For years, distinguishing between the various types of diabetes was pretty straightforward: “Juvenile diabetes,” an autoimmune disease, was diagnosed primarily in children and teenagers when their own body’s immune system destroyed the insulin-producing (beta) cells in their pancreas. “Adult-onset diabetes” occurred in adults and was generally associated with insulin resistance and often with overweight. And “gestational diabetes” occurred in pregnant women and disappeared once the pregnancy was over.
In the past 20 years, however, determining what type of diabetes a person has has become more of a challenge. In large part, that’s because more and more children and teenagers are now being diagnosed with Type 2 diabetes — the type that occurred predominantly in adults in generations past. Most of these children and teens are overweight. At the same time, it’s becoming clearer that Type 1 diabetes can occur at any age and sometimes occurs in people who are overweight. In addition, another type of diabetes, called latent autoimmune diabetes in adults, or LADA, that shares some characteristics with both Type 1 and Type 2 diabetes, has been recognized. Muddying the water further is the realization that diabetic ketoacidosis, an acute, life-threatening complication of diabetes that is caused by a lack of insulin, can occur in people with Type 2 diabetes — not just in people with Type 1, as was previously thought. And while gestational diabetes is still diagnosed only in pregnant women, it is sometimes discovered that what is thought to be gestational diabetes is really Type 1 or Type 2 diabetes that happens to start during pregnancy.
The incidence of diabetes has increased so greatly around the world in the past 20 years that health organizations and media outlets alike often refer to the “diabetes epidemic.” Most of the new cases of diabetes are Type 2 diabetes, which accounts for 90% to 95% of all diabetes cases. The world is concurrently experiencing an “obesity epidemic,” and while it is not universally accepted that overweight and obesity cause Type 2 diabetes, it is generally accepted that overweight and obesity are environmental risk factors for developing Type 2 diabetes.
The incidence of Type 1 diabetes, which accounts for about 5% to 10% of all diabetes cases and is not generally thought to be linked to overweight or obesity, is also on the rise, albeit at a slower rate than Type 2 diabetes. That means that people with Type 1 diabetes are still a distinct minority within the population of people who have diabetes. And adults with Type 1 diabetes tend to be less visible members of that minority, with much of the research and media attention focused on children with Type 1. Many adults with Type 1 diabetes have found that this minority status can present some medical challenges, as well as social and emotional challenges.
The challenge of diagnosis When Type 1 diabetes starts in adulthood, its symptoms usually come on quite suddenly and are the same as those that occur in children with Type 1 diabetes; they include weight loss, constant thirst and urination, and nausea. (In contrast, symptoms of Type 2 diabetes and of LADA tend to come on more gradually, sometimes over a period of years.) Being diagnosed correctly and starting insulin therapy immediately is of utmost importance for people with Type 1 diabetes: Because their pancreases are no longer producing any insulin (or virtually none), diabetic ketoacidosis can set in quickly. Oral medicines that lower blood glucose in people with Type 2 diabetes are not effective in people with Type 1. In spite of the similarity of symptoms, however, when an adult with symptoms of diabetes is found to have high blood glucose, the assumption is usually that the person has Type 2 diabetes because of age. If the adult is overweight, the chances may be even higher that the doctor will diagnose Type 2 diabetes.