HomeDiseases & ConditionsDiabetesDiabetes Mellitus: Causes, Symptoms, Diagnosis and Treatment

Diabetes Mellitus: Causes, Symptoms, Diagnosis and Treatment

What causes diabetes?

What is Diabetes Mellitus?

Diabetes mellitus (commonly known as simply “diabetes”) is a condition that occurs when your blood glucose, or blood sugar, levels are too high.

Glucose is a form of sugar which is the main source of energy for our bodies. It is found in most foods that contain carbohydrates, such as grains, fruits, starchy vegetables, and dairy products.

When you eat these foods, your blood stream carries the glucose around your body, where your cells convert it into energy. To break down the glucose so that it can be used for energy, your body needs insulin, a hormone produced by your pancreas.

When you have diabetes, your body either doesn’t produce enough insulin or it doesn’t use insulin properly. So, the glucose you eat will stay in your blood instead of being turned into energy. Overtime, having too much glucose in your blood can cause damage to many parts of your body.

Diabetes is the leading cause of kidney failure in the United States, accounting for 44 percent of all new kidney failure cases.

According to the National Institute of Diabetes and Digestive and Kidney Diseases, an estimated 23 million people in the U.S are diagnosed with diabetes, and 84 million American adults (aged 18 and older) have prediabetes.

Prediabetes means your blood sugar level is higher than normal, but not high enough to be classified as type 2 diabetes. If you have prediabetes, you are at much higher risk of getting type 2 diabetes.

Individuals with diabetes are at increased risk for serious health complications, including blindness, hypertension, heart disease, stroke, amputations, and kidney disease.

What Causes Diabetes?

The causes of diabetes vary depending on the type. There are three main types of diabetes: type 1, type 2, and gestational diabetes.

Type 1 diabetes

Type 1 diabetes is caused by an autoimmune reaction where the body’s immune system attacks the cells that produce insulin. As a result, the body produces very little or completely stop producing insulin.

Without enough insulin, glucose cannot enter the cells and remains in the bloodstream. People with type 1 diabetes need to take insulin every day to stay alive.

About 10 percent of all patients with diabetes have type 1 diabetes. Type 1 diabetes can occur at any age, but it is more common in children and young adults.

Risk factors for type 1 diabetes

Risk factors for type 1 diabetes are not properly understood yet. But having a family member with type 1 diabetes increases your risk for developing it.

Some lifestyle and environmental factors may also increase your chances of getting it. These include not getting enough vitamin D, exposure to certain viruses, and/or having other autoimmune diseases such as celiac disease or autoimmune thyroid disease.

Type 2 diabetes

Type 2 diabetes is the most common type of diabetes, accounting for around 90 percent of all diabetes cases. This occurs when the body doesn’t produce enough insulin to function properly, or the body’s cells don’t react to insulin, a condition called insulin resistance.

This in turn causes glucose stays in the blood and isn’t used as fuel for energy, leading to high blood sugar levels.

Type 2 diabetes is commonly diagnosed in older adults, but is increasingly seen in adolescents and younger adults due to rising levels of obesity, physical inactivity and poor diet.

Type 2 diabetes do not need to depend on insulin treatment, but with proper diet, exercise and medications, people with type 2 diabetes can live normal, healthy lives.

Risk factors for type 2 diabetes

Several risk factors that have been associated with type 2 diabetes include:

  • Overweight
  • Increasing age
  • High blood pressure
  • Low HDL cholesterol and/or high triglycerides
  • Family history of type 2 diabetes
  • History of gestational diabetes

Gestational diabetes

Gestational diabetes is a type of diabetes that occurs during pregnancy. This occurs when your body can’t make enough insulin during your pregnancy. These changes cause your body’s cells to use insulin less effectively.

During pregnancy, the placenta produces hormones to sustain your pregnancy. These hormones make your cells more resistant to insulin. As a result, too much glucose stays in your blood, resulting in gestational diabetes.

About 2 to 10 percent of all pregnant women in the U.S. are diagnosed with gestational diabetes.

Unlike type 1 and type 2 diabetes, gestational diabetes is only temporary and usually goes away after the baby is born. However, women who have had gestational diabetes have increased risk of developing type 2 diabetes later in life.

Risk factors for gestational diabetes

Any pregnant woman can develop gestational diabetes, but you may be at increased risk for gestational diabetes if you:

  • Are over age 25
  • Are overweight or obese
  • Have a family history of type 2 diabetes
  • Have previously given birth to a large baby (weighing more than 10lbs)

What are the Signs and Symptoms of Diabetes?

The common symptoms of diabetes include:

  • Frequent urination
    This occurs due to too much glucose stays in the body and your body tries to get rid of the excess glucose through your urine, causing you to urinate more often than usual.
  • Excessive thirst
    Since your body draw additional water out of your body, you will become dehydrated and feel the urge to drink more water to replace the fluids you have lost.
  • Fatigue
    Insulin is needed to transport glucose from blood into our cells to be used for energy. When there is not enough insulin, or the insulin isn’t working properly, the sugar in our blood can’t get into our cells and therefore our cells do not receive the energy they need. As a result, we feel tired.
  • Sudden weight loss
    This because your body isn’t able to get adequate energy from the food you eat. It start knock down fat and muscle tissue for energy.
  • Itching around the penis or vagina
    Diabetes can cause a higher glucose content in the urine which can therefore provide ideal conditions for yeast to grow and also diminishes the body’s ability to fight infection.
  • Blurred vision
    High blood sugar levels can affect your ability to see by causing the lens inside the eye to swell, resulting in temporary blurring of eyesight.
  • Slow wound healing
    High levels of blood glucose can cause nerve damage and affect blood flow, making it hard for blood to reach areas of the body affected by sores or wounds. This causes wound healing process become slowly.
  • Numbness of the hands and feet
    High blood sugar impairs blood flow to heart and because hands and feet are far from the heart, any problems with blood flow can leave hands and feet without enough circulation, resulting in feeling numbness or tingling.

Type 1 diabetes symptoms can slightly differ from symptoms of type 2 diabetes. In type 1 diabetes, the symptoms are usually obvious and develop very quickly, often over a few weeks.

In type 2 diabetes, symptoms will often develop gradually and may not always show symptoms at an earlier stage. Therefore, it’s important to talk to your doctor about your risk and to see if you should be tested for diabetes.

The American Diabetes Association (ADA) recommends that everyone aged 45 and over should be tested for diabetes, and if the results are normal, testing should be repeated every three years.

If you have prediabetes or have any of the risk factors for diabetes, testing should be done at an earlier age and more frequently.

Early diagnosis and treatment for diabetes can reduce the likelihood of developing complications later on.

How is Diabetes Diagnosed?

Diabetes is often diagnosed by a blood test. The tests done include:

Fasting glucose (FPG) test

The fasting plasma glucose test (FPG) is the preferred method for diagnosing diabetes because it is easy to do and less expensive than other tests.

This test requires fasting (not eating or drinking, except water) for at least eight hours before the test. It measures the glucose levels in your blood.

A fasting blood sugar level less than 100 mg/dL is normal. A fasting blood sugar level between 100 and 125 mg/dL is considered prediabetes. If it’s 126 mg/dL or higher means you have diabetes.

For the most reliable results, this test is usually done first thing in the morning, before breakfast.

A1C test

A1C test, also known as HbA1c test or hemoglobin A1c test, is a blood test that measures the average blood glucose levels over the past 2 to 3 months. This test is more convenient than the FPG test because no fasting is required before obtaining the blood sample. Test results are expressed as %A1c, representing glucose control over the last three months.

An A1C of 5.7% to 6.4% means that you have prediabetes. Diabetes is diagnosed when the A1C is 6.5% or higher.

Random blood sugar test

Random blood sugar test is a blood test that can be taken at any time, without fasting or no worry about what you have ate.

Regardless of when you last ate, a random glucose level of 200 mg/dL or higher means you have diabetes.

Oral glucose tolerance test (OGTT)

This test is similar to a fasting blood glucose test. In the oral glucose tolerance test, you have to fast overnight and then a fasting blood sugar level is measured. Then you’ll drink a sugary liquid, and your blood glucose levels are tested periodically for the next two hours.

In this way, your doctor can compare the before-and-after glucose levels contained in your plasma to see how well your body processed the sugar. These levels are measured in mg/dL.

A blood sugar level less than 140 mg/dL is normal. A reading between 140 and 199 mg/dL indicates prediabetes, and a blood sugar of 200 mg/dL or more after two hours indicates diabetes.

The OGTT can be used to diagnose diabetes, prediabetes, and gestational diabetes. It is more sensitive than the FPG test for diagnosing prediabetes. However, the OGTT is more expensive and is less convenient to administer.

How is Diabetes Treated?

Currently, there is no cure for either type 1 or type 2 diabetes, but it can be managed effectively through healthy eating, physical activity, and medication.

The goals of diabetes treatment are to keep blood glucose levels as near to normal as possible and prevent the development of diabetes-related complications.

Depending on what type of diabetes you have, your diabetes healthcare team will work with you to create a diabetes care plan that works for you.

Healthy eating

An important part of managing your blood sugar is to eat a healthy, balanced diet. People who have diabetes should eat foods that are high in fiber and low in fat and calories.

Choose fruits, vegetables, whole grains, beans, chicken or turkey without the skin, fish, lean meats, and nonfat or low-fat milk and cheese. Drink water instead of sugar-sweetened beverages.

Portion size is also very important in people with diabetes. In order to keep your blood sugar levels steady, try to eat small meals throughout the day.

A registered dietitian can help you create a meal plan that fits your health goals, food preferences and lifestyle. This will likely include carbohydrate counting, especially if you have type 1 diabetes.


Everyone needs regular exercise, and people who have diabetes are no exception. Exercise lowers your blood sugar level by moving sugar into your cells, where it’s used for energy.

Exercise also increases your sensitivity to insulin, which means your body needs less insulin to transport sugar to your cells.

Aim for at least 30 minutes or more of aerobic exercise most days of the week. Brisk walking, running and swimming are some good choices for this activity. If you haven’t been active for a while, start slowly and build up gradually.


In type 1 diabetes

People with type 1 diabetes must take insulin injection as a part of their treatment. Since their bodies can not produce insulin anymore, they need to take insulin everyday to keep their blood sugar levels within a healthy range.

Insulin injections are usually given by an injection pen, which is also known as an insulin pen or auto-injector. Sometimes, injections are given using an insulin syringe. Most people need two to four injections a day.

An insulin pump may also be an option. It is a small device that allows insulin to continuously flow into your bloodstream at a rate you can control.

This means you’re no longer need to give yourself injections, though you’ll need to monitor your blood glucose levels very closely to ensure you’re receiving the right amount of insulin.

In type 2 diabetes

If you have type 2 diabetes, sometimes eating right and exercising are not enough. Your doctor may give you oral medication to help control your blood glucose levels.

Metformin is usually the first medication prescribed for type 2 diabetes. It helps lower blood glucose levels by reducing the amount of glucose produced by the liver, and by increasing the sensitivity of muscle cells to insulin.

In some cases, insulin injections are needed if the blood glucose level remains too high despite taking medication.

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