I was 33 years old and slim, a new mom who’d been diagnosed with gestational diabetes while pregnant. All the hard work I’d been doing for the last year to control my blood sugar levels—fitness boot camp, a diabetic diet with drastically reduced carb intake—wasn’t working anymore, so I’d booked an appointment with Jessica Castle, MD, an endocrinologist at the Harold Schnitzer Diabetes Health Center of Oregon Health and Science University.Castle told me I didn’t have type 2 diabetes, the kind characterized by insulin resistance, where the body’s cells are unable to fully use the insulin the pancreas makes. I had type 1 diabetes, an autoimmune disease that destroys the beta cells of the pancreas that produce insulin.“It’s OK,” said Castle, handing me a box of tissues. “You’re not the first person to cry in this office. You’re not even the first person to cry in this office today.” Type 2 diabetes, tied to obesity and genetic predisposition, has become an epidemic in the United States. Ninety to 95% of all 30 million diabetes cases are type 2. Type 1 diabetes is less common, representing approximately 5% of cases, with most of those surfacing during childhood. But those numbers may not be entirely accurate: A 2005 study found that about 10% of those over age 40 diagnosed as type 2 actually tested positive for the antibody cells associated with type 1 diabetes. For those younger than 35, the rate was closer to 25%. Castle says her practice sees multiple cases every year of people misdiagnosed with type 2.Many primary care doctors are not aware of the possibility of adult-onset type 1 (sometimes known as type 1.5 or Latent Autoimmune Diabetes in Adults). Consequently, if you go to see your primary care doctor with diabetes symptoms such as frequent urination and extreme thirst, she may assume it’s type 2 simply because you’re not a kid—especially if you’re carrying a few extra pounds. The cause of type 1 diabetes is not known, but it’s on the rise. Experts suspect both a genetic component and an environmental trigger. From 2001 to 2009, there was a 30% increase in type 1 among children and young people up to age 19. An exact number of new adult cases would be tough to determine, given the rate of misdiagnosis.While both type 1 and type 2 diabetes are characterized by high blood sugar and can have the same long-term consequences—kidney problems, neuropathy, and blindness among them—the treatment strategies are very different, so correct diagnosis is crucial. (No time to work out? We hear you. That’s why we created Fit in 10, an amazingly effective—fast!—workout you can do from the convenience of home. Check it out!) “People with type 1 diabetes need insulin for survival, so insulin is the primary treatment for type 1,” says Castle. If a patient with type 1 receives a type 2 diagnosis, time can be wasted trying oral medications that simply won’t work, leaving the patient with dangerously high blood sugars longer than necessary. And while type 1 in adulthood can have a slow onset, with the pancreas producing at least some insulin for a period of months or years, there’s evidence that early insulin treatment can help preserve some pancreatic function.So how do you know if your type 2 diagnosis is wrong? Castle looks at a number of factors to make a determination. All of the following would be more suggestive of type 1 diabetes, rather than type 2: Castle says correct diagnosis is also important because of the risks for associated diseases. For people with type 1, health care providers go on the lookout for other autoimmune diseases such as celiac and thyroid disease, while people with type 2 diabetes are more prone to high blood pressure, heart disease, and stroke.
You have a personal or family history of autoimmune disease.You’re younger than 40.You have a low body mass index.You’ve had diabetic ketoacidosis (DKA).Oral medications are failing to control your blood sugar levels.You needed insulin soon after diagnosis, but only in small amounts.
If Castle suspects type 1 diabetes, she orders a blood test looking for at least one of three antibodies indicative of type 1 (these are called islet cell autoantibodies, insulin autoantibodies, and glutamic acid decarboxylase antibodies). She cautions that a patient could test negative for all these antibodies and still have type 1. Also, being older or overweight doesn’t necessarily preclude you from having type 1."[Because of] the predominance of type 2 diabetes, many health care providers are less familiar with type 1," she says. “So if you’re concerned that you have type 1, seeing a specialist is a good idea.”
