Frequently Asked Questions

Questions about the study

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What is Type 1 diabetes?

Diabetes mellitus is a general name for a group of diseases characterized by high blood sugar (glucose) levels. This group includes Type1 and Type 2 diabetes, gestational diabetes, and diabetes caused by other conditions. Type 1 diabetes, also known as juvenile-onset or insulin-dependent diabetes, is most commonly diagnosed during childhood or adolescence, although it is also diagnosed in adults. In Type 1 diabetes, the pancreas fails to produce enough insulin for the body to maintain normal blood sugar levels. In our study, we recruited persons who were diagnosed with Type 1 diabetes before the age of 30.

What is an ‘observational’ study?

In an observational (or health tracking) study, the researchers do not intervene or interfere in a study participant’s care. Rather, the study participant’s health is observed by asking questions and inviting participation in a clinical examination. This is different from a clinical trial, in which people are asked to take certain treatments and are then followed for outcomes to those treatments.

What is a ‘longitudinal’ study?

In a longitudinal study, participants are followed over time. This is important for accurately describing the patterns and trends of a disease. For example, a person’s health and risk for complications may change as he/she ages and as the length of time spent with diabetes increases. New types of insulin and other new therapies may influence health and may affect how a person treats his or her diabetes. It’s especially important to describe health with these changes in mind.

What is diabetic retinopathy?

Retinopathy literally means “damage to the retina.” The retina is the sensory membrane that lines the eye. It functions as the immediate instrument of vision by receiving images formed by the lens and converting them into signals which reach the brain by way of the optic nerve. Diabetic retinopathy occurs when the blood vessels in the retina swell and leak blood, which causes damage to the retina.

There are two forms of diabetic retinopathy: non-proliferative (background) retinopathy and proliferative retinopathy. Non-proliferative diabetic retinopathy occurs when small blood vessels in the retina break and leak. Small pouches filled with the leaked blood form. People experiencing non-proliferative diabetic retinopathy may notice blurred or distorted vision from blood that is obscuring the light-sensitive retina. Proliferative diabetic retinopathy is characterized by abnormal growth of new blood vessels within the retina. New growth can lead to scarring or retinal detachment (the retina detaches from the surrounding tissue) which can lead to vision loss. The new blood vessels can also grow or bleed into the vitreous humor, the transparent gel filling the eyeball in front of the retina. Proliferative diabetic retinopathy is much more serious than non-proliferative diabetic retinopathy, and can lead to total blindness if left un-treated.

Diabetic retinopathy is the most common eye disease associated with diabetes, and is the leading cause of blindness in American adults. Nearly half of all people with diabetes will develop some degree of diabetic retinopathy. Tight control of glucose levels has been shown to have a tremendous impact on reducing the risk for diabetic retinopathy. In 1993 the Diabetes Control and Complications Trial showed that tight glycemic control reduces risk by 76%. For people who already had diabetic retinopathy, tight control slowed progression by 50%.

What is diabetic nephropathy?

Nephropathy is any disease of the kidney. Diabetic nephropathy is a complication of diabetes characterized by deteriorating function of the kidney, from normal function to end-stage renal disease (ESRD). Diabetic nephropathy causes progressive damage to the small filtering units of the kidney, called glomeruli. This damage leads to the excretion (or leaking) of albumin (protein) into the urine. The earliest clinical evidence of diabetic nephropathy is the appearance of low, but abnormal, levels of albumin in the urine. This condition is called microalbuminuria, when the protein excretion rate is 20-200 mcg/min. Albumin levels in the urine can be temporarily elevated by exercise, a urinary tract infection, heart disease, fever, and hyperglycemia. Because of these possible causes of increased albumin excretion, microalbuminuria is usually not clinically diagnosed unless elevated levels are detected in 2 of 3 samples.

What is diabetic neuropathy?

Diabetic neuropathy is a nerve disorder caused by diabetes. The damage to the nerves reduces the ability of the nerves to carry messages to the brain and other parts of the body. Symptoms can vary, but numbness and tingling are usually the first signs of diabetic neuropathy. Some people experience no symptoms, others have severe pain or insensitivity to pain, and others experience some combination of each.

There are two major types of diabetic neuropathy: diffuse and focal. Diffuse neuropathy affects larger areas and the damage is not focused in a single place. Diffuse diabetic neuropathy can either effect peripheral body parts, such as the legs, feet, hands, and arms, or it can affect autonomic parts of the body, including the heart, digestive system, sexual organs, urinary tract, and sweat glands. Common symptoms of diffuse neuropathy include numbness, tingling, sharp pain or cramps, extreme sensitivity to touch, and loss of balance and coordination. Focal neuropathy appears suddenly and affects specific nerves, most often in the torso, legs, or head. This kind of neuropathy is unpredictable and occurs most frequently in older people with mild diabetes. Focal neuropathy can be quite painful, but it usually improves by itself over a period of weeks and leaves no long-term damage.

Questions about blood sugar control

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What is the hemoglobin A1c test?

The hemoglobin A1c (HbA1c) test is a simple lab test that indicates the amount of sugar (glucose) that has been in a person’s blood over the last 3 months, giving an idea of a person’s blood sugar control. Glucose in the bloodstream can become attached to the hemoglobin (the part of the cell that carries oxygen) in red blood cells. This process is called glycosylation. Once the glucose molecule is attached, it stays there for the life of the red blood cell, which is about 120 days. As blood sugar levels increase, more glucose molecules attach to the red blood cells. The HbA1c test measures the amount of glucose attached to the hemoglobin in the red blood cells. Test results are given in percentages.

What is an insulin pump?

An insulin pump is a microcomputer, about the size of a beeper, that delivers insulin into the body. Insulin pumps mimic the behavior of a pancreas in someone who does not have diabetes by releasing small amounts of insulin continuously throughout the day (called the basal rate) and larger amounts of insulin when the pump user eats a meal (called the bolus dose). Insulin is delivered into the body through thin tubing that attaches to the pump at one end and is inserted into the abdomen with a special needle (about the size of an insulin needle) at the other end. Once the tubing is in place, the needle is removed and clear tape is placed over the insertion site. Insulin is then delivered directly into the tissue of the abdomen.

What is islet cell transplantation?

The Islets of Langerhorn are clusters of cells in the pancreas that contain the body’s insulin-producing beta cells. There are more than one million islets in a pancreas, but they comprise only 1-2% of the organ’s mass. Type 1 diabetes occurs when these cells can no longer produce the amount of insulin that is necessary. Islet cell transplantation is performed without an incision, and the islets are injected into the portal vein, which leads directly to the liver.

There are several human islet transplant trials underway at centers around the world. Researchers are working on creating sources of islet cells other than the human pancreas, and on developing ways to regenerate a person’s own islets.

Islet cell transplantation is still considered an experimental procedure. There are several difficulties that scientists are working to overcome. First, it is difficult to consistently isolate and purify large numbers of islets from cadaver donor pancreases. Second, islets are susceptible to rejection, and many current anti-rejection drugs promote diabetes by direct or indirect damage to beta cells.

Questions about participation in the Study

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Can I still return my Annual Health Questionnaire?

You can return your completed health questionnaire at any time. If you are not sure how to answer a question, provide as much information as you can; we will contact you to follow up. Include the participant update form even if there are no changes to your contact information, or make necessary changes and add the update form to the envelope. If you need another questionnaire mailed to you, call or email and we will send another copy out to you. You can also complete the questionnaire over the phone in about 10 minutes, call or email us to get details.

What if I haven't been contacted by the Study in over a year?

Call or email us to provide your current contact information. A study coordinator will call you back with more details on how to proceed and provide the types of study participation options and medical information that we still need from you.

I told the recruiter that I was too busy for the exam, but now I have time. What should I do?

Call or email our office and a study coordinator will contact you to provide available dates, times and locations of exams. You can then schedule an exam that will be convenient for you.

What does the current exam entail?

The exam has two parts. First, a clinical exam similar to a check up at your doctors office, that includes blood pressure measurements, heart monitoring, and an update of your current health history. Second, an eye exam with fundus photography, which shows any current changes in your eyes or any retinopathy that is progressing from your diabetes. You will be paid for your participation in the exam and reimbursed for travel.