SAN FRANCISCO – The widely held belief that America’s obesity epidemic has resulted in an equally staggering number of children with type 2 diabetes may well be off the mark, according to Dr. Philip Zeitler.
"This is not an epidemic; type 2 diabetes in youth remains rare," said Dr. Zeitler, head of endocrinology, Children’s Hospital Colorado, Denver.
Dr. Phil Zeitler
Although the prevalence of type 2 diabetes (T2D) in youth has risen substantially over the last decade, the best evidence to date from the SEARCH for Diabetes in Youth Study (Pediatrics 2006;118:1510-8) indicates that T2D is rare in children younger than 10 years of age (0.79/1,000), regardless of race or ethnicity.
Another, more recent look at prevalence by the SEARCH investigators in 2009 found the estimated total prevalence of T2D is, if anything, a little lower than the 2006 estimate (Diabetes Care 2014;37;402-8), he said.
"So the little 5-year-old child you hear about in the paper with diabetes either is extremely rare or doesn’t have type 2 diabetes," Dr. Zeitler said at the annual advanced postgraduate course held by the American Diabetes Association.
After 10 years of age, newly diagnosed cases represent about 15% of all diabetes cases in teenagers who are white, 46% of cases in Hispanic youth, 58% in blacks, 70% in Asian/Pacific Islanders, and 86% in Native Americans.
These numbers are "striking, even horrifying perhaps," said Dr. Zeitler, but are actually quite low when one considers the total number of cases is only about 3,700 youth under age 20 diagnosed with T2D in the United States annually.
To put this in context, an estimated 1.9 million adults, aged 20 and older, were newly diagnosed with diabetes in 2010, according to the Centers for Disease Control and Prevention.
The argument could be made that juvenile T2D is simply lurking under physicians’ radar. After all, 50% of adult cases are undiagnosed or picked up on screening. This is not the case with children, "even at the peak age in the highest-risk population," Dr. Zeitler said.
In fact, just 0.4% and 0.1% of eighth graders with a body mass index exceeding the 85th percentile had diabetes by fasting criteria and, more importantly, by oral glucose tolerance testing in the STOPP-T2D (Studies to Treat or Prevent Pediatric Type 2 Diabetes) trial (Diabetes Care 2006;29:212-7).
For those children who do get diabetes during this period, however, there may be a phenomenon that could be referred to as "pubertal diabetes," Dr. Zeitler said. Insulin resistance worsens as children enter puberty, but as they come out the other side and demand on the beta-cell decreases, many are able to compensate.
Indeed, in a small study involving 117 obese children and adolescents, 32% of those with impaired glucose tolerance, not surprisingly, progressed to diabetes within about 2 years, but another 32% regressed to normal glucose tolerance with no intervention (Diabetes Care 2005;28:902-9).
"This is highly analogous to something else we see all the time – otherwise healthy people who go into a certain state and develop diabetes, but when they get out of that state are either still diabetic or normal," he said. "This really appears to be an analog of gestational diabetes."
Importantly, for adolescents who are ultimately diagnosed with T2D, loss of beta-cell function is the primary predictor of failure to maintain glycemic control, Dr. Zeitler said.
He reported research support from the National Institute of Diabetes and Digestive and Kidney Diseases and the American Diabetes Association and clinical trial design consultancy for Daiichi-Sankyo, AstraZeneca, Merck, Janssen Pharmaceuticals, and Gilead Pharmaceuticals.