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Similarities and Differences Between Type 1 and Type 2 Diabetes

Type 1 Vs Type 2 Diabetes

Similarities and differences between type 1 and type 2 diabetes are discussed in this post. 

Type 1 and Type 2 diabetes are diagnosed when the blood glucose cross above the normal limits. As the name suggests, Diabetes Mellitus refers to passing lots of sweet urine.

Both type 1 and type 2 diabetes are characterized by hyperglycemia (elevated plasma blood glucose), glucosuria (passing glucose in the urine), and either insulin deficiency or insulin resistance.

Type 1 Diabetes Mellitus patients usually have a total or subtotal insulin deficiency. Hence, these patients always require insulin.

On the other hand, insulin levels are usually normal or higher in patients with T2DM. However, there is resistance to insulin at the peripheral tissue levels.

What is Diabetes Mellitus?

It is essentially a group of metabolic disorders, characterized by an excessively high blood sugar level.

Blood glucose level is maintained by a hormone secreted from your pancreas, called insulin which brings your blood sugar level back to normal in case it goes too high.

A high blood sugar level can be because of either the deficiency of insulin or its improper utilization in the body.

Types of Diabetes Mellitus:

Diabetes has two main types:

  • Type 1 Diabetes.
  • Type 2 Diabetes.

People usually tend to get confused between these two types, because both types are chronic metabolic disorders that alter the way blood sugar level is regulated in your body, so the confusion is pretty reasonable.

Gestational diabetes is another type of diabetes that affects pregnant females. Other types of diabetes include secondary diabetes which occurs in patients who are on corticosteroids or after pancreatitis.

Similarities and Differences Between Type 1 and Type 2 Diabetes

Type 1 and Type 2 diabetes are pathologically different conditions. However, since clinical manifestations are the same, it may be difficult to differentiate between the two types.

When a young child presents in a state of DKA (diabetic ketoacidosis), the diagnosis can be very straightforward. Children with DKA and very high blood glucose have Type 1 diabetes until proven otherwise.

Similarly, a middle-aged person with a history of polyuria and polydipsia who is found to have borderline raised blood sugar has Type 2 diabetes until proven otherwise.

The following table summarizes the similarities between Type 1 and Type 2 Diabetes:


Type 1 Diabetes and Type 2 Diabetes

Blood SugarHigh
Sugar in urinePresent
SymptomsPolyuria, Polydipsia, Polyphagia
ComplicationsThis can occur in both types
InsulinMay be used to treat both types
Lifestyle interventionsA healthy diabetic diet and exercise are required for both types


T1DM vs T2DM definition:

Type 1 diabetes is an autoimmune complication as compared to type 2 diabetes in which insulin is not being used properly.

As a matter of fact, the actual difference between both types is that in type 1 your body’s immune cells are killing and targeting its own cells (beta cells found in the pancreas) while in type 2 your body is not utilizing insulin efficiently as it should.

In type 2 diabetes, although enough insulin is being produced by your body your cells are not capable of responding to it.

In type 1 diabetes, since beta cells are being destroyed by your own immune system, there are fewer beta cells left to produce enough insulin which can help maintain blood sugar levels.

Typically, the confusion is caused because of the common consequence of these two types which is hyperglycemia (high blood sugar level). But the mechanism by which this condition is induced is very different.


What causes Type 1 and Type 2 Diabetes Mellitus?

  • Type 1 diabetes:

The immune system in your body is the actual culprit behind the cause of type 1 diabetes. The immune system is in charge of eradicating foreign invaders, it essentially detects any foreign invader that is capable of harming your body and gets rid of it.

However, in type 1 diabetes, your immune system malfunctions and starts killing your own insulin-producing beta cells.

At the moment, it is not known why the immune system tends to act this way, but certain factors like exposure to viruses or pathogens and mutations in genes can be a possible reason behind this.

Nevertheless, the destruction of beta cells leads to inefficient and inadequate production of insulin and consequently hyperglycemia.

  • Type 2 diabetes:

Insulin resistance is found in people who are a victim of type 2 diabetes, although it is not known why some people tend to develop insulin resistance while others do not, having a sedentary life, being physically inactive, and being obese or overweight are considered potential reasons.

Even though Insulin is still being produced in people with type 2 diabetes but your body’s cells are not responding to it, which gives rise to an elevated blood sugar level.

In order to compensate for the inefficient response of cells towards insulin, the pancreas starts producing excessive insulin to bring your blood sugar level back to normal.


Risk Factors for Type 1 vs Type 2 Diabetes Mellitus:

  • Type 1 diabetes:

Factors stated below can lead to the development of type 1 diabetes:

  • Mutations in genes can be a risk factor for type 1 diabetes
  • Much more common among children and young adults. Still, type 1 can occur at any age
  • Having a family history of type 1 puts you at an increased risk for type 1 diabetes. However, T2DM is more commonly associated with a family history of Diabetes than T1DM.
  • The presence of autoantibodies can be a factor leading to the development of type 1 diabetes.
  • Type 2 diabetes:

The following factors can put you at a higher risk of type 2 diabetes:


Diagnosis of Type 1 vs Type 2 Diabetes mellitus:

Diagnosis of Diabetes Type 1 or Type 2 is made when either of the following criteria is met:

  • two consecutive fasting blood sugars exceeding 125 mg/dl, or
  • two random blood sugars (two hours postprandial blood sugars exceed 199 mg/dl, or
  • glycated hemoglobin exceeds 6.4 %, OR
  • one fasting or random blood glucose above the ranges mentioned, in symptomatic patients.

The diagnosis of T1DM and T2DM is mostly clinical. When a person develops diabetes, the following clinical parameters may be used to diagnose Type 1 vs Type 2 diabetes mellitus:


Type 1 Diabetes Mellitus

Type 2 Diabetes Mellitus

Age of onset

Usually young (Children)Older adults

Body Habitus

Thin and leanUsually Obese

Family history of diabetes

May be positiveStrongly positive

Metabolic syndrome


Blood sugars on diagnosis

Very highSlightly above the ranges

First Clinical Presentation

Drowsiness, Shortness of breath, abdominal pain, and dehydrationFatigue, polyuria, polydipsia, numbness, and tingling sensation

Diabetic ketoacidosis

Occurs and may be frequentRare

Insulin requirement

AlwaysOnly in advanced cases

Insulin dose

A very small dose requiredVery high doses required

Response to oral diabetes medicines


Insulin and C-peptide levels

Low or absentHigh

Anti-GAD and anti-Islet cell antibodies


Glycated Hemoglobin on diagnosis

Normal or slightly high despite very high blood sugarsHigh

Glycated hemoglobin test (HbA1c test):

In order to diagnose either of the two types of diabetes, a glycated hemoglobin test is used. This is also known as the HbA1c test. This test is used to measure the amount of glucose bound in your blood.

Red blood cells (RBCs) have a life span of 3 months in your body. The sugar in your blood binds to your hemoglobin (Hb) in red blood cells and this test shows the average level of glucose present in your blood bound to the RBCs for the previous 3 months.

4% to 5.6% is the normal range of HbA1c for people without diabetes. 5.7% to 6.4% is the range for people with prediabetes and an HbA1c level of 6.5% or above indicates diabetes.


Treatment of Type 1 Vs Type 2 Diabetes Mellitus:

  • Type 1 diabetes:

Since the problem is with the production of insulin and not its utilization, the most appropriate treatment for type 1 diabetes is the administration of insulin mainly because your body can respond to it efficiently.

Therefore, insulin can effectively work in your body and is used as a treatment of choice for type 1 diabetes.

Compared to patients with diabetes mellitus type 2, type 1 diabetic patients usually require low doses of insulin three or four times a day.

Small changes in the insulin dose may result in marked fluctuations in blood glucose in patients with T1DM compared to T2DM.

  • Type 2 diabetes:

Type 2 diabetes has a much more complicated treatment, as many factors might be contributing to its onset and progress.

People who are at an early stage of type 2 diabetes can be treated with proper lifestyle modifications.

Such modifications may include routine physical activity, following a healthy diet, and weight management.

In case these suggested lifestyle changes are not enough to treat type 2 diabetes then medications, such as metformin, can be used according to your doctor’s advice. Other oral diabetes medications may also be used depending on the good glucose levels.

In case insulin is required, patients usually require high doses compared to patients with T1DM. In addition, basal insulin alone can be used to treat patients with T2DM who are not well controlled with oral medications.


Symptoms of Diabetes Mellitus Type 1 and 2

Common symptoms of diabetes include:

The common symptoms between type 1 and type 2 diabetes are:

  • Unintended and unexplained weight loss
  • Frequent urination
  • Fatigue
  • Increased appetite
  • Weakness
  • Blurred vision
  • Slow-healing wounds
  • Recurrent infections
  • Pigmentation of skin
  • Excessive thirst
  • Mood swings

Symptoms of Diabetic ketoacidosis include abdominal pain, drowsiness, nausea, and vomiting. These symptoms are more common in patients with T1DM compared to patients with T2DM.

Which type of Diabetes is more common, Type 1 or type 2?

As compared to type 1 diabetes, type 2 is much more prevalent. This can be because most people are physically inactive and being obese or overweight can be contributing to the prevalence of type 2 diabetes.

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

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