Diabetes mellitus type 2

Type 2 diabetes develops when the body becomes resistant to insulin or when the pancreas is unable to produce enough insulin. Exactly why this happens is unknown, although genetics and environmental factors, such as being overweight and inactive, seem to be contributing factors.

How insulin works

Insulin is a hormone that comes from the gland situated behind and below the stomach (pancreas).

• The pancreas secretes insulin into the bloodstream.
• The insulin circulates, enabling sugar to enter your cells.
• Insulin lowers the amount of sugar in your bloodstream.
• As your blood sugar level drops, so does the secretion of insulin from your pancreas.

The role of glucose

Glucose — a sugar — is a main source of energy for the cells that make up muscles and other tissues.

• Glucose comes from two major sources: food and your liver.
• Sugar is absorbed into the bloodstream, where it enters cells with the help of insulin.
• Your liver stores and makes glucose.
• When your glucose levels are low, such as when you haven't eaten in a while, the liver breaks down stored glycogen into glucose to keep your glucose level within a normal range.

In type 2 diabetes, this process doesn't work well. Instead of moving into your cells, sugar builds up in your bloodstream. As blood sugar levels increase, the insulin-producing beta cells in the pancreas release more insulin, but eventually these cells become impaired and can't make enough insulin to meet the body's demands.

In the much less common type 1 diabetes, the immune system mistakenly destroys the beta cells, leaving the body with little to no insulin.

Risk factors

Factors that may increase your risk of type 2 diabetes include:

• Weight. Being overweight is a main risk factor for type 2 diabetes. However, you don't have to be overweight to develop type 2 diabetes.
• Fat distribution. If you store fat mainly in the abdomen, you have a greater risk of type 2 diabetes than if you store fat elsewhere, such as in your hips and thighs. Your risk of type 2 diabetes rises if you're a man with a waist circumference above 40 inches (101.6 centimeters) or a woman with a waist that's greater than 35 inches (88.9 centimeters).
• Inactivity. The less active you are, the greater your risk of type 2 diabetes. Physical activity helps you control your weight, uses up glucose as energy and makes your cells more sensitive to insulin.
• Family history. The risk of type 2 diabetes increases if your parent or sibling has type 2 diabetes.
• Race. Although it's unclear why, people of certain races — including black, Hispanic, American Indian and Asian-American people — are more likely to develop type 2 diabetes than white people are.
• Age. The risk of type 2 diabetes increases as you get older, especially after age 45. That's probably because people tend to exercise less, lose muscle mass and gain weight as they age. But type 2 diabetes is also increasing dramatically among children, adolescents and younger adults.
• Prediabetes. Prediabetes is a condition in which your blood sugar level is higher than normal, but not high enough to be classified as diabetes. Left untreated, prediabetes often progresses to type 2 diabetes.
• Gestational diabetes. If you developed gestational diabetes when you were pregnant, your risk of developing type 2 diabetes increases. If you gave birth to a baby weighing more than 9 pounds (4 kilograms), you're also at risk of type 2 diabetes.
• Polycystic ovarian syndrome. For women, having polycystic ovarian syndrome — a common condition characterized by irregular menstrual periods, excess hair growth and obesity — increases the risk of diabetes.
• Areas of darkened skin, usually in the armpits and neck. This condition often indicates insulin resistance.

Complications

Type 2 diabetes can be easy to ignore, especially in the early stages when you're feeling fine. But diabetes affects many major organs, including your heart, blood vessels, nerves, eyes and kidneys. Controlling your blood sugar levels can help prevent these complications.

Although long-term complications of diabetes develop gradually, they can eventually be disabling or even life-threatening. Some of the potential complications of diabetes include:

• Heart and blood vessel disease. Diabetes dramatically increases the risk of heart disease, stroke, high blood pressure and narrowing of blood vessels (atherosclerosis).

• Nerve damage (neuropathy). Excess sugar can cause tingling, numbness, burning or pain that usually begins at the tips of the toes or fingers and gradually spreads upward. Eventually, you may lose all sense of feeling in the affected limbs.

  Damage to the nerves that control digestion can cause problems with nausea, vomiting, diarrhea or constipation. For men, erectile dysfunction may be an issue.

• Kidney damage. Diabetes can sometimes lead to kidney failure or irreversible end-stage kidney disease, which may require dialysis or a kidney transplant.
• Eye damage. Diabetes increases the risk of serious eye diseases, such as cataracts and glaucoma, and may damage the blood vessels of the retina, potentially leading to blindness.
• Slow healing. Left untreated, cuts and blisters can become serious infections, which may heal poorly. Severe damage might require toe, foot or leg amputation.
• Hearing impairment. Hearing problems are more common in people with diabetes.
• Skin conditions. Diabetes may leave you more susceptible to skin problems, including bacterial and fungal infections.
• Sleep apnea. Obstructive sleep apnea is common in people with type 2 diabetes. Obesity may be the main contributing factor to both conditions. Treating sleep apnea may lower your blood pressure and make you feel more rested, but it's not clear whether it helps improve blood sugar control.
• Alzheimer's disease. Type 2 diabetes seems to increase the risk of Alzheimer's disease, though it's not clear why. The worse your blood sugar control, the greater the risk appears to be.

Prevention

Healthy lifestyle choices can help prevent type 2 diabetes, and that's true even if you have diabetes in your family. If you've already received a diagnosis of diabetes, you can use healthy lifestyle choices to help prevent complications. If you have prediabetes, lifestyle changes can slow or stop the progression to diabetes.

A healthy lifestyle includes:

• Eating healthy foods. Choose foods lower in fat and calories and higher in fiber. Focus on fruits, vegetables and whole grains.
• Getting active. Aim for a minimum of 30 to 60 minutes of moderate physical activity — or 15 to 30 minutes of vigorous aerobic activity — on most days. Take a brisk daily walk. Ride a bike. Swim laps. If you can't fit in a long workout, spread your activity throughout the day.
• Losing weight. If you're overweight, losing 5 to 10 percent of your body weight can reduce the risk of diabetes. To keep your weight in a healthy range, focus on permanent changes to your eating and exercise habits. Motivate yourself by remembering the benefits of losing weight, such as a healthier heart, more energy and improved self-esteem.
• Avoiding being sedentary for long periods. Sitting still for long periods can increase your risk of type 2 diabetes. Try to get up every 30 minutes and move around for at least a few minutes.

Sometimes medication is an option as well. Metformin (Glucophage, Glumetza, others), an oral diabetes medication, may reduce the risk of type 2 diabetes. But even if you take medication, healthy lifestyle choices remain essential for preventing or managing diabetes.

Type 2 diabetes is usually diagnosed using the:

• Glycated hemoglobin (A1C) test. This blood test indicates your average blood sugar level for the past two to three months. Normal levels are below 5.7 percent, and a result between 5.7 and 6.4 percent is considered prediabetes. An A1C level of 6.5 percent or higher on two separate tests means you have diabetes.

If the A1C test isn't available, or if you have certain conditions — such as an uncommon form of hemoglobin (known as a hemoglobin variant) — that interfere with A1C test, your doctor may use the following tests to diagnose diabetes:

• Random blood sugar test. Blood sugar values are expressed in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Regardless of when you last ate, a blood sample showing that your blood sugar level is 200 mg/dL (11.1 mmol/L) or higher suggests diabetes, especially if you also have signs and symptoms of diabetes, such as frequent urination and extreme thirst.

• Fasting blood sugar test. A blood sample is taken after an overnight fast. A reading of less than 100 mg/dL (5.6 mmol/L) is normal. A level from 100 to 125 mg/dL (5.6 to 6.9 mmol/L) is considered prediabetes.

  If your fasting blood sugar is 126 mg/dL (7 mmol/L) or higher on two separate tests, you have diabetes.

• Oral glucose tolerance test. This test is less commonly used than the others, except during pregnancy. You'll need to fast overnight and then drink a sugary liquid at the doctor's office. Blood sugar levels are tested periodically for the next two hours.

  A blood sugar level less than 140 mg/dL (7.8 mmol/L) is normal. A reading between 140 and 199 mg/dL (7.8 mmol/L and 11.0 mmol/L) indicates prediabetes. A reading of 200 mg/dL (11.1 mmol/L) or higher after two hours suggests diabetes.

The American Diabetes Association recommends routine screening for type 2 diabetes beginning at age 45, especially if you're overweight. If the results are normal, repeat the test every three years. If the results are borderline, ask your doctor when to come back for another test.

Screening is also recommended for people who are under 45 and overweight if there are other heart disease or diabetes risk factors present, such as a sedentary lifestyle, a family history of type 2 diabetes, a personal history of gestational diabetes or blood pressure above 140/90 millimeters of mercury (mm Hg).

If you're diagnosed with diabetes, the doctor may do other tests to distinguish between type 1 and type 2 diabetes — since the two conditions often require different treatments.

After the diagnosis

A1C levels need to be checked between two and four times a year. Discuss your target A1C goal with your doctor, as it may vary depending on your age and other factors. For most people, the American Diabetes Association recommends an A1C level below 7 percent.

An elevated A1C level may signal the need for a change in your medication, meal plan or activity level.

In addition to the A1C test, your doctor will measure your blood pressure and take blood and urine samples periodically to check your cholesterol levels, thyroid function, liver function and kidney function. Regular eye and foot exams also are important.

Management of type 2 diabetes includes:

• Weight loss
• Healthy eating
• Regular exercise
• Possibly, diabetes medication or insulin therapy
• Blood sugar monitoring

These steps will help keep your blood sugar level closer to normal, which can delay or prevent complications.

Weight loss

Losing weight can lower your blood sugar levels. Losing just 5 to 10 percent of your body weight can make a difference, although a sustained weight loss of 7 percent or more of your initial weight seems to be ideal. That means someone who weighs 180 pounds (82 kilograms) would need to lose a little less than 13 pounds (5.9 kilograms) to make an impact on blood sugar levels.

Controlling portions and eating healthy foods are simple ways to start taking weight off.

Healthy eating

Contrary to popular perception, there's no specific diabetes diet. However, it's important to center your diet around:

• Fewer calories
• Fewer refined carbohydrates, especially sweets
• Fewer foods containing saturated fats
• More vegetables and fruits
• More foods with fiber

A registered dietitian can help you put together a meal plan that fits your health goals, food preferences and lifestyle. He or she can also teach you how to monitor your carbohydrate intake and let you know about how many carbohydrates you need to eat with your meals and snacks to keep your blood sugar levels more stable.

Physical activity

Everyone needs regular aerobic exercise, and people who have type 2 diabetes are no exception. Get your doctor's OK before starting an exercise program. Choose activities you enjoy, such as walking, swimming and biking, so that you can make them part of your daily routine.

Aim for at least 30 to 60 minutes of moderate (or 15 to 30 minutes of vigorous) aerobic exercise most days of the week. A combination of exercises — aerobic exercises, such as walking or dancing on most days, combined with resistance training, such as weightlifting or yoga twice a week — offers more benefits than either type of exercise alone.

Remember that physical activity lowers blood sugar. Check your blood sugar level before any activity. You might need to eat a snack before exercising to help prevent low blood sugar if you take diabetes medications that lower your blood sugar.

It's also important to reduce the amount of time you spend in inactive activities, such as watching TV. Try to move around a bit every 30 minutes.

Monitoring your blood sugar

Depending on your treatment plan, you may need to check and record your blood sugar level every now and then or, if you're on insulin, multiple times a day. Ask your doctor how often he or she wants you to check your blood sugar. Careful monitoring is the only way to make sure that your blood sugar level remains within your target range.

Diabetes medications and insulin therapy

Some people who have type 2 diabetes can achieve their target blood sugar levels with diet and exercise alone, but many also need diabetes medications or insulin therapy. The decision about which medications are best depends on many factors, including your blood sugar level and any other health problems you have. Your doctor might combine drugs from different classes to help you control your blood sugar in several different ways.

Examples of possible treatments for type 2 diabetes include:

• Metformin (Glucophage, Glumetza, others). Generally, metformin is the first medication prescribed for type 2 diabetes. It works by lowering glucose production in the liver and improving your body's sensitivity to insulin so that your body uses insulin more effectively.

  Nausea and diarrhea are possible side effects of metformin. These side effects may go away as your body gets used to the medicine or if you take the medicine with a meal. If metformin and lifestyles changes aren't enough to control your blood sugar level, other oral or injected medications can be added.

• Sulfonylureas. These medications help your body secrete more insulin. Examples include glyburide (DiaBeta, Glynase), glipizide (Glucotrol) and glimepiride (Amaryl). Possible side effects include low blood sugar and weight gain.
• Meglitinides. These medications — such as repaglinide (Prandin) and nateglinide (Starlix) — work like sulfonylureas by stimulating the pancreas to secrete more insulin, but they're faster acting, and the duration of their effect in the body is shorter. They also have a risk of causing low blood sugar and weight gain.
• Thiazolidinediones. Like metformin, these medications — including rosiglitazone (Avandia) and pioglitazone (Actos) — make the body's tissues more sensitive to insulin. These drugs have been linked to weight gain and other more-serious side effects, such as an increased risk of heart failure and anemia. Because of these risks, these medications generally aren't first-choice treatments.
• DPP-4 inhibitors. These medications — sitagliptin (Januvia), saxagliptin (Onglyza) and linagliptin (Tradjenta) — help reduce blood sugar levels, but tend to have a very modest effect. They don't cause weight gain, but may cause joint pain and increase your risk of pancreatitis.

• GLP-1 receptor agonists. These injectable medications slow digestion and help lower blood sugar levels. Their use is often associated with weight loss. Possible side effects include nausea and an increased risk of pancreatitis.

  Exenatide (Byetta, Bydureon), liraglutide (Victoza) and semaglutide (Ozempic) are examples of GLP-1 receptor agonists. Recent research has shown that liraglutide and semaglutide may reduce the risk of heart attack and stroke in people at high risk of those conditions.

• SGLT2 inhibitors. These drugs prevent the kidneys from reabsorbing sugar into the blood. Instead, the sugar is excreted in the urine. Examples include canagliflozin (Invokana), dapagliflozin (Farxiga) and empagliflozin (Jardiance).

  Medications in this drug class may reduce the risk of heart attack and stroke in people with a high risk of those conditions. Side effects may include vaginal yeast infections, urinary tract infections, low blood pressure, and a higher risk of diabetic ketoacidosis. Canagliflozin, but not the other drugs in the class, has been associated with increased risk of lower limb amputation.

• Insulin. Some people who have type 2 diabetes need insulin therapy. In the past, insulin therapy was used as a last resort, but today it's often prescribed sooner because of its benefits. Low blood sugar (hypoglycemia) is a possible side effect of insulin.

  Normal digestion interferes with insulin taken by mouth, so insulin must be injected. Depending on your needs, your doctor may prescribe a mixture of insulin types to use throughout the day and night. There are many types of insulin, and they each work in a different way.

  Often, people with type 2 diabetes start using insulin with one long-acting shot at night, such as insulin glargine (Lantus) or insulin detemir (Levemir). Discuss the pros and cons of different drugs with your doctor. Together you can decide which medication is best for you after considering many factors, including costs and other aspects of your health.

In addition to diabetes medications, your doctor might prescribe low-dose aspirin therapy as well as blood pressure and cholesterol-lowering medications to help prevent heart and blood vessel disease.

Bariatric surgery

If you have type 2 diabetes and your body mass index (BMI) is greater than 35, you may be a candidate for weight-loss surgery (bariatric surgery). Dramatic improvements in blood sugar levels are often seen in people with type 2 diabetes after bariatric surgery, depending on the procedure performed. Surgeries that bypass a portion of the small intestine have more of an effect on blood sugar levels than do other weight-loss surgeries.

Surgery drawbacks include its high cost and risks, including a small risk of death. It also requires drastic lifestyle changes. Long-term complications may include nutritional deficiencies and osteoporosis.

Pregnancy

Women with type 2 diabetes may need to alter their treatment during pregnancy. Many women will require insulin therapy during pregnancy. Cholesterol-lowering medications, aspirin and some blood pressure drugs can't be used during pregnancy.

If you have diabetic retinopathy, it may worsen during pregnancy. Visit your ophthalmologist during the first trimester of your pregnancy and at one year postpartum.

Signs of trouble

Because so many factors can affect your blood sugar, problems sometimes arise that require immediate care, such as:

• High blood sugar (hyperglycemia). Lots of things can cause your blood sugar to rise, including eating too much, being sick or not taking enough glucose-lowering medication. Watch for signs and symptoms of high blood sugar — frequent urination, increased thirst, dry mouth, blurred vision, fatigue and nausea — and check your blood sugar if necessary.

• Hyperglycemic hyperosmolar nonketotic syndrome (HHNS). This life-threatening condition includes a blood sugar reading higher than 600 mg/dL (33.3 mmol/L). Your blood sugar meter may not provide an accurate reading at this level or it may just read "high." HHNS can cause dry mouth, extreme thirst, drowsiness, confusion, dark urine and convulsions.

  HHNS is caused by sky-high blood sugar that turns blood thick and syrupy. It tends to be more common in older people with type 2 diabetes, and it's often preceded by an illness or infection. Call your doctor or seek immediate medical care if you have signs or symptoms of this condition.

• Increased ketones in your urine (diabetic ketoacidosis). If your cells are starved for energy, your body may begin to break down fat. This produces toxic acids known as ketones, which occur more commonly in people with type 1 diabetes.

  Watch for thirst or a very dry mouth, frequent urination, vomiting, shortness of breath, fatigue and fruity-smelling breath, and if you notice these signs and symptoms, consult your doctor right away or seek emergency care.

• Low blood sugar (hypoglycemia). If your blood sugar level drops below your target range, it's known as low blood sugar (hypoglycemia). Your blood sugar level can drop for many reasons, including skipping a meal, unintentionally taking more medication than usual or getting more physical activity than normal.

  Watch for signs and symptoms of low blood sugar — sweating, shakiness, weakness, hunger, irritability, dizziness, headache, blurred vision, heart palpitations, slurred speech, drowsiness and confusion.

  If you have signs or symptoms of low blood sugar, drink or eat something that will quickly raise your blood sugar level — fruit juice, glucose tablets, hard candy, regular (not diet) soda or another source of sugar. Retest your blood in 15 minutes to be sure your blood glucose levels have normalized.

  If they haven't, treat again and retest in another 15 minutes. If you lose consciousness, a family member or close contact may need to give you an emergency injection of glucagon, a hormone that stimulates the release of sugar into the blood.

Lifestyle and home remedies

Careful management of type 2 diabetes can reduce your risk of serious — even life-threatening — complications. Consider these tips:

• Commit to managing your diabetes. Learn all you can about type 2 diabetes. Make healthy eating and physical activity part of your daily routine. Establish a relationship with a diabetes educator, and ask your diabetes treatment team for help when you need it.
• Identify yourself. Wear a necklace or bracelet that says you have diabetes, especially if you take insulin or other blood sugar-lowering medication.
• Schedule a yearly physical exam and regular eye exams. Your regular diabetes checkups aren't meant to replace regular physicals or routine eye exams. 

• Keep your vaccinations up to date. High blood sugar can weaken your immune system. Get a flu shot every year. Your doctor will likely also recommend the pneumonia vaccine.

  The Centers for Disease Control and Prevention (CDC) also recommends the hepatitis B vaccination if you haven't previously received this vaccine and you're an adult between ages 19 and 59 with type 1 or type 2 diabetes. The CDC advises vaccination as soon as possible after diagnosis with type 1 or type 2 diabetes. If you are age 60 or older, have diabetes and haven't previously received the vaccine, talk to your doctor about whether it's right for you.

• Take care of your teeth. Diabetes may leave you prone to more-serious gum infections. Brush and floss your teeth regularly and schedule recommended dental exams. Consult your dentist right away if your gums bleed or look red or swollen.
• Pay attention to your feet. Wash your feet daily in lukewarm water, dry them gently, especially between the toes, and moisturize them with lotion. Check your feet every day for blisters, cuts, sores, redness and swelling. Consult your doctor if you have a sore or other foot problem that isn't healing. 
• Keep your blood pressure and cholesterol under control. Eating healthy foods and exercising regularly can go a long way toward controlling high blood pressure and cholesterol. Medication also may be needed.
• If you smoke or use other types of tobacco, ask your doctor to help you quit.Smoking increases your risk of various diabetes complications. Talk to your doctor about ways to stop smoking or using other types of tobacco.

• If you drink alcohol, do so responsibly. Alcohol, as well as drink mixers, can cause either high or low blood sugar, depending on how much you drink and if you eat at the same time. If you choose to drink, do so in moderation and always with a meal.

  The recommendation is no more than one drink daily for women, no more than two drinks daily for men age 65 and younger, and one drink a day for men over 65. If you're on insulin or other medications that lower your blood sugar, check your blood sugar before you go to sleep to make sure you're at a safe level.

Alternative medicine

Numerous alternative medicine treatments claim to help people with diabetes. Studies haven't provided enough evidence to recommend any alternative therapies for blood sugar management.

If you decide to try an alternative therapy, don't stop taking the medications that your doctor has prescribed. Be sure to discuss the use of any of these therapies with your doctor to make sure that they won't cause adverse reactions or interact with your medications.

No treatments — alternative or conventional — can cure diabetes. So it's critical that people who are using insulin therapy for diabetes don't stop using insulin unless directed to do so by their physicians.

Coping and support

Type 2 diabetes is a serious disease, and following your diabetes treatment plan takes round-the-clock commitment. But your efforts are worthwhile because following your treatment plan can reduce your risk of complications.

Anxiety and depression are more common in people who have diabetes. Talking to a counselor or therapist may help you cope with the lifestyle changes that come with a type 2 diabetes diagnosis. You may find encouragement and understanding in a type 2 diabetes support group.

Although support groups aren't for everyone, they can be good sources of information. Group members often know about the latest treatments and tend to share their own experiences or helpful information, such as where to find carbohydrate counts for your favorite takeout restaurant. If you're interested, your doctor may be able to recommend a group in your area.

Or, you can visit the American Diabetes Association website to check out local activities and support groups for people with type 2 diabetes. The American Diabetes Association also offers online information and online forums where you can chat with others who have diabetes. You can also call the organization at 800-DIABETES (800-342-2383).