetes.
  • If you think you have symptoms of prediabetes, see your provider.

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