Diabetes

Causes

To understand diabetes, it’s important to understand how your body normally uses glucose.

How insulin works

Insulin is a hormone produced by a gland located behind and below the stomach (the pancreas).

• The pancreas releases insulin into the bloodstream.
• Insulin circulates, allowing 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, or sugar, is a main source of energy for the cells that make up your muscles and other tissues.

• Glucose comes from two main sources: food and your liver.
• Sugar is absorbed into your 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 for a long time, your liver breaks down stored glycogen and converts it into glucose. This keeps your glucose level within a normal range.

The exact cause of most types of diabetes is not yet known. In all cases, sugar accumulates in the bloodstream. This is due to the pancreas not producing enough insulin. Both type 1 and type 2 diabetes can be caused by a combination of genetic or environmental factors. These factors are not yet clear.

Risk factors

Diabetes risk factors depend on the type. Family history plays a role in all types. Environmental factors and geography can also increase the risk of type 1 diabetes.

Family members of people with type 1 diabetes are sometimes screened for diabetes autoantibodies. If you have these autoantibodies, you are at increased risk of developing type 1 diabetes. However, not everyone with these autoantibodies develops diabetes.

Belonging to certain racial or ethnic groups can also increase the likelihood of developing type 2 diabetes. Some people, including Black people, Hispanic/Latino people, American Indians, and Asian Americans, are more likely to develop it, although the reason is not clearly understood.

Prediabetes, type 2 diabetes, and gestational diabetes are also common in people who are overweight or obese.

Complications

Long-term complications of diabetes develop gradually. The longer you have diabetes — and the less controlled your blood sugar — the higher the risk of complications. Eventually, diabetes complications can be disabling or even life-threatening. In fact, prediabetes can lead to type 2 diabetes. Potential complications include:

• Cardiovascular disease. Diabetes significantly increases the risk of many heart problems. These can include coronary artery disease with chest pain (angina), heart attack, stroke, and narrowing (atherosclerosis) of the arteries. If you have diabetes, you are more likely to have heart disease or stroke.

• Diabetic nerve damage (neuropathy). Excess sugar can damage the walls of the tiny blood vessels (capillaries) that nourish your nerves, especially in your legs. This can cause tingling, numbness, burning, or pain that usually begins at the tips of your toes or fingers and gradually spreads upward.

  Nerve damage related to digestion can cause problems such as nausea, vomiting, diarrhea, or constipation. For men, it may lead to erectile dysfunction.

• Diabetic kidney damage (nephropathy). The kidneys contain millions of tiny blood vessel clusters (glomeruli) that filter waste from your blood. Diabetes can damage this delicate filtering system in the kidneys.
• Diabetic eye damage (retinopathy). Diabetes can damage the blood vessels in your eyes. This can lead to blindness.
• Foot damage. Nerve damage in the foot or poor blood flow to the foot increases the risk of many foot complications.
• Skin and oral diseases. Diabetes can also make you more susceptible to skin problems, including bacterial and fungal infections.
• Hearing impairment. Hearing problems are more common in people with diabetes.
• Alzheimer’s disease. Type 2 diabetes may increase the risk of dementia, such as Alzheimer’s disease.
• Diabetes-related depression. Symptoms of depression are common in people with type 1 and type 2 diabetes.

Complications of gestational diabetes

Most women with gestational diabetes deliver healthy babies. However, untreated high blood sugar levels can cause problems for both you and your baby.

Complications for your baby due to gestational diabetes include:

• Excessive growth. Excess glucose can pass through the placenta. This excess glucose stimulates your baby’s pancreas to produce more insulin. This can lead to your baby growing too large, causing difficult delivery and sometimes requiring a C-section.
• Low blood sugar. Babies of mothers with gestational diabetes sometimes develop low blood sugar shortly after birth. This is due to their increased insulin production.
• Developing type 2 diabetes later in life. Children of mothers with gestational diabetes are at higher risk of obesity and type 2 diabetes later in life.
• Death. Untreated gestational diabetes can lead to infant death, either before or shortly after birth.

Complications for the mother due to gestational diabetes include:

• Preeclampsia. Symptoms of this condition include high blood pressure, excess protein in the urine, and swelling in the legs and feet.
• Gestational diabetes. If you’ve had gestational diabetes once, you’re likely to develop it again in future pregnancies.

Prevention

Type 1 diabetes cannot be prevented. However, healthy lifestyle choices that help treat prediabetes, type 2 diabetes, and gestational diabetes can also help prevent these conditions. These choices include:

• Eating healthy foods. Choose foods low in fat and calories and high in fiber. Focus on fruits, vegetables, and whole grains. Eat a variety of foods to avoid boredom.
• Getting more physical activity. Aim for about 30 minutes of moderate aerobic activity most days of the week. Or aim for 150 minutes of moderate aerobic activity weekly. For example, enjoy a brisk walk daily. If a long workout isn’t feasible, break up your exercise into shorter periods throughout the day.

• Losing excess weight. If you’re overweight, you can reduce your risk of diabetes by losing 7% of your body weight. For example, if you weigh 200 pounds (90.7 kilograms), losing 14 pounds (6.4 kg) can reduce your risk of diabetes.

  However, avoid losing weight during pregnancy. Pregnant women should talk to their doctor about appropriate weight gain for their health during pregnancy.

  To keep your weight within a healthy range, focus on making long-term changes to your eating and exercise habits. Remember the benefits of weight loss, such as maintaining heart health, having more energy, and boosting self-esteem.

Medications are sometimes an option. Oral diabetes medications such as metformin (Glumetza, Fortamet, and others) may reduce the risk of type 2 diabetes. However, healthy lifestyle choices are important. If you have prediabetes, have your blood sugar checked at least once a year to ensure you haven’t developed type 2 diabetes.