|
By Melissa Tennen, HealthAtoZ writer
You've heard of diabetes type 1 and type 2. But how about type 1.5?
It's not entirely new. But in recent years researchers and health care providers are noticing that it is showing up more often.
"For a long time, we thought type 1 mostly happened to children. Now we know that in older people its symptoms can develop at a slower rate - four to five years. With children, it seems to happen almost overnight," says Eugene J. Barrett, M.D., former president of the American Diabetes Association, professor of internal medicine and pediatrics at the University of Virginia Health System in Charlottesville.
Type 1.5 diabetes has virtually the same underlying cause as type 1. The difference is that type 1.5 happens in people older than 25, whereas type 1 happens in childhood, the teen years and young adulthood. People as old as 80 have been diagnosed with type 1.5.
Type 1 diabetes means the person has high blood glucose levels because the body does not make enough of the hormone insulin. This happens when the immune system attacks the insulin-producing beta cells in the pancreas and destroys them, causing the pancreas to make little or no insulin. The body needs insulin to use sugar, which is the basic fuel for cells. Insulin allows the sugar in the blood to enter the cells.
Type 2 occurs in 90 percent to 95 percent of diabetic cases and can happen at any time during life. Unlike type 1, type 2 is not an autoimmune disease and happens when the body becomes resistant to insulin and cannot effectively respond by producing more insulin. People who do not exercise enough and do not maintain a healthy weight are more likely to develop this disease. No one knows why type 1 happens.
"We don't call type 2 adult-onset diabetes anymore because children can get it, too," Barrett says.
"There is no doubt older people are being diagnosed with type 1 diabetes more and more frequently," says Simeon Margolis, M.D., Ph.D., professor of medicine, endocrinology and biological chemistry at the Johns Hopkins University School of Medicine in Baltimore, Md. "One of the recent presidents of the ADA says he remains surprised whenever an older patient has it. It isn't common. It is recognized more widely, but it isn't common."
Different treatment needed
A case study appearing in the journal Clinical Diabetes described a 41-year-old man whose weight was normal. He complained of excessive thirst and hunger and urinated often. When the man was diagnosed with type 2, he regularly exercised, did not smoke, did not abuse alcohol or drugs and did not have any other health problems that he knew of. However, in the 15 months following diagnosis, he lost 35 pounds even though he continued to exercise and followed a low-fat, low-sugar diet - a typical treatment for type 2 diabetes.
After more blood work, his health care providers started treating him for type 1 diabetes by increasing his food intake to help him gain weight and having him take daily insulin injections. This approach appeared to control the symptoms.
"The danger is the initial failure to diagnose it," Margolis says. A misdiagnosis can happen when the person does not have the body type or age, typical for type 1 diabetes. One clue may be someone who is slender and otherwise healthy. It becomes confusing in someone who, for example, may be in their 30s, fit and trim but has mildly elevated blood glucose levels. Such a person does not fit into traditional categories for diagnosis.
It is not clear yet if people with type 1.5 have the same high risk for cardiovascular problems as individuals with type 2. Cardiovascular disease is the leading cause of diabetes-related death. People with diabetes are two to four times more likely to develop cardiovascular disease. At least 65 percent of people with diabetes die from heart disease or stroke.
"If adults develop type 1 diabetes, they will not develop type 2," Margolis says.
Researchers do not know just how many people may have type 1.5 or how many might be misdiagnosed as type 2. Researchers do know a close genetic link plays a role. The National Institute of Diabetes and Digestive and Kidney Diseases is studying how type 1 can be delayed or prevented and is recruiting participants for trials.
Calling it type 1.5 may be misleading. Type 1.5 is not a subset of type 1. Some researchers are calling it latent autoimmune diabetes of adulthood (LADA) or slow onset type 1, although no official name has been given. Type 1.5, one of several names being used to describe the disease, appears to be the most common.
"I'm not sure that the nomenclature is quite appropriate," Barrett says. "It looks very similar to type 1, but it is not in between type 1 and type 2. Type 1 and 2 are very different diseases. It's probably not a nomenclature that fits."
This article was reviewed and updated June 2007.
Return to the previous page
|
