For most pediatric patients with high blood sugar, the distinction between type 1 and type 2 diabetes is straightforward. However, there can be an overlap and patients who fit criteria for both conditions, making diagnosis and management more challenging.
Michelle Ditto is a California teenager and avid dancer diagnosed with type 2 diabetes 4 years ago, at age 11. “It was kind of scary,” she said. “Type 2 kinda runs in my family,” Michelle said in an interview. Her grandmother and an uncle not related by blood have type 2 diabetes, “so I knew what it was.”
About 1½ years ago, Michelle switched physicians and had some blood tests. Results showed she had two of the three antibodies indicative of type 1 diabetes. “It was a shock.”
Her dual diagnosis puts Michelle in a unique position to compare type 1 and type 2 diabetes.
“To me it just seems like there is more medication [with type 1], more insulin, more shots, so more inconvenience from my point of view as a kid,” she said. “I have to bring my kit and my insulin to school now. As a kid it's a big deal.”
“You can have a genetic predisposition to type 2 diabetes, be Hispanic and overweight, and yet develop type 1 autoimmune type. That is where diagnosis gets difficult,” Susan Clark, M.D., director of endocrinology at Children's Hospital of Orange County, Orange, Calif., told this newspaper. “That is probably 5% or less of all cases, but that overlap is there.”
“The overlap is certainly more common now than in the past because of the obesity epidemic,” Floyd L. Culler, M.D., professor of pediatrics at the University of California, Irvine, said in an interview.
The growing obesity epidemic in the United States is driving an increased incidence of type 2 diabetes among children and adolescents. That may be intuitive, but there is also a suggestion that the growing number of overweight pediatric patients contributes to increased incidence of type 1 incidence as well.
“There has been a 3%–4% increase per year in the last few years in incidence of type 1 diabetes. Some have hypothesized that it may also be related to obesity,” Francine R. Kaufman, M.D., head of the Center for Endocrinology, Diabetes, and Metabolism, Children's Hospital Los Angeles, California, said in an interview. “If you are overweight, it might accelerate destruction of the β-cells.”
She is author of a book titled, “Diabesity: The Obesity-Diabetes Epidemic That Threatens America—And What We Must Do to Stop It (Bantam, March 2005).
To further complicate diagnosis, there are some patients with diabetes who do not fit criteria for type 1 or type 2, Dr. Culler said. “The more you know the more you find patients who don't fit in a category.” Maturity-onset diabetes of the young (MODY), a subtype of non-insulin dependent diabetes mellitus, is an example.
Type 1 diabetes is an autoimmune disorder; the immune system attacks the pancreas and the cells that make insulin. With type 2 diabetes these cells become resistant to insulin, so insulin does not work well. “Early in the disease [type 2], they have high insulin levels, which leads to physical symptoms, such as a little fat around the middle and acanthosis nigricans,” Dr. Clark said.
Comorbidities are another distinction. For example, people with type 1 diabetes can have other autoimmune conditions such as autoimmune thyroid disease or celiac disease. “In type 2 diabetes, you see more diseases associated with insulin resistance, such as polycystic ovarian syndrome,” Dr. Kaufman said.
Children with type 1 diabetes generally experience a faster onset than do those with type 2 diabetes. In addition, pediatric patients with type 1 diabetes are generally younger than are those with type 2.
Other clues can aid diagnosis. “Ethnicity is a big difference. Type 1 diabetes is primarily a Caucasian disease, and type 2 diabetes pretty much affects everyone else,” Dr. Kaufman said. For example, type 2 is more common among American Indian, Hispanic, Asian, or Pacific Islander patients.
“My first recommendation to primary care physicians is to recognize abnormal weight gain early and aggressively intervene,” Dr. Clark said. “No. 2 is with a child of any age who is drinking and urinating a lot and gaining weight, to think diabetes.”
Her third recommendation is to address lifestyle issues with all children, whether an overweight patient has diabetes or not. “Every pediatrician can talk to patients and families about this, even during a short visit.”
“It's best to have a healthy lifestyle for either kind [of diabetes], and appropriate portions of the right foods. There are benefits to having an ideal body weight,” Dr. Kaufman said.