Diabetes: The differences between types 1 and 2

Diabetes, or diabetes mellitus (DM), is a metabolic disorder in which the body cannot properly store and use sugar.

It affects the body's ability to use glucose, a type of sugar found in the blood, as fuel. This happens because the body does not produce enough insulin, or the cells do not correctly respond to insulin to use glucose as energy.
Insulin is a type of hormone produced by the pancreas to regulate how blood sugar becomes energy. An imbalance of insulin or resistance to insulin causes diabetes.
Diabetes is linked to a higher risk of cardiovascular disease, kidney disease, vision loss, neurological conditions, and damage to blood vessels and organs.
There is type 1, type 2, and gestational diabetes. They have different causes and risk factors, and different lines of treatment.
This article will compare the similarities and differences of types 1 and 2 diabetes.
Gestational diabetes occurs in pregnancy and typically resolves after childbirth.
However, having gestational diabetes also increases the risk of developing type 2 diabetes after pregnancy, so patients are often screened for type 2 diabetes at a later date.
According to the Centers for Disease Control and Prevention (CDC), 29.1 million people in the United States (U.S.) have diabetes.

Fast facts on diabetes

• Type 1 diabetes is often hereditary and unpreventable.
• Type 2 diabetes is much more common than type 1. For every person with type 1 diabetes, 20 will have type 2.
• Type 2 can be hereditary, but excess weight, a lack of exercise and an unhealthy diet increase
• At least a third of people in the U.S. will develop type 2 diabetes in their lifetime.
• Both types can lead to heart attack, stroke, nerve damage, kidney damage, and possible amputation of limbs.

Causes

People with type 1 diabetes will require supplemental insulin on an ongoing basis. People with type 2 will likely only need this for the later stages of the condition.

In type 1 diabetes, the immune system mistakenly attacks the insulin-producing pancreatic beta cells.
These cells are destroyed, reducing the body's ability to produce sufficient insulin and regulate blood glucose levels.
The body does not produce insulin, so the person needs supplemental insulin from the time they are diagnosed.
It often affects children and young adults, and it can start suddenly.
When type 2 diabetes starts, cells become resistant to the effects of insulin. In time, the body stops producing enough insulin, and the body can no longer use glucose effectively.
This means the cells cannot take up glucose, and glucose builds up in the blood.
This is called insulin resistance. If blood glucose is always high, the cells will be overexposed to insulin. They become less responsive or unresponsive to insulin.
Symptoms may take years to appear, and people can often use medications, diet, and exercise from in the early stages to reduce the risk or slow the disease.
People in the early stage of type 2 diabetes do not need supplemental insulin, but as the disease progresses, this may be necessary to control blood glucose control and to survive.
Type 2 often results from obesity and lifestyle and dietary factors, as well as medications and other issues.

Risk factors

Both types of diabetes may involve genetic factors.
In type 1, scientists have discovered a number of genes that are linked to the condition, developing the condition, but not everyone with these genetic factors develops it.
In type 2 diabetes, family history plays a key role.
Type 1 can emerge after a viral infection, such as mumps, or rubella cytomegalovirus.
Type 2 appears to be related to aging, an inactive lifestyle, diet, genetic influence, and obesity.
Both types 1 and type 2 appear to be more common in people with low levels of vitamin D, which is synthesized from sunlight.
Vitamin D supports immune function and insulin sensitivity, so those living at more northerly latitudes may face a higher risk of diabetes. Supplemental vitamin D may lower the risk of developing diabetes.

Diet

Diet has been linked to type 2 diabetes, but early diet may also have an impact on type 1.
Type 1 has sometimes been found to be more common in those who were introduced to cow's milk at an earlier stage. This suggests that breast-feeding for longer may reduce the risk. However, more research is needed.
Type 2 tends to be common in families where obesity is also a family trait. There may be a genetic link, or this may be because families have similar eating and exercise habits.
Diets high in simple sugars and low in fiber and vital nutrients have been linked to diabetes.

Symptoms

The consequences of persistently high levels of blood glucose can differ between types 1 and 2, but some symptoms and warning signs are common to both types.
The most serious complications involve kidney failure, eye problems and vision loss, neurological damage and increased risk of cardiovascular problems, including heart attack and stroke.
The table below shows some signs and symptoms of possible complications.

	Diabetes type 1		Diabetes type 2
Common physical attributes	BMI is mostly within the normal range or low.	BMI is in the overweight or obese range.
Onset	Rapid, often presenting acutely with ketoacidosis	Slow, sometimes taking years and often presenting without early symptoms
Warning signs	Extreme thirst and hunger Frequent urination Rapid weight loss Extreme weakness and fatigue Nausea, vomiting Irritability	Extreme thirst and hunger Frequent urination Rapid weight loss Extreme weakness and fatigue Nausea, vomiting Irritability Blurred vision Skin infections Sores that heal slowly Dry, itchy skin Pins and needles or numbness in feet
Complications	Diabetic coma or ketoacidosis High blood pressure Hypoglycemia, or low blood sugar Nephropathy, or kidney disease Blindness Heart attack Stroke Neuropathy Amputation Ulcers	Diabetic coma or ketoacidosis, due to high blood sugar High blood pressure Hypoglycemia, or low blood sugar Nephropathy Blindness Heart attack Stroke Neuropathy Amputation Ulcers

Diagnosis

A healthcare specialist will be able to test a patient for diabetes, even if type 2 diabetes shows no symptoms.

The onset of type 1 diabetes tends to be sudden. If symptoms are present, the person should see a doctor as soon as possible.
A person with prediabetes and the early stages of type 2 will have no symptoms.
If a routine blood test shows that blood sugar levels are high, action can be taken to delay or prevent diabetes and its complications.
Any of the following tests can be used for diagnosis of type 1 or type 2 diabetes, but they are not all recommended for diagnosing both types:

• A1C test, also called the hemoglobin A1c, HbA1c, or glycohemoglobin test
• Fasting plasma glucose (FPG) test

• Oral glucose tolerance test (OGTT)

Another blood test, the random plasma glucose (RPG) test, is sometimes used to diagnose diabetes during a regular health check.
If the RPG measures 200 micrograms per deciliter (d/L) or above, and the individual also shows symptoms, the person may receive a diagnosis of diabetes.
Blood test levels for diagnosis of diabetes and prediabetes are outlined below.

	A1C test (percent)	Fasting Plasma Glucose test (Milligrams per decilitre - mg/dL)	Oral Glucose Tolerance test (mg/dL)
Diabetes	6.5 or above	126 or above	200 or above
Prediabetes	5.7 to 6.4	100 to 125	140 to 199
Normal	Approximately 5	99 or below	139 or below

Treatment and prevention

There is no cure for diabetes, but medications can help manage it.
Insulin can regulate blood glucose, preventing hyperglycemic emergencies and protecting against some long-term complications.
Below is a list of the current methods known to treat and prevent diabetes type 1 and type 2.

	Diabetes type 1	Diabetes type 2
Cure	None. Some researchers are currently looking at the potential benefits of a combination of immunosuppressant drugs, and drugs that increase gastrin production to encourage pancreatic regeneration, that may allow people with type 1 diabetes to live insulin-free.	There is no cure for type 2 diabetes, although gastric bypass surgery, lifestyle, and medication treatment can result in remission. An active lifestyle, healthy loss of weight, and diet control is advised.
Prevention	No known way to prevent the autoimmune attack on pancreatic, insulin-producing cells.	Preventable and can be delayed with a healthy diet and active lifestyle.
Treatment	Injections of insulin Rarely, oral medications Dietary modifications Physical activity Regular check-up of blood sugar levels and A1C Controlling blood pressure Treating high cholesterol levels	Using diabetes medicines Sometimes insulin injections Healthy food choices Exercise Self-Monitoring of Blood Glucose (SMBG) Controlling blood pressure Treating high cholesterol levels