In 2000, my first paper on adult-onset Type 1 diabetes was published in the newsletter of the International Diabetic Athlete Association (IDAA), a now-defunct organization. I feared that I would receive hate mail for what I wrote, particularly for blasting ADA and JDRF, but instead I received so many email responses to the effect of, “thank you, finally someone has written the truth about Type 1 diabetes.” When I read my words of 17 years ago, I realize we still have a long way to go, but in fact much progress has been made (for example, JDRF has a program and brochure for people with adult-onset Type 1 diabetes). Here is my article from 2000, with a few 2017 updates as noted:
ONSET OF TYPE 1 DIABETES IN ADULTS:
THE NEED FOR CORRECT DIAGNOSIS AND TREATMENT
Type 1 or autoimmune diabetes has long been thought of as a disease of childhood; in fact, its previous designation was juvenile diabetes. Only in recent years, with the advent of antibody testing, have some in the medical community recognized that Type 1 diabetes affects people of all ages, and in fact the majority of people who are newly diagnosed with Type 1 diabetes are adults. In 1997, the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus stated that, “immune mediated diabetes commonly occurs in childhood and adolescence, but it can occur at any age, even in the eighth and ninth decades of life” (The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus, 1998). However, the medical community has been slow to recognize this, and Type 1 diabetics diagnosed as adults are still treated as abnormalities and frequently given inappropriate treatment for the disease they have. All too often, they are diagnosed with Type 2 diabetes, which is a fundamentally different disease not only clinically but genetically (Saudek, Rubin, and Shump, 1997), and the methods of treatment for the two diseases are also different. The misdiagnosis typically results in under-treatment, and causes needless suffering. Many International Diabetic Athletes Association (IDAA) members were diagnosed with Type 1 diabetes as adults, including Linda McClure, the IDAA Executive Director, who was diagnosed at age 36. I was diagnosed with Type 1 diabetes at age 35, although I was briefly treated as if I had Type 2 diabetes and was sent to Type 2 diabetes education classes. I discovered that the diabetes care community is not set up to deal with adults who are newly diagnosed with Type 1 diabetes, which is a situation that I believe needs to change.
The United States Centers for Disease Control and Prevention (CDC) states that the number of new cases of diabetes diagnosed per year is 798,000, and that Type 1 diabetes may account for 5% to 10% of all diagnosed cases of diabetes (from the CDC web site). In fact, these percentages only include those who have been correctly diagnosed, and many recent studies indicate that that Type 1 diabetes is undercounted. All too often, those with Type 1 such as myself who acquire the disease as adults are misdiagnosed as having Type 2. Numerous studies, particularly recent ones that used antibody testing (islet cell antibody [ICA], anti-glutamic acid decarboxylase [anti-GAD] antibodies, etc.), indicate that approximately 10% of adults newly diagnosed with Type 2 diabetes in fact have the autoimmune markers for Type 1 diabetes and have been misdiagnosed (Wroblewski, et.al., 1998). In the landmark United Kingdom Prospective Diabetes Study (UKPDS) of Type 2 diabetes, 10% of the people that supposedly had Type 2 had ICA and/or anti-GAD antibodies, and clearly had Type 1 diabetes (Zimmet et. al., 1999). The Endocrine Society estimates that as many as 20% of the people diagnosed with Type 2 diabetes actually have Type 1 diabetes (Endocrine Society web site). The web site for the Lehigh University Diabetes Frequently Asked Questions (FAQs) states that, “Latent autoimmune diabetes in adults (LADA, or Type 1 diabetes in adults) may constitute as much as 50% of non-obese adult-onset diabetes.”
It is important that the type of diabetes a patient has is correctly assessed. As stated previously, adults who acquire Type 1 diabetes should be put on exogenous insulin as early as possible, to control glucose levels, prevent further destruction of residual beta cells, and reduce the possibility of diabetic complications. However, these are very clinical outcomes that fail to address the “human side” of misdiagnosis. Those of us who have Type 1 diabetes but were initially diagnosed with Type 2 diabetes often suffered needlessly while on oral medications for Type 2 diabetes until we received appropriate treatment for the disease that we have (exogenous insulin). The examples below describe the human impact of misdiagnosis.
June Biermann, prolific author of books on diabetes including The Diabetic’s Sports and Exercise Book, was diagnosed with Type 2 diabetes in 1967 at age 45, even though she failed to meet the criteria associated with Type 2 diabetes. June was prescribed various oral medications for Type 2 diabetes, which did not adequately control her blood sugars, and after one year of much suffering and further weight loss (and several doctors), June was treated with exogenous insulin. The standard for that time was one injection per day of NPH insulin. Although for many years June referred to herself as a Type 1-1/2 diabetic, today she probably would be called a late-onset Type 1 diabetic. Thirty years after her initial diagnosis as a Type 2 diabetic, June was given a C-peptide test, which indicated that her body did not produce any insulin. June says, “The medical profession wanted to believe that I did not exist and that the problem was with me, when in fact it was the medical profession that ignored Type 1 diabetes in adults” and that she “has always felt misunderstood and ignored, and that [she] was a freak to the medical profession.” June now does five or more injections per day of Humalog and NPH purified pork insulin, tests her blood sugar 7 to 8 times per day, and is looking forward to the introduction of glargine, the long-acting insulin analog without a peak.
Clearly it would be helpful if both ADA and JDRF acknowledged the full incidence of Type 1 diabetes in people of all ages.
If you are newly diagnosed, and unsure if you have Type 1 or Type 2 diabetes, you can be tested for anti-GAD antibodies (2017 note: autoantibodies include GAD, ICA, IA-2, IAA, and ZnT8). If an anti-GAD antibody test is performed when diabetes is first diagnosed, a positive result means you have Type 1 diabetes. Also, the C-peptide test, which is a measurement of the body’s natural production of insulin, can be a way to gauge whether you have Type 1 or Type 2 diabetes (Connors, 2000).
All people deserve appropriate medical care for the disease that they have. It is imperative that the true incidence of Type 1 diabetes in adults be known, and that the diabetes medical community recognizes us, so that we who acquire the disease as adults can live the best lives possible.
Connors, Thomas, 2000. “An Old Test Teaches Doctors New Tricks: C-Peptide Exam Becoming an Accepted Tool for Diabetes Treatment.” Diabetes Interview, September.
The Diabetes Control and Complications Trial Research Group, 1998. “Effect of intensive therapy on residual beta-cell function in patients with Type 1 diabetes in the Diabetes Control and Complications Trial. A randomized, controlled trial.” Annals of Internal Medicine, April 1, 1998. 128(7):517-23.
Dolger, H., and B. Seeman, 1958. How To Live With Diabetes. W.W. Norton and Company, New York.
The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus, 1998. “Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus.” Diabetes Care, Volume 21, Supplement 1.
Karl, D.M, and M.C. Riddle, 2000. “Not Just For Kids.” Diabetes Forecast, November.
Lehigh University Diabetic Mailing List, Frequently Asked Questions, “What is Latent Autoimmune Diabetes in Adults?” June 27, 1996.
Saudek, C.D., R.R. Rubin, and C.S. Shump, 1997. The Johns Hopkins Guide to Diabetes For Today and Tomorrow. The Johns Hopkins University Press, Baltimore.
Wroblewski, M., et al., 1998. “Gender, Autoantibodies, and Obesity in Newly Diagnosed Diabetic Patients Aged 40-75 Years.” Diabetes Care, Volume 21, Number 2.
Zimmet, P., et al., 1999. “Crucial Points at Diagnosis. Type 2 Diabetes or Slow Type 1 Diabetes.” Diabetes Care, Supplement 2: B59-64.