Type 1 diabetes is a condition that leads to high blood glucose (sugar). Although lots of studies have looked into this condition, the exact cause of type 1 diabetes remains unknown. However, researchers have linked a number of factors with developing type 1 diabetes.

In this article, we explain the factors that may cause type 1 diabetes.

How Does Type 1 Diabetes Develop?

Type 1 diabetes is an autoimmune disease that results from an overactive immune system, which normally protects the body from foreign invaders like bacteria and viruses. In people with type 1 diabetes, the immune system is triggered to make autoantibodies (specialized immune proteins) that attack the pancreas’s insulin-producing cells, called beta cells. Researchers are still learning about what prompts the immune system to attack the pancreas.

Your pancreas makes insulin, a hormone that allows glucose to enter the cells and be converted into energy. As your immune system destroys more and more beta cells, your pancreas can no longer produce insulin.

Without insulin, blood glucose levels can become dangerously high and cause symptoms such as:

• Frequent urination (peeing more often than usual)
• Increased thirst
• Greater hunger
• Weight loss
• Blurred vision
• Mood changes
• Fatigue

Over time, high blood glucose levels can damage different organs and cause long-term health problems such as:

• Heart and blood vessel problems
• Nerve damage
• Kidney disease
• Eye problems
• Skin problems
• Complications during pregnancy

What Are the Risk Factors for Type 1 Diabetes?

Although researchers don’t know why type 1 diabetes develops in some people, children and adolescents are more likely to be diagnosed. In fact, type 1 diabetes used to be referred to as juvenile diabetes. Type 1 diabetes is mostly commonly diagnosed between ages 4 and 7 years and between 10 and 14.

Other groups of people who may be at higher risk of type 1 diabetes include those who:

• Have a parent or sibling with type 1 diabetes
• Live farther from the equator
• Have certain genes

Genetic Factors

Genetic factors are risk factors passed on from parents to their children, such as gene changes linked with a higher risk of type 1 diabetes. The main genes involved in developing type 1 diabetes are called human leukocyte antigen (HLA) genes, which help the immune system distinguish between its own cells and foreign invaders.

Everyone who develops type 1 diabetes has genetic risk factors for the condition. Having a parent or sibling with type 1 diabetes makes you 15 times as likely to develop it compared to someone who doesn’t have a first-degree relative with the condition.

Researchers have found that the risk of developing type 1 diabetes is between 1 percent and 4 percent for a person whose mother has type 1 diabetes and between 3 percent and 8 percent for someone with a father with type 1 diabetes. If both parents have type 1 diabetes, their child’s risk can be as high as 30 percent.

However, not everyone with genetic risk factors will develop type 1 diabetes. For example, sometimes one identical twin develops type 1 diabetes and the other doesn’t, even though they have the same genes.

Environmental Factors

Because people with the same genetic risk factors don’t always develop type 1 diabetes at the same rate, researchers think other factors in the environment play a role. Findings related to how environmental factors’ involvement in type 1 diabetes aren’t conclusive, and studies in this area continue.

Viral Infections

Some types of viral infections may increase your risk of developing type 1 diabetes. For example, researchers think certain viruses might trigger the immune system to attack the pancreas.

Infection with human enteroviruses has the strongest association with type 1 diabetes. Human enteroviruses cause a wide range of diseases, including polio and the common cold.

Severe viral respiratory (lung) infections are also linked with developing type 1 diabetes. This may suggest an explanation for why it’s more common to be diagnosed with type 1 diabetes in cold winter months — that’s when you’re more likely to catch one of these illnesses.

Vitamin D

Vitamin D is a nutrient important for overall health, including to support your immune system. Researchers studying vitamin D’s effect on the development of type 1 diabetes found that supplementation in the first year of life may reduce the risk. Additionally, vitamin D deficiency is common in people newly diagnosed with type 1 diabetes.

Diet

Researchers are investigating whether the food we eat — especially as infants — may affect the risk of developing type 1 diabetes. Although the research has yet to provide a definite link, foods and drinks being investigated for the possibility of developing type 1 diabetes include:

• Gluten
• Cereals
• Root vegetables
• Cow’s milk
• Foods and drinks containing nitrates

On the other hand, breastfeeding and eating foods containing omega-3 fatty acids, such as walnuts and leafy vegetables, may reduce the risk of developing type 1 diabetes.

Gut Microbiome

Your gut microbiome is made of the helpful bacteria that help digest food and can influence your overall health. Everyone has a unique microbiome made of tiny organisms that help break down sugars and make certain vitamins. Several bacteria work together to keep you healthy.

Some studies show that people diagnosed with type 1 diabetes have fewer types of certain bacteria compared to people without type 1 diabetes. Several factors can affect your gut microbiome, including:

• Diet early in life
• Birth by cesarean section
• Antibiotic use

Lifestyle Factors

Thus far, no research proves that diet or lifestyle factors affect the risk of type 1 diabetes. However, some evidence suggests that certain foods may speed its progression in at-risk children.

A 2008 study focused on children at risk of developing type 1 diabetes and found that eating foods with a higher dietary glycemic index (foods that quickly raise blood sugar levels) wasn’t associated with developing autoantibodies. However, eating those types of foods was linked with progressing faster to type 1 diabetes for people in the early stages of the disease.

Unlike type 1 diabetes, type 2 diabetes may stem from diet and lifestyle factors. People with this type may have high blood sugar because their body doesn’t respond to insulin as well as it should, which is known as insulin resistance. The pancreas tries to secrete more insulin but eventually can’t keep up with the body’s needs.

Can You Determine Your Risk of Type 1 Diabetes?

If you’re worried about the risk of type 1 diabetes for yourself or your child, talk to your health care team about a diabetes risk screening test. Not everyone needs to be tested for type 1 diabetes.

You may qualify if you have a family history — a parent, sibling, or child diagnosed with type 1 diabetes. However, about 85 percent of people diagnosed with type 1 diabetes don’t have a family member with type 1 diabetes. A diabetes risk screening test will look for autoantibodies that target the pancreas. If you have two or more types of diabetes-related autoantibodies, you have a high risk of developing type 1 diabetes.

Can Type 1 Diabetes Be Prevented?

A healthy lifestyle won’t help you avoid type 1 diabetes in the same way it may help ward off type 2 diabetes. Unfortunately, nothing can totally prevent type 1 diabetes. However, early detection and treatment of type 1 diabetes may slow progression and help prevent life-threatening complications of diabetes.

Talk With Others Who Understand

On myT1Dteam, the social network for people living with type 1 diabetes and their loved ones, members come together to ask questions, give advice, and share their stories with those who understand life with type 1 diabetes.

Are you or your child living with type 1 diabetes? Do you have a family history or other risk factors for this condition? Share your experience in a comment below, or start a conversation on your Activities page.