Type 1 diabetes

What is the definition of type 1 diabetes or juvenile diabetes?

Type 1 diabetes is an autoimmune disease in which the immune system attacks the beta cells of the islets of Langerhans in the pancreas. These cells are essential for the production of insulin, which regulates the level of glucose (or blood sugar) by facilitating its entry into cells to be used as an energy source. In the absence of insulin, glucose accumulates in the blood, leading to hyperglycemia. This disease is called juvenile diabetes because it is often diagnosed in children and adolescents, although it can appear at any age.

According to the High Authority of Health, the diagnosis of diabetes type 1 is usually made before the age of 45, with an immediate need for insulin treatment. Understanding the origin of diabetes type 1 is essential for developing effective prevention and management strategies.

At what age does type 1 diabetes start?

Type 1 diabetes can occur at any age, but it is most often diagnosed in children, adolescents, and young adults. In France, the incidence of diabetes type 1 is increasing by 3 to 4% per year for about 20 years, with a noticeable increase in children under 5 years old. In some infants, the onset can occur in the first months of life, although this is rare. Half of the cases occur before the age of 20. However, it is not uncommon to diagnose this disease in adult patients, even after 40 years, although this is less common. In addition, diagnosing type 1 diabetes in adults requires special attention, as symptoms may be less obvious.

What are the risk factors for insulin-dependent diabetes?

Several factors can increase the risk of developing insulin-dependent diabetes:

• Genetic predisposition: Patients with a parent suffering from type 1 diabetes have an increased risk of developing the condition.
• Environmental exposures: Factors such as certain viral infections (for example, enterovirus infections), exposure to toxins, or changes in the gut flora could influence the onset of a glycemic disorder.
• Type of breastfeeding: Studies suggest that the type of breastfeeding during the first months of life could play a role, although the mechanisms are not clearly established.
• Immunological factors: The presence of auto-antibodies may indicate a predisposition.

Furthermore, the incidence of diabetes type 1 varies by region, suggesting that local environmental factors play a role. Environmental changes, such as shifts in diet or exposure to new infectious agents, could also contribute to its increasing prevalence.

What are the causes of type 1 diabetes?

Type 1 diabetes results from a complex interaction between genetic and environmental factors:

• Autoimmune reaction: The immune system, normally responsible for defending the body against pathogens, turns against the beta cells of the pancreas, gradually destroying them. This immune attack leads to a decrease, then a total absence of insulin production.
• Genetic factors: Variations in certain genes of the HLA (Human Leukocyte Antigen) system increase susceptibility to the disease.
• Environmental factors: Viral infections (such as enteroviruses), exposure to environmental or food toxins, and changes in the intestinal flora are considered as potential triggers.

The exact mechanisms of the origin of diabetes type 1 are still poorly understood, and research continues to seek new leads to explain this disease. It is important to note that the mere presence of genetic predispositions does not systematically lead to type 1 diabetes; they increase the risk, but other factors are necessary to trigger the disease.

Is there a heredity in type 1 diabetes?

Yes, there is a hereditary component. A patient with a first-degree relative (father, mother, brother, or sister) with this disease has an increased risk of developing it. However, heredity alone does not explain the occurrence of type 1 diabetes. The disease results from an interaction between genetic predispositions to susceptibility and environmental risks. It is also common for associated autoimmune diseases, such as celiac disease or autoimmune thyroiditis, to be present in the same family.

What are the symptoms of type 1 diabetes?

The signs usually appear quickly and may include:

• Polydipsia : a intense and constant thirst.
• Polyuria: an increase in frequency and volume of urination, which can lead to bedwetting in children.
• Rapid weight loss despite a good appetite.
• Extreme fatigue and irritability.
• Blurred vision due to hyperglycemia.
• Recurrent infections such as skin or urinary infections.
• Nausea and vomiting in case of complications.

In some cases of diabetes type 1, the signs can be confused with other diseases, delaying diagnosis. These symptoms are the result of the cells’ inability to use glucose to produce energy, due to a lack of insulin.

What are the signs of diabetes decompensation?

The diabetic decompensation occurs when diabetes is undiagnosed or inadequately treated. The signs include:

• Diabetic ketoacidosis: accumulation of ketone bodies in the blood due to the use of fats as an energy source. This can result in fruity-smelling breath, abdominal pain, nausea, and vomiting.
• Severe dehydration due to polyuria.
• Consciousness disorders ranging from drowsiness to coma in severe cases.
• Kussmaul breathing: a deep and labored breathing to compensate for metabolic acidosis.

This situation can occur years after the onset of the disease if it is not properly managed. The successive measurements of the blood sugar level are essential for preventing this complication. Decompensation is a medical emergency requiring rapid intervention to avoid serious complications.

What are the complications of type 1 diabetes?

Insulin dependence

Patients with type 1 diabetes are insulin-dependent, meaning they must receive daily exogenous insulin to survive. Insulin is administered by multiple injections or through an insulin pump. Without this treatment, hyperglycemia persists and patients risk a potentially fatal diabetic ketoacidosis. The insulin pump allows continuous insulin administration, improving glycemic control. Although insulin therapy is essential, it can lead to hypoglycemia in case of overdose or measurement error. Close monitoring of blood glucose levels is therefore crucial.

The consequences on the organs of the disease

Poorly controlled blood sugar over the long term can lead to microvascular complications and macrovascular complications:

• Diabetic retinopathy: damage to the blood vessels of the retina that can lead to blindness.
• Diabetic nephropathy: a kidney condition that can progress to end-stage renal disease.
• Diabetic neuropathy: damage to the peripheral nerves causing pain, numbness, or digestive problems.
• Cardiovascular diseases: increased risk of myocardial infarction, stroke, and peripheral arterial disease.
• Diabetic foot: ulcerations and infections of the foot that can lead to amputations.

These complications can appear several years after the onset of diabetes, especially if the blood glucose is not properly controlled. It is therefore essential to monitor blood glucose in the long term and to adopt a healthy lifestyle including regular physical activity.

Hypoglycemia

Hypoglycemia occurs when the level of blood sugar drops below normal values (< 0.70 g/L). It can be caused by an excessive amount of insulin, intense physical exercise without adjusting the insulin dose, or insufficient food intake. Symptoms include:

• Tremors, sweating, palpitations.
• Dizziness, vision problems.
• Confusion, behavioral disorders.
• Loss of consciousness in severe cases.

Prevention involves regular measurement of blood glucose levels and appropriate adjustment of treatment. Good management of physical exercise and diet is essential to avoid these serious complications.

How is type 1 diabetes diagnosed?

Blood glucose disorders

The diagnosis is based on successive blood sugar tests:

• A fasting blood sugar ≥ 1.26 g/L (7.0 mmol/L) on two consecutive measures .
• An random blood glucose level ≥ 2.00 g/L (11.1 mmol/L) associated with suggestive symptoms.
• A level of glycated hemoglobin (HbA1c) ≥ 6.5 %.

These values confirm a significant hyperglycemia. Day after day, the rate of blood glucose can fluctuate significantly, making regular measurements essential for a reliable diagnosis. Early detection is crucial for initiating treatment appropriately.

The detection of antibodies

La presence of auto-antibodies directed against the beta cells of the pancreas is characteristic of type 1 diabetes:

• Auto-antibodies against GAD (glutamate decarboxylase).
• Autoantibodies against IA2 (Langerhans islets).
• Auto-antibodies against insulin.

The detection of these autoantibodies helps differentiate type 1 diabetes from type 2 diabetes. The presence of specific autoantibodies demonstrates the attack of the immune system against the pancreatic cells, particularly the Islets of Langerhans.

Quels traitements sont disponibles ?

Insulin therapy with pen

Insulin therapy is the cornerstone of treatment for type 1 diabetes. It involves subcutaneous injections of insulin using injection pens:

• Insulins rapid-acting or ultra-fast-acting administered before the meals to control the rise of the blood glucose postprandial.
• Long-acting insulins to maintain stable basal blood glucose levels between meals and overnight.

The administration schedule is individualized based on the needs of the patient, their lifestyle, and their dietary habits.

The insulin pump

The insulin pump is a portable device the size of a phone that delivers insulin continuously. It allows a fine-tuning of insulin doses based on the blood sugar levels measured by the patient. The benefits include:

• A better quality of life with fewer daily injections.
• A more precise management of glycemic variations.
• A reduction in the risk of hypoglycemia.

The transplantation of Langerhans islets of pancreatic cells

For patients whose diabetes is difficult to manage, a Langerhans islets transplant may be considered. This procedure involves transplanting insulin-producing cells into the patient’s liver. The challenges associated with this technique include:

• The need for immunosuppressive treatments to prevent graft rejection.
• Limited availability of pancreatic islets.
• Variable outcomes in terms of sustainable restoration of insulin production.

Thanks to advances in science, innovative grafting techniques are being developed to improve the efficiency of this treatment. Research is also continuing to explore other therapeutic avenues to provide new options for patients.

How to live with type 1 diabetes on a daily basis?

Living with type 1 diabetes requires rigorous self-management:

• Glucose monitoring : Regular measurement of blood glucose levels using glucose meters or continuous monitoring devices.
• Insulin dose adjustment : Dose adjustments based on food intake, physical exercise and blood glucose results.
• Balanced diet: Adoption of a suitable diet, distributing carbohydrates regularly to avoid glycemic spikes.
• Physical activity : Regular practice of physical exercise taking into account the effect on blood sugar and adapting the treatment accordingly.
• Therapeutic education: Participation in education programs to better understand the disease, treatment, and self-management techniques.
• Regular medical follow-up: Regular consultations with a multidisciplinary medical team to monitor glycemic balance and screen for potential complications.

The goal is to keep blood sugar as close as possible to normal values to prevent serious complications and improve quality of life.

What are the current research avenues?

Research on type 1 diabetes is very active, with several promising avenues:

• Cell therapy : Development of techniques to regenerate the beta cells or to protect them from autoimmune destruction.
• Artificial pancreas : Combination of an insulin pump and a glucose sensor to automate the management of insulin.
• Immunotherapy : Approaches aimed at modulating the immune system to stop or slow the destruction of beta cells.
• Vaccines: Research on vaccines to prevent the onset of type 1 diabetes in high-risk individuals.
• Genetics: Studies on genetic factors to understand the mechanisms of the disease and identify new therapeutic targets.
• Gut microbiota: Exploring the role of the intestinal flora in the development of type 1 diabetes and possibilities for modulating the microbiota to prevent or treat the disease.

These studies offer hope for new strategies to prevent, treat, and potentially cure type 1 diabetes.