Understanding Type 1 Diabetes
Successful diabetes management isn’t just about insulin or treatment — it’s also about knowledge.
Understanding the basic concepts and processes can help you make more confident and calmer decisions in everyday life.
This content is not medical advice. Always consult your healthcare or diabetes care team before making any changes to your diabetes treatment or daily management.
What is Type 1 Diabetes?
Type 1 diabetes is an autoimmune disease in which the immune system mistakenly destroys the pancreas cells that produce insulin. Without insulin, the body cannot use glucose from the blood for energy, and high blood sugar levels can become life-threatening. People with type 1 diabetes must take insulin every day through injections or an insulin pump, because their body cannot produce it on its own.
According to the World Health Organization, around 9 million people worldwide live with type 1 diabetes (2017 data). The most recent estimates from 2021 indicate that approximately 8.4 million people are affected, with about 500,000 new cases reported that year. Of those affected, 18% are children and adolescents.
In Europe, according to IDF data, about 295,000 children and young people live with type 1 diabetes, and more than 31,000 new cases are diagnosed each year in this age group. Europe has the highest number of young people with this condition compared to other regions.
It’s important to emphasize that type 1 diabetes is not caused by diet, obesity, or lifestyle. Its cause lies in a combination of genetic and environmental factors. It cannot be prevented or cured — but it can be successfully managed with insulin and proper care.
Type 1 diabetes is not the same as type 2 diabetes. While type 1 is an autoimmune condition and most commonly diagnosed in children and young adults, type 2 is more common in adults and is often linked to insulin resistance, excess weight, and lifestyle factors. Type 2 diabetes can sometimes be managed with healthy eating, physical activity, and oral medications, while people with type 1 diabetes will always require insulin.
What Are the Symptoms of Type 1 Diabetes?
Type 1 diabetes often appears suddenly, and symptoms become noticeable when most of the insulin-producing cells (beta cells) in the pancreas are already destroyed. Once the body can no longer regulate blood sugar levels, a set of recognizable signs begins to appear and it’s important to catch them early.
The most common symptoms include:
Increased thirst, even when drinking plenty of fluids
Frequent urination, especially at night
Increased appetite, often combined with unexplained weight loss
Fatigue and weakness without a clear cause
Blurred vision
Dry mouth and signs of dehydration
Sweet or fruity-smelling breath (especially in cases of ketoacidosis)
Nausea and vomiting
Confusion, drowsiness, and in more serious cases, fainting
Rapid and deep breathing (also known as Kussmaul breathing)
Fungal infections in girls, including infants and toddlers
Bedwetting, especially in children who were previously dry at night
Presence of sugar and ketones in the urine (usually confirmed by testing)
Symptoms can develop quickly — within days or weeks. That’s why it’s essential to act promptly if several of these signs appear at the same time, especially in children and young peopl
Although the symptoms appear suddenly, the actual development of the disease takes much longer.
In the background, the immune system slowly destroys the insulin-producing cells in the pancreas over months or even years, until the body can no longer regulate blood sugar and that’s when the symptoms suddenly appear.
If you suspect that you, your child, or another close person has diabetes, contact your doctor immediately.
Untreated type 1 diabetes can lead to a serious condition called diabetic ketoacidosis, which can be life-threatening.
What Causes Type 1 Diabetes?
Type 1 diabetes doesn’t develop overnight. While symptoms often appear suddenly, the disease itself progresses gradually over many years. Research including studies from the Joslin Diabetes Center has shown that changes in the body can begin up to nine years before the first symptoms appear.
The development of type 1 diabetes can be understood in several stages:
Genetic predisposition
A person may inherit genes that increase the risk of autoimmune activity. However, this doesn’t mean they will definitely develop the disease. Many people with these genes never develop diabetes.Environmental trigger
An infection, stress, or another environmental factor may trigger the immune system to begin reacting against the body’s own cells.Onset of autoimmunity
The immune system starts attacking the beta cells in the pancreas that produce insulin. This phase is silent — there are no visible symptoms — but diabetes-related antibodies can be detected in the blood.Gradual beta-cell destruction
Over time, the number of insulin-producing cells declines. The body struggles more and more to regulate blood sugar. There may still be no clear symptoms, but blood glucose levels may start to rise.Onset of type 1 diabetes symptoms
When more than 90% of beta cells are destroyed, the body can no longer regulate blood sugar on its own. This is when classic symptoms appear: excessive thirst, frequent urination, fatigue, weight loss, and others.
Type 1 Diabetes and Life Inside the Pancreas
Although type 1 diabetes is often viewed as a complete shutdown of insulin production, new insights tell a more nuanced story. In some individuals who have lived with the disease for many years, small but measurable amounts of C-peptide — a byproduct released along with insulin can still be detected. This suggests that some beta cells may still be functioning, at least partially.
This raises an important question: is the body still trying to generate new islet cells, even under continuous autoimmune attack?
While the answers are not yet definitive, studies suggest that preserved or regenerated pancreatic activity may help reduce the risk of complications, improve blood sugar stability, and contribute to a better quality of life. These findings are reshaping our understanding of type 1 diabetes and encouraging new research into therapies that not only replace insulin but also aim to protect what the body still has.
Most people with type 1 diabetes have a genetic predisposition, but the disease usually develops only after one or more environmental triggers.
People with type 1 diabetes have a genetic predisposition, but the disease usually develops only after one or more environmental triggers.
This fact is supported by studies on identical twins: when one twin develops T1D, the other does so in only 13–33% of cases, which strongly suggests the role of environmental factors.
One of the most studied environmental triggers is the Coxsackie B virus, a type of enterovirus. Research including data from the Finnish DIPP study has shown that infection with this virus significantly increases the risk of developing diabetes-related autoantibodies, especially insulin autoantibodies (IAA). (link.springer.com)
The appearance of autoantibodies such as islet cell antibodies, GAD antibodies, and ICA-512 can be detected months or even years before any clinical signs of the disease, revealing the silent beginning of type 1 diabetes.
Risk Factors for Type 1 Diabetes
People with type 1 diabetes typically have a genetic predisposition, but the disease usually develops only when multiple factors come together. Studies on identical twins show that if one twin has T1D, the other develops it only in 30–50% of cases — clearly indicating that genetics alone is not enough (Cell Genomics, 2025).
If one parent has type 1 diabetes, the child’s risk is approximately:
6–7% if the father is affected,
1.5–2.5% if the mother is affected.
If both parents have type 1 diabetes, the risk is significantly higher.
Risk can be further refined through HLA typing on chromosome 6. Some gene patterns increase risk, while others are considered protective.
As for environmental factors, studies like TEDDY and DIPP suggest that viral infections, especially Coxsackie B virus, may act as triggers that initiate the autoimmune process in genetically susceptible individuals.
Once triggered, the immune system produces autoantibodies, which can be detected months or even years before symptoms appear.
Summary of Key Findings:
Genetic predisposition alone is not enough.
Risk is higher in families with a history of type 1 diabetes, especially from the father.
Identical twins don’t always both develop T1D — highlighting the role of the environment.
Autoantibodies can be detected well before symptoms appear.
Viral infections, especially Coxsackie B, are considered potential triggers.
HLA typing helps estimate individual genetic risk.
Why Does Insulin Have to Be Injected?
Insulin is a protein. If taken by mouth, it would be broken down by the digestive system — just like the proteins we eat and wouldn’t reach the bloodstream in a usable form. That’s why insulin must be delivered through injections or pumps, directly into the body.
There is one exception: a form of inhalable insulin called Afrezza. It’s a fast-acting insulin that is inhaled before meals using a special device. However, it’s not suitable for everyone and doesn’t replace long-acting (basal) insulin. It is not recommended for people with asthma, lung disease, or for those who smoke.
In most cases, injectable insulin remains the safest and most effective way to manage type 1 diabetes.
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