Diabetes Mellitus

What is diabetes mellitus?

Diabetes mellitus refers to a group of diseases that affect how your body uses blood sugar (glucose).

Glucose is essential for good health because it is the primary source of energy for the cells that make up your muscles and tissues.
Glucose is also the brain’s primary source of energy.
If you have diabetes, regardless of the type, it means there is too much glucose in your blood, although the causes may vary.
Too much glucose can cause serious health problems.
Chronic diabetes includes type 1 diabetes and type 2 diabetes.

Conditions associated with diabetes that may be reversible include:
• Prediabetes — when blood sugar levels are higher than normal but not yet high enough to be classified as diabetes.
• Gestational diabetes, which occurs during pregnancy but may go away after the baby is born.

What Are the Symptoms?

The symptoms of diabetes vary depending on how high your blood sugar level is.
Some people, especially those with prediabetes or type 2 diabetes, may not experience any symptoms at first.
In type 1 diabetes, symptoms tend to appear quickly and are more severe.

Some signs and symptoms of type 1 and type 2 diabetes are:

Thirst increases

Frequent urination

An intense feeling of hunger

Weight loss without a clear cause

The presence of ketones in the urine (ketones are byproducts of the breakdown of muscle and fat that occur when there is insufficient insulin available).

Fatigue

Easily offended

Blurred vision

Wounds that heal slowly.

Common infections, such as gum or skin infections and vaginal infections

Although type 1 diabetes can develop at any age, it usually appears during childhood or adolescence. Type 2 diabetes, which is more common, can develop at any age, although it is more frequently seen in people over the age of 40.

What causes diabetes mellitus?

To understand diabetes, you first need to understand how glucose is normally processed in the body.

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 and allows sugar to enter your cells.
• Insulin lowers the amount of sugar in the bloodstream.
• When blood sugar levels drop, insulin secretion from the pancreas also decreases.

The Role of Glucose

Glucose, a type of sugar, is a source of energy for the cells that make up muscles and other tissues.
• Glucose comes from two main sources: food and the liver.
• Sugar is absorbed into the bloodstream and then enters the cells with the help of insulin.
• The liver stores and produces glucose.
• When blood glucose levels are low—for example, when you haven’t eaten for a while—the liver breaks down stored glycogen into glucose to keep blood glucose levels within the normal range.

Causes of Type 1 Diabetes

The exact cause of type 1 diabetes is unknown.
What is known is that the immune system, which normally fights off harmful bacteria or viruses, attacks and destroys the insulin-producing cells in the pancreas.
This means you have very little insulin or none at all.
Instead of being transported into cells, sugar builds up in the bloodstream.
Type 1 is thought to be caused by a combination of genetic susceptibility and environmental factors, although many of these factors are still not fully understood.

Causes of prediabetes and type 2 diabetes

In prediabetes—which can progress to type 2 diabetes—and in type 2 diabetes, your cells become resistant to the effects of insulin, while the pancreas is unable to produce enough insulin to overcome this resistance.
Instead of entering the cells that need it for energy, sugar builds up in the bloodstream.
The exact cause of this condition remains unclear, although genetic and environmental factors are believed to play a role in the development of type 2 diabetes.
Being overweight is closely linked to the development of type 2 diabetes, but not everyone with type 2 diabetes is overweight.

Causes of gestational diabetes

During pregnancy, the placenta produces hormones to sustain the pregnancy.
These hormones make your cells more resistant to insulin.
Typically, the pancreas responds by producing enough additional insulin to overcome this resistance. However, sometimes the pancreas cannot meet this need.
When this happens, too little glucose enters the cells and too much remains in the blood, leading to gestational diabetes.

What are the risk factors?

Risk factors for diabetes depend on the type of diabetes.

Risk factors for type 1 diabetes

Although the exact cause of type 1 diabetes is unknown, factors that may indicate an increased risk include:

• Family History

Your risk increases if your parents or siblings have type 1 diabetes.

• Environmental Factors

Factors such as exposure to viral infections may play a role in type 1 diabetes.

• The presence of harmful immune system cells (autoantibodies).

Sometimes, family members of people with type 1 diabetes are tested for the presence of diabetes autoantibodies.

• Dietary Factors

The source page lists low vitamin D intake, early exposure to cow’s milk or cow’s milk-based formula, and exposure to cereal before 4 months of age. None of these factors has been proven to directly cause type 1 diabetes.

• Geography.

Certain countries, such as Finland and Sweden, have higher rates of type 1 diabetes.

Risk factors for prediabetes and type 2 diabetes

Researchers do not yet fully understand why some people develop prediabetes and type 2 diabetes, while others do not.
However, certain factors are known to increase the risk, including:

• Body Weight.

The more fat tissue you have, the more insulin-resistant your cells become.

• Less active.

The less active you are, the greater the risk. Physical activity helps control weight, uses glucose for energy, and makes cells more sensitive to insulin.

•Family history.

Your risk increases if your parents or siblings have type 2 diabetes.

• Race.

The source page states that, although the reason is not yet clear, people of certain racial groups—including Black people, Hispanics, Native Americans, and Asian Americans—are at higher risk.

• Age.

The risk increases with age. This may be because you tend to exercise less, lose muscle mass, and gain weight as you get older. However, type 2 diabetes is also rising sharply among children, adolescents, and younger adults.

• Gestational diabetes.

If you have gestational diabetes during pregnancy, your risk of developing prediabetes and type 2 diabetes later in life increases. If you give birth to a baby weighing more than 9 pounds (4 kilograms), you are also at risk of developing type 2 diabetes.

• Polycystic ovary syndrome.

In women, polycystic ovary syndrome—a common condition characterized by irregular menstrual cycles, excessive hair growth, and obesity—increases the risk of diabetes.

• High blood pressure.

Having blood pressure above 140/90 millimeters of mercury (mmHg) is associated with an increased risk of type 2 diabetes.

• Abnormal cholesterol and triglyceride levels.

If high-density lipoprotein (HDL)—or “good” cholesterol—levels are low, the risk of type 2 diabetes is higher. People with high triglyceride levels have an increased risk of type 2 diabetes.

Risk factors for gestational diabetes

Any pregnant woman can develop gestational diabetes, but some women are at greater risk than others.

Risk factors for gestational diabetes include: Although the exact cause of type 1 diabetes is unknown, factors that may indicate an increased risk include:

• Age.

Women over the age of 25 are at increased risk.

• Family or personal history.

Your risk increases if you have prediabetes, a precursor to type 2 diabetes, or if a close family member—such as a parent or sibling—has type 2 diabetes. The risk is also higher if you have had gestational diabetes in a previous pregnancy, given birth to a very large baby, or experienced a stillbirth with no clear cause.

• Body weight.

Being overweight before pregnancy increases the risk.

What are the complications of diabetes?

Long-term complications of diabetes develop gradually.
The longer you have diabetes and the less well-controlled your blood sugar is, the higher your risk of complications.
Ultimately, complications from diabetes can lead to disability or even be life-threatening.

Possible complications include:

Cardiovascular disease.

Diabetes significantly increases the risk of various cardiovascular problems, including coronary artery disease with chest pain (angina), heart attack, stroke, and narrowing of the arteries (atherosclerosis). If you have diabetes, you are at a higher risk of developing heart disease or having a stroke.

Nerve damage (neuropathy).

Excess sugar can damage the walls of small blood vessels (capillaries) that supply nutrients to the nerves, especially in the feet. This can cause tingling, numbness, a burning sensation, or pain that usually starts at the tips of the toes or fingers and gradually spreads upward. If left untreated, you may lose all sensation in the affected limbs. Nerve damage related to digestion can cause nausea, vomiting, diarrhea, or constipation. In men, this can lead to erectile dysfunction.

Kidney damage (nephropathy).

The kidneys contain millions of clusters of tiny blood vessels (glomeruli) that filter waste from the blood. Diabetes can damage this delicate filtration system. Severe damage can lead to kidney failure or irreversible end-stage kidney disease, which may require dialysis or a kidney transplant.

Eye damage (retinopathy).

Diabetes can damage the blood vessels in the retina (diabetic retinopathy), which can potentially lead to blindness. Diabetes also increases the risk of other serious eye conditions, such as cataracts and glaucoma.

Leg injury.

Nerve damage or poor blood flow in the feet increases the risk of various foot complications. If left untreated, cuts and blisters can develop into serious infections that are often difficult to heal. These infections may ultimately require amputation of the toes, foot, or leg.

Skin condition.

Diabetes can make you more susceptible to skin problems, including bacterial and fungal infections.

Hearing loss.

Hearing problems are more common among people with diabetes.

Alzheimer's disease.

Type 2 diabetes can increase the risk of Alzheimer's disease.

Prediabetes can progress to type 2 diabetes.

How is diabetes diagnosed?

Screening for type 1 diabetes, type 2 diabetes, and prediabetes

Glycated Hemoglobin (A1C) Test

This blood test shows your average blood sugar level over the past two to three months. It measures the percentage of blood sugar attached to hemoglobin, the oxygen-carrying protein in red blood cells.

The higher the blood sugar level, the more hemoglobin binds to sugar.
• An A1C level of 6.5 percent or higher on two separate tests indicates diabetes.
• An A1C level of 5.7–6.4 percent indicates prediabetes.
• An A1C level below 5.7 is considered normal.

Certain conditions can cause A1C test results to be inconsistent or inaccurate: if you are pregnant or have an uncommon form of hemoglobin (known as a hemoglobin variant), your doctor may use a different test.

Random Blood Sugar Test

Blood samples were collected at random times.
Regardless of when you last ate, a random blood sugar level of 200 milligrams per deciliter (mg/dL), or 11.1 millimoles per liter (mmol/L), or higher indicates a possible case of diabetes.

Fasting Blood Sugar Test

A blood sample was taken after an overnight fast.
Fasting blood sugar level:
• Less than 100 mg/dL (5.6 mmol/L) is normal.
• 100 to 125 mg/dL (5.6 to 6.9 mmol/L) is considered prediabetes.
• A level of 126 mg/dL (7 mmol/L) or higher on two separate tests indicates diabetes.

Oral Glucose Tolerance Test

For this test, you fast overnight, and then your fasting blood sugar level is measured.
Next, you drink a sugary solution, and your blood sugar levels are checked periodically over the next two hours.
Blood sugar levels two hours after a meal, as listed on the source page:
• Less than 140 mg/dL (7.8 mmol/L) is normal.
• A level between 140 and 199 mg/dL (7.8 mmol/L and 11.0 mmol/L) indicates prediabetes.
• A level above 200 mg/dL (11.1 mmol/L) indicates diabetes.

Urinalysis

If type 1 diabetes is suspected, your urine is tested for byproducts produced when muscle and fat tissues are used for energy because the body does not have enough insulin to use the available glucose (ketones).

How is diabetes mellitus treated?

No matter what type of diabetes you have, you need to be well-informed and have a good understanding of your condition. Make a commitment to managing your diabetes. Learn as much as you can about diabetes. Build a relationship with a diabetes educator, and ask your diabetes care team for help when you need it. Successful diabetes management depends on your adherence to the entire treatment plan: lifestyle changes and medication. In general, the management of all types of diabetes includes:

Lifestyle Changes

Healthy Eating Habits

Contrary to popular belief, there is no single diet specifically for diabetes.
You should focus your diet on more fruits, vegetables, and whole grains—foods that are rich in nutrients and fiber and low in fat and calories—and cut back on animal products, processed carbohydrates, and sugary foods.
Actually, this is a good meal plan for the whole family.
Sugary foods can be eaten occasionally, as long as they are factored into your meal plan.
A registered dietitian can help you create a meal plan tailored to your health goals, food preferences, and lifestyle.

Physical activity

Exercise lowers blood sugar levels by moving sugar into cells to be used as energy.
Exercise also increases insulin sensitivity, so the body needs less insulin to transport sugar into the cells.
Get your doctor’s approval to exercise. Then choose an activity you enjoy, such as walking, swimming, or biking. The most important thing is to make physical activity part of your daily routine.
Aim to do at least 30 minutes of aerobic exercise most days of the week. If you haven’t been active in a while, start slowly and increase your activity level gradually. If you’re overweight, losing just 7 percent of your body weight can make a significant difference in controlling your blood sugar.

Treatment

Insulin.

People with type 1 diabetes need insulin therapy to survive. Many people with type 2 diabetes or gestational diabetes also need insulin therapy.

Oral medication or other medications.

Sometimes other oral medications or injections are also prescribed. Some diabetes medications stimulate the pancreas to produce and release more insulin. Other medications inhibit the production and release of glucose from the liver, so you need less insulin to transport sugar into your cells. Still other medications inhibit the action of stomach or intestinal enzymes that break down carbohydrates, or make tissues more sensitive to insulin. The source page lists metformin (Glucophage, Glumetza, and others) as the medication typically prescribed first for type 2 diabetes.

Transplant.

For some people with type 1 diabetes, a pancreas transplant may be an option. If the pancreas transplant is successful, insulin therapy is no longer needed. However, transplants are not always successful, and the procedure carries serious risks. Immunosuppressant medications are required for life to prevent organ rejection. These medications can have serious side effects, including a high risk of infection, organ damage, and cancer.

Bariatric surgery.

Although it is not specifically considered a treatment for type 2 diabetes, people with type 2 diabetes who also have a body mass index greater than 35 may benefit from this surgery. People who undergo gastric bypass surgery experience significant improvements in their blood sugar levels. The source page states that the long-term risks and benefits of this procedure for type 2 diabetes are not yet known.

Management of Gestational Diabetes

• Controlling blood sugar levels is very important for maintaining the baby’s health and preventing complications during childbirth. In addition to maintaining a healthy diet and exercising, insulin or oral medication may be necessary in some cases.
• Monitor blood sugar levels during labor. If blood sugar levels rise, the baby may release high levels of insulin, which can cause low blood sugar immediately after birth.

Management of Prediabetes

• If you have prediabetes, making healthy lifestyle choices can help bring your blood sugar levels back to normal.
• Sometimes medications, such as metformin (Glucophage, Glumetza, and others), are also an option if you’re at high risk for diabetes—including when prediabetes worsens or if you have cardiovascular disease, fatty liver disease, or polycystic ovary syndrome.
• In other cases, medications to control cholesterol—particularly statins—and medications for high blood pressure are necessary.
However, choosing a healthy lifestyle remains the key.

Low blood sugar (hypoglycemia)

If blood sugar levels drop below the target range, this condition is called low blood sugar (hypoglycemia). Blood sugar levels can drop for various reasons, including skipping meals and engaging in more physical activity than usual. However, low blood sugar is most likely to occur if you are taking glucose-lowering medications that increase insulin secretion by the pancreas or if you are on insulin therapy.Check your blood sugar levels regularly and watch for the signs and symptoms of low blood sugar: sweating, trembling, weakness, hunger, dizziness, headache, blurred vision, heart palpitations, irritability, slurred speech, drowsiness, confusion, fainting, and seizures. The source page states that low blood sugar is treated with rapidly absorbed carbohydrates, such as fruit juice or glucose tablets.

Key steps for maintaining diabetes management

For all types of diabetes mellitus, here are the key steps to maintaining effective management:

Schedule an annual physical exam and regular eye exams.

Routine diabetes checkups are not intended to replace annual physical exams or routine eye exams. During a physical exam, the doctor looks for diabetes-related complications and screens for other medical issues. An eye specialist checks for signs of retinal damage, cataracts, and glaucoma.

Make sure your vaccinations are up to date.

High blood sugar can weaken the immune system. The source page recommends getting a flu shot every year, and your doctor may also recommend a pneumonia vaccine.

Pay attention to your feet.

Wash your feet every day with lukewarm water. Gently dry them, especially between your toes. Use lotion to moisturize, but not between your toes. Check your feet every day for blisters, cuts, open sores, redness, or swelling.

Control your blood pressure and cholesterol.

Eating a healthy diet and exercising regularly are very helpful in controlling high blood pressure and cholesterol. Medication may also be necessary.

Take care of your teeth.

Diabetes can make you more susceptible to serious gum infections. Brush your teeth and floss at least twice a day. If you have type 1 or type 2 diabetes, schedule regular dental checkups. See your dentist right away if your gums bleed, appear red, or are swollen.

If you smoke or use other forms of tobacco, ask your doctor for help in quitting.

Smoking increases the risk of various diabetes-related complications. Smokers with diabetes are more likely to die from cardiovascular disease than people with diabetes who do not smoke.

If you drink alcohol, do so responsibly.

Alcohol can cause high or low blood sugar, depending on how much you drink and whether you eat at the same time. If you choose to drink, do so only in moderation.

Take stress seriously.

Hormones produced by the body in response to prolonged stress can prevent insulin from working properly, causing blood sugar levels to rise and making you even more stressed. Set boundaries for yourself and prioritize your tasks. Learn relaxation techniques and get enough sleep.

Embrace your identity based on your condition.

Wear a tag or bracelet that indicates you have diabetes. Keep a glucagon kit nearby in case of a low blood sugar emergency, and make sure your friends and loved ones know how to use it.

How can it be prevented?

Type 1 diabetes cannot be prevented.

However, healthy lifestyle choices that help manage prediabetes, type 2 diabetes, and gestational diabetes can also help prevent them:
• Eat healthy food. Choose foods that are lower in fat and calories and higher in fiber. Focus on fruits, vegetables, and whole grains. Try to vary your meals to avoid getting bored.
• Improve physical activity. Aim for 30 minutes of moderate physical activity every day. Go for a brisk walk every day. Ride a bike. Swim a few laps. If you can’t exercise for a long period of time, break it up into shorter sessions spread out throughout the day.
• Reduce body weight. If you’re overweight, losing as little as 7 percent of your body weight—for example, 14 pounds (6.4 kilograms) if you weigh 200 pounds (90.9 kilograms)—can reduce your risk of diabetes. To keep your weight within a healthy range, focus on making permanent changes to your eating and exercise habits. Motivate yourself by keeping in mind the benefits of weight loss, such as a healthier heart, more energy, and increased self-confidence.
• Sometimes medication is also an option. Oral diabetes medications such as metformin (Glucophage, Glumetza, and others) can reduce the risk of type 2 diabetes—but healthy lifestyle choices remain important.
• Do health screening regularly, especially blood sugar tests. Check your blood sugar at least once a year to make sure you don't have type 2 diabetes.