Introduction
Diabetes is a chronic health condition that affects the way the body uses food for energy. Food is mostly converted to sugar that is carried in the blood stream and delivered to the body’s cells. Insulin is a hormone produced by the pancreas that helps sugar enter the cells in your body where it can be used for energy. Without insulin, the sugar in the blood would build up in the bloodstream. Having high blood sugar levels for long periods can damage the body and result in diabetes complications.
The two most common forms of diabetes are type 1 diabetes and type 2 diabetes. Type 1 diabetes is an autoimmune condition that results in deficiency of insulin due to damage of the insulin-producing cells in the body. Type 2 diabetes is a more complex metabolic condition in which the body is “resistant” to insulin, and is also unable to increase insulin production to the level necessary to overcome this resistance.
Diabetes has become more prevalent in the general population and data shows an increase in the incidence of diabetes in both adults and children. Early recognition of symptoms allows for a prompt diagnosis, initiation of treatment, and a decrease in potential complications.
Are children with Down syndrome at increased risk of diabetes?
Overall, diabetes is four to six times more common in children and adolescents with Down syndrome than in the general pediatric population. Most cases of diabetes in children with Down syndrome are type 1 diabetes.
Type 1 diabetes is one of a number of autoimmune conditions for which children with Down syndrome are at increased risk. They are also more likely to be diagnosed at an earlier age, with 17-22% diagnosed before the age of 2 years compared to only 4-7% of typically developing children. There are a number of genes on chromosome 21 that are important to the function of the immune system and that have been associated with increased risk for type 1 diabetes including the UBASH3A, DYRK1A, and AIRE genes. It seems likely that having three copies of these genes could interfere with gene expression and function, but their role in the increased risk of type 1 diabetes in children with Down syndrome is still under investigation.
Type 2 diabetes is also more common and occurs at a younger age in people with Down syndrome than in the general population. This may be related to the higher prevalence of overweight in people with Down syndrome, as well as decreased muscle tone, reduced activity levels, and lower energy needs. Overweight status along with larger abdominal fat stores contribute to insulin resistance and increase risk of metabolic syndrome and type 2 diabetes.
What are the symptoms of diabetes?
High blood sugar levels can cause a number of symptoms:
- Increased urination
- Increased thirst
- Weight loss
- Increased appetite
- Low energy, fatigue
- Blurry vision
- Dry skin
- Fungal infections
How is diabetes diagnosed?
There are several different tests your doctor can order if you suspect that your child may have diabetes.
Two tests can be drawn at any time of day without fasting: the first is a blood test called a “hemoglobin A1c” level; this reflects the average blood sugar level over the prior two to three months. A hemoglobin A1c level of 6.5% or higher is consistent with a diagnosis of diabetes. The second is a random blood sugar level. A blood sugar level of 200 mg/dl or higher is consistent with a diagnosis of diabetes.
Although less convenient, a fasting blood sugar level (which measures the blood sugar after an overnight fast) can also be used to screen for diabetes. A fasting blood sugar level of 126 mg/dl or higher is also consistent with a diagnosis of diabetes.
If these tests are normal but there is still a concern, the doctor may order a “glucose tolerance test” that can diagnose diabetes in its early stages. This measures the blood sugar before and after drinking a sugary liquid. A blood sugar level of 200 mg/dl or higher at the two-hour mark is consistent with a diagnosis of diabetes.
If your doctor wants to confirm the type of diabetes, blood may also be tested for autoantibodies (markers of an autoimmune process involving the insulin producing cells) that are often present in type 1 diabetes but not in type 2 diabetes.
How is diabetes treated?
People with type 1 diabetes will need to take insulin every day to stay healthy because they have an insulin deficiency. Insulin needs to be taken as an injection because the stomach would digest it before it was absorbed into the bloodstream if taken as a pill. Frequent blood sugar monitoring is also a critical part of management since insulin doses need to be adjusted frequently. Advances in diabetes technology over the past five years have allowed for improved control with a decrease in burden (see below).
People with type 2 diabetes may need insulin but often can manage blood sugar levels without insulin using other types of medications and lifestyle. Improving the way the body responds to insulin is a focus in type 2 diabetes treatment. Weight loss, exercise, and dietary choices high in fiber and low in simple sugars can improve insulin sensitivity.
Healthy food choices and daily physical exercise are important in managing all forms of diabetes and maintaining heart health. A multidisciplinary team at a diabetes center can help you and your family get the education and support needed to manage diabetes effectively.
Insulin delivery
Insulin can be given in half-unit increments through a syringe or an insulin pen. Pens are able to deliver doses more accurately and many children find them more comfortable to use than syringes.
Insulin pumps are increasingly used as a standard of care and offer a number of benefits, including more precise dosing, a need for less frequent injections, and the integration of insulin dose calculators. Insulin is continuously infused through a catheter inserted into the fatty layer under the skin for up to three days and can also be given as “boluses” when eating or to give a correction dose for a high blood sugar level.
Blood sugar monitoring
Blood sugar levels can be checked intermittently using a drop of blood from a fingerstick and a blood glucose meter. It is also possible to use a continuous glucose monitor (CGM) that continuously measures glucose levels under the skin. This allows for identification of patterns and adjustments in regimens that can improve diabetes control.
Hybrid Closed Loop (HCL) systems
Hybrid closed-loop systems allow your insulin pump to communicate with your continuous glucose monitor (CGM). It continuously monitors blood glucose levels, calculates the amount of insulin required using an algorithm that has been added to the system, and then automatically adjusts your background insulin based on your blood sugar readings. Some systems also give boluses of insulin to correct high blood sugar levels.
Summary
Keeping blood sugar levels in the target range decreases the chance of developing diabetes complications in the future. Steady blood sugar levels can also help children feel their best every day, improving their energy levels and sleep patterns. Children with Down syndrome may have additional challenges adjusting to a diabetes regimen, so make sure to ask your diabetes team about resources that might help your child, such as working with a child life specialist or psychologist.
Mary Pat Gallagher, MD
Director, Robert I. Grossman, MD and Elisabeth J. Cohen, MD Pediatric Diabetes Center
Hassenfeld Children’s Hospital at NYU Langone
Department of Pediatrics