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Diabetes Mellitus


Diabetes Mellitus is when the body does not make enough insulin or respond to insulin appropriately, resulting in abnormally high blood sugar (glucose) levels. Insulin is a hormone produced by the pancreas (an organ located behind the stomach that also produces digestive enzymes) that regulates blood glucose levels. The pancreas is stimulated to produce insulin by glucose in the circulation. Insulin facilitates the transport of glucose from the bloodstream to the cells. When glucose enters the cells, it is transformed into energy and consumed right away, or it is stored as fat or starch glycogen until it is needed. The underlying cause of diabetes millets differs depending on the type. However, regardless of the type of diabetes you have, it can cause an excess of sugar in your blood. Blood sugar levels that are too high can cause significant health problems.


It is further classified into four types:



Type 1 Diabetes Mellitus (T1DM) is a condition where the pancreas’ beta cells responsible for synthesizing insulin are destroyed. This condition occurs due to an autoimmune response that destroys insulin-producing cells, leading to an insulin deficiency.  Type 1 diabetes affects only about 5 to 10% of people with diabetes. It mainly develops in people before they reach the age of 30, but it can develop at any age.


Type 2 Diabetes Mellitus (T2DM) is a disease of multiple etiology and is generally defined as a condition leading to hyperglycemia due to disturbances in insulin action. The pancreas often produces insulin in type 2 diabetes, sometimes at higher-than-normal amounts, especially early on in the disease. However, because the body develops resistance to insulin's actions, there is insufficient insulin to meet the body's needs. The pancreas' ability to produce insulin decreases as type 2 diabetes worsens. It usually starts in individuals over 30 and becomes more common with age. 


This condition develops during pregnancy and is characterized by glucose intolerance which is usually asymptomatic; women suffering from GDM are most likely to develop diabetes mellitus after pregnancy, but it usually goes away once the baby is born.


It is characterized by blood glucose levels above average but not high enough to be labeled diabetes. Prediabetes, if uncontrolled, increases the risk of developing diabetes and certain heart diseases in the future. Diet and exercise can help you lose 5 to 10% of your body weight, lowering your chance of having diabetes in the future.


Type 1

The primary cause of type 1 diabetes is the initiation of autoimmunity. However, several genetic and non-genetic factors trigger autoimmunity and, hence, beta cells’ destruction.

Type 2

Genetic predisposition plays a significant role in causing it. For example, the offspring of a patient with type 2 diabetes has a greater probability of developing type 2 diabetes than the offspring of healthy individuals. Still, genetic factors alone cannot always be the sole cause of the disease. Type 2 diabetes is a multifactorial disease. A sedentary lifestyle and dietary patterns also contribute to the development of this disease. Furthermore, environmental factors such as viral infection, obesity, and a diet rich in refined carbohydrates and saturated fats may impact genetic factors to become more pronounced and, in turn, cause the development of type 2 diabetes mellitus.

Risk Factors

Type 1 Diabetes

Family History of Diabetes: If a parent or sibling has type 1 diabetes, you're at a higher risk.

Environmental Factors: Exposure to a viral disease is likely to play a role in type 1 diabetes.

Autoantibodies: The presence of diabetes autoantibodies are sometimes tested in family members of persons with type 1 diabetes. You have a higher chance of acquiring type 1 diabetes if you have these autoantibodies. However, not everyone with these autoantibodies develops diabetes.

Geographic Location:  Some countries have more excellent rates of type 1 diabetes than others. 

Type 2 Diabetes

Obesity: The more fatty tissue you have, the more insulin resistant your cells become.

Physical Activity: The lower your activity level, the higher your risk. Physical activity helps you lose weight by burning glucose for energy and making your cells more insulin sensitive.

Family History of Diabetes: If a parent or sibling has type 2 diabetes, you're at a higher risk.

Race or Ethnicity: According to research studies, certain people, such as Black, Hispanic, American Indian, and Asian Americans, are more vulnerable to type 2 diabetes.

Age: As you become older, your risk increases. This could be because you tend to exercise less, lose muscle mass, and gain weight.

Gestational Diabetes: If you had gestational diabetes while pregnant, you're more likely to acquire prediabetes and type 2 diabetes later in life.

Polycystic Ovarian Syndrome (PCOS): PCOS raises the risk of diabetes in women. PCOS is a common disorder characterized by irregular menstrual periods, excessive hair growth, and obesity.

High Blood Pressure: High blood pressure is often associated with an increased risk of type 2 diabetes when it exceeds 140/90 millimeters of mercury (mm Hg).

Abnormal Triglyceride and Cholesterol Levels: If you have low HDL levels or "good" cholesterol, you're more likely to develop type 2 diabetes. Triglycerides are a form of fat that circulates in the bloodstream. Type 2 diabetes is more likely in people with high triglyceride levels. Your doctor can determine your cholesterol and triglyceride levels.

Signs And Symptoms

Signs and symptoms of diabetes include:

  • Increased thirst
  • Weakness and feeling of tiredness
  • Blurred vision
  • Frequent feeling of hunger
  • Weight loss
  • Irritability
  • Ketones (waste products of  muscle and fat breakdown) in urine
  • Numbness and tingling sensation in the extremities
  • Slow-healing of sores and wounds
  • Frequent urination


The following tests are usually performed to diagnose diabetes. These include:

  • Glycated Hemoglobin (HbA1C) Test: measures the average blood glucose level for the past two to three months. The average values are less than 5.7 %; prediabetes values range from 5.7 to 6.4 %. Values for a diabetic patient are 6.7 % or higher. If the A1C test results are inconsistent, the test isn't available, or you have certain conditions that could make the A1C test inaccurate — such as being pregnant or having another  form of hemoglobin (known as a hemoglobin variant) — your doctor may use one of the following tests to diagnose diabetes.
  • Fasting Glucose Test:  determines fasting blood sugar levels, and the test is usually performed in the morning before breakfast.
  • Random Glucose Test: This test determines blood sugar level randomly.
  • Glucose Tolerance Test (GTT): You are often told to fast overnight for this test, and your fasting blood sugar level is measured then. Then blood glucose levels are checked two hours before and after drinking a glucose-rich drink.


Diet, exercise, and education are the keystones of diabetes treatment, and they're generally the first things patients with moderate diabetes are told to do. For overweight people, losing weight is essential for l People with type 1 diabetes (regardless of blood glucose levels) and those who continue to have higher blood glucose levels despite lifestyle adjustments. Those who have very high blood glucose levels require medication. The goal of diabetes treatment is to keep blood glucose levels as close to normal as possible since complications are less likely to develop if people with diabetes closely control their blood glucose levels.

Treatment of high blood pressure and cholesterol levels, which can contribute to circulation problems, can also help prevent some diabetic complications. People with diabetes should carry or wear an identification (such as a bracelet or tag) to alert health care providers that they have diabetes. This information enables health care providers to begin life-saving treatment as soon as possible, particularly in the event of an injury or a change in mental status.

Learning about diabetes, understanding how diet and exercise affect blood glucose levels, and avoiding complications are essential to those with diabetes. Your healthcare provider can advise managing your food, exercising, monitoring your blood glucose levels, and taking medications according to your treatment plan.


The Treatment of Diabetes mainly involves lifestyle and diet modification. However, some people with diabetes cannot regulate their blood glucose levels by lifestyle and dietary change alone. Therefore, medicinal treatment is required for such individuals, which involves the oral or intravenous administration of insulin. Insulin injections are necessary for type 1 diabetes to control blood glucose levels. Most patients with type 2 diabetes take oral medications to maintain their blood sugar levels. Still, some also need insulin or other injectable drugs. Metformin (Glumetza, Fortamet, and others) is the most commonly used hypoglycaemic medicine for type 2 diabetes.

SGLT2 ( Sodium-glucose Cotransporter-2) inhibitors such as canagliflozin, dapagliflozin, and empagliflozin are another type of drug that could be used. They function by preventing sugar from being reabsorbed into the bloodstream by the kidneys. The sugar is instead eliminated in the urine.


Diabetes affects blood vessels, narrowing them and thus reducing blood flow. Since blood vessels throughout the body are impacted, people with diabetes may experience a variety of complications. Many organs can be damaged, including the following:

  • Strokes may be caused by bleeding in the brain.
  • Diabetic retinopathy affects the eyes, resulting in blindness.
  • May affect the heart, resulting in a heart attack
  • Diabetic nephropathy affects the kidneys, resulting in chronic kidney disease.
  • Nerve damage (diabetic neuropathy) causes a loss of sensation in the feet.
  • People with diabetes mellitus are more susceptible to bacterial and fungal infections because high blood glucose levels disrupt their immune systems.


  • Eating a Healthy Diet: Consuming nutritious foods low in fat and calories and high in fiber. Fruits, vegetables, and whole grains should be given priority.
  • Increase your Physical Activity: Aim for roughly 30 minutes of moderate aerobic exercise most days of the week, or at least 150 minutes per week.
  • Lose Weight: If you're overweight, even dropping 7% of your body weight can lower your risk of developing diabetes.
  • Don't strive to lose weight when pregnant. Consult your doctor about how much weight you should gain during your pregnancy.
  • Focus on long-term improvements to your activity and dietary habits to maintain a healthy weight, keeping in mind the advantages of losing weight, such as a healthier heart, more incredible energy, and improved self-esteem, to keep yourself motivated.
  • Medication is sometimes an option, although good lifestyle choices are still important. Check your blood sugar at least once a year to ensure you don't have type 2 diabetes.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 16, 2023.


Diabetes Mellitus - StatPearls - NCBI Bookshelf (,endocrinopathies%2C%20steroid%20use%2C%20etc.

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