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What Is Diabetes?
Diabetes is a disease that causes high blood sugar. It affects about 11% of the U.S. population.
Most forms of diabetes are long-term health issues that prevent your body from using sugar (glucose) for energy. Blood sugar fuels the cells in your body so they work correctly.
Your body digests the carbohydrates you eat and releases them into the blood as glucose. When glucose builds up in your blood, it signals your pancreas to release a hormone called insulin.
Insulin's job is to move the sugar from your blood into your cells for them to use as fuel.
Diabetes occurs when your body can't make enough insulin, or your body can't use insulin properly.
As a result, too much glucose stays in your bloodstream.
Over time, high blood sugar can lead to other health problems.
What are the types of diabetes?
There are three main types of diabetes:
- Type 1 is when your body stops making insulin. As a result, you must take insulin shots daily or through a pump to stay alive. Type 1 diabetes often appears in kids or teens but can happen at any age.
- Type 2 is the most common type of diabetes. It mostly affects adults who are overweight or have a family history. Typically the body still makes insulin, but your body doesn't use it right, causing high blood sugar.
- Gestational diabetes only happens to pregnant people. It's caused by hormones in the placenta that make insulin not work right. It often starts between 20 and 24 weeks gestation and goes away after birth.
What causes diabetes?
Each type of diabetes has different causes.
Type 1 diabetes is an autoimmune disease. The immune system attacks and destroys the insulin-producing cells in the pancreas.
Scientists aren't sure how type 1 diabetes starts or how to prevent it. It might happen because of your genes or certain viruses that trigger the immune system.
Type 2 diabetes often develops because of genetics, lifestyle factors (like not being active enough), and being overweight. It often starts as insulin resistance, which means insulin isn't working well.
As blood sugar levels increase due to the resistance, the pancreas tries to make more insulin. Eventually, it can't keep up, and blood sugar remains high. Over time, your insulin-making cells may get damaged from working too hard.
Gestational diabetes occurs during pregnancy in women who do not have type 1 or type 2 diabetes.
Hormones made by the placenta turn up your body's insulin resistance to ensure the baby gets enough sugar. Usually, the pancreas makes more insulin to compensate.
In some people, the pancreas doesn't make enough insulin, causing higher-than-normal blood sugars. Once the baby and placenta are out, hormones and blood sugar levels return to normal.
What are diabetes risk factors and complications?
Certain factors outside your control — like your genes, age, or ethnicity — can increase your risk of diabetes.
But there are other risk factors you can control to prevent or delay type 2 diabetes.
If you get diabetes, doing all you can to reduce the risk of long-term health problems is essential. Diabetes complications are more likely if you have chronically high blood sugar.
Diabetes risk factors
These factors increase your risk of diabetes:
- Family history. Having a parent or sibling with diabetes increases your risk.
- Age. The risk of type 2 diabetes and gestational diabetes increases after 40. Type 1 diabetes most commonly affects kids, teens, or young adults.
- Race or ethnicity. Type 2 diabetes is more common in people who are African American, Hispanic/Latino, American Indian, Asian American, or Pacific Islander.
- Certain health conditions. Polycystic ovary syndrome, non-alcoholic fatty liver disease, and gestational diabetes increase your risk of type 2 diabetes.
- Belly fat. Carrying excess weight in your belly causes insulin resistance, a sign of prediabetes.
- A sedentary lifestyle. Sitting too much contributes to weight gain. Routine exercise makes it easier to maintain a healthy weight and helps your insulin to work better.
- Certain medicines. Glucocorticoids (Prednisone or Cortisone), some blood pressure medications (diuretics), and anti-rejection drugs for an organ transplant can increase your risk.
- Damage to your pancreas. Health issues that damage the pancreas, like pancreatitis and pancreatic cancer, can increase diabetes risk. Having your pancreas removed gives you type 1 diabetes.
The best way to reduce your risk of diabetes is to live a healthy lifestyle and maintain a healthy weight.
Always follow your doctor's advice about health issues that can increase your diabetes risk.
Complications of diabetes
If left untreated, diabetes can lead to:
- Heart disease or stroke. High blood sugar damages blood vessels in your heart and brain. High blood pressure or cholesterol and being overweight increase your heart attack or stroke risk.
- Nerve damage (diabetic neuropathy). Diabetes often damages nerves in your feet, limbs, or organs, like your heart or stomach.
- Kidney disease. Diabetes is a leading cause of kidney disease. It damages blood vessels in your kidneys, preventing them from filtering toxins from your blood. Having high blood pressure further increases your risk of kidney damage.
- Vision problems. High blood sugar affects nerves and blood vessels in your eyes, causing low vision or blindness.
- Sexual or urinary tract problems. Diabetes can damage nerves and blood vessels. This can cause problems like erectile dysfunction, painful sex in women, bladder leaks, or trouble emptying your bladder.
- Dementia. Chronically high blood sugar can also harm your brain cells and blood vessels in the brain. That may increase your risk of memory problems, dementia, or Alzheimer's disease.
- Delivery issues. Uncontrolled gestational diabetes can cause your baby to grow too large. This may cause complications during delivery requiring a c-section and increasing the stillbirth risk.
Your care team will help you check and manage your blood sugar to reduce your risk of these complications.
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Diabetes Symptoms and Diagnosis
What are the signs and symptoms of diabetes?
Diabetes symptoms can vary depending on how high your blood sugar is.
Type 1 diabetes causes more severe symptoms that come on quickly.
Type 2 or gestational diabetes may cause mild symptoms that are easy to miss. Or you may not have any major symptoms until complications arise.
The most common symptoms and early signs of Type 1 diabetes include:
- Blurred vision.
- Feeling unusually tired.
- Frequent urination.
- Increased thirst or hunger.
- Numbness or tingling in your hands or feet.
- Sores or wounds that do not heal.
- Unexplained fatigue.
- Unexplained weight loss.
Call your doctor if you or your child has these diabetes symptoms, especially if they are severe or happen suddenly. They can check your blood sugar and test for diabetes.
Sometimes, one of the first signs of Type 1 diabetes is a life-threatening condition called diabetic ketoacidosis (DKA). It happens when there is little or no insulin available.
In addition to the above symptoms, DKA causes:
- Breath that smells fruity.
- Confusion.
- Trouble breathing.
- Flushed skin.
- Nausea or vomiting.
- Stomach pain.
DKA is very serious and possibly deadly.
If you or your child has any of these symptoms, call 911 and get to the hospital quickly.
How do you diagnose diabetes?
Doctors diagnose type 1 or 2 diabetes by measuring the amount of sugar in your blood. They'll do a quick finger prick test or draw blood to check your glucose levels.
Your blood sugar is lowest when fasting (nothing to eat for at least 8 hours). It increases after a meal.
You may have diabetes if:
- Your blood sugar is 126 mg/dL or higher when you haven't eaten in at least 8 hours (fasting).
- Your blood sugar is 200 mg/dL or higher after a meal or at any time of the day.
They'll likely also test your hemoglobin A1C levels using a blood draw. A1C indicates your average blood sugar level over the last 2 to 3 months. A1C levels should be six or lower.
All pregnant women have a blood test to screen for gestational diabetes between 24 and 28 weeks of pregnancy. The lab will ask you to drink a very sweet glucose beverage and draw your blood an hour afterward.
If that reading exceeds 140 mg/dL, you may need a 3-hour glucose tolerance test. This test is similar, but the drink has more sugar. The tech tests your blood when fasting and then each hour for three hours.
Gestational diabetes blood sugar level cut-offs are lower because the high glucose is dangerous to the baby.
You may have gestational diabetes if the 3-hour test comes back with two or more readings above these bounds:
- Fasting blood glucose above 95 mg/dL.
- One-hour blood glucose level reading over 180 mg/dL.
- Two-hour blood glucose level reading over 155 mg/dL.
- Three-hour blood glucose level reading above 140 mg/dL.
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How Do You Treat Diabetes?
Doctors treat diabetes in various ways based on:
- The type of diabetes.
- How severe it is.
- Other health risk factors you may have.
Diet and lifestyle
A healthy diet and lifestyle can help improve your blood sugar and make it easier to manage diabetes.
UPMC has a team of registered dietitians, exercise therapists, and behavioral health experts to help you:
- Check your blood sugar as suggested.
- Cut back on desserts, sweetened beverages, and foods with added sugar.
- Eat more high-fiber fruits, vegetables, beans, nuts, seeds, whole grains, and fewer foods with added sugar.
- Get at least 30 minutes of aerobic exercise most days of the week. Add in two or more days of strength training.
- Quit smoking if you smoke cigarettes.
Medicines to treat diabetes
Many people with type 2 or gestational diabetes can manage their blood sugar with diet and lifestyle changes.
If you need more help, your doctor may suggest these medicines:
- Insulin. Lifelong insulin is essential for type 1 diabetes. Some people with type 2 diabetes or gestational diabetes also take insulin to improve their blood sugar.
- Non-insulin injectable medicines.
- Oral medicine.
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Last reviewed by Susan Marchezak, CRNP on 2024-03-28.