Cases of insulin-requiring type 1 diabetes rose sharply in children under the age of five in Philadelphia over a two-decade span - similar to increases seen across the U.S. and Europe, according to new research.

“Why are we seeing this large increase in type 1 diabetes in very young children? Unfortunately, the answer is we don’t know,” said lead study author Terri Lipman, a professor at the University of Pennsylvania School of Nursing.

In research published in Diabetes Care, Lipman and her colleagues updated a registry started in 1985 of Philadelphia children diagnosed with type 1 diabetes.

By 2004, cases in children under the age of five increased by 70 percent as the number of diagnosed cases among all kids up to age 14 rose by 29 percent.

In 1985, 13.4 out of every 100,000 children in Philadelphia was newly diagnosed with type 1 diabetes, and in 2004, the rate was 17.2 cases per 100,000.

Hispanic children had the highest diabetes rates across all ages whereas cases in black children aged 4 and under, which had historically been very low, rose by 200 percent over the past two decades. Cases among white kids under 4 rose by 48 percent in 2000-2004, however, making theirs the fastest recent increase.

Of the two most common forms of diabetes, type 2 typically affects adults who can still produce insulin, but whose bodies cannot use the hormone to regulate blood sugar. Type 1, previously known as juvenile diabetes, typically strikes children whose immune systems have killed off insulin-producing cells in the pancreas. The disease is usually fatal if left untreated.

Type 1 diabetics must take insulin but many type 2 diabetics can control the disease with medications, diet and exercise.

Type 1 diabetes tends to start in adolescence, but especially in light of the rising number of cases in very young children, experts said parents need to be aware that toddlers and preschoolers are also susceptible.

Children from Chicago to Colorado to Finland have similarly increased rates of type 1 diabetes, though the cause eludes researchers.

“This younger group is a mystery,” said Dr. Carol Levy, a type 1 diabetes specialist at Mount Sinai Hospital in New York who was not involved in the new study. “Make sure your child has a healthy lifestyle and maintains normal body weight; whether that’s a guarantee we’re going to reduce risk, we don’t know at this point.”

Several theories vie to explain the recent rise in diabetes among youth, including vitamin D deficiencies, lack of breastfeeding and overly-hygienic environments that might cause the immune system to backfire.

“The data is controversial so that’s why I’m certainly very reluctant to propose a theory when nothing has been proven,” Lipman told Reuters Health.

“The take home message is not to be alarmist. These data confirm what has been reported worldwide and in other parts of the United States,” said Dr. Lori Laffel, of the Joslin Diabetes Center in Boston, who was not involved in the study.

“It is important to be aware of the symptoms of diabetes,” Laffel told Reuters Health. Symptoms can include extreme thirst, bed wetting or accidents in toilet-trained children or excessively wet diapers in babies, she said.

By the time the disease gets diagnosed, many infants and toddlers are very sick and the degree of illness tends to be more severe the younger the patient, experts noted.

“The young child isn’t able to talk about symptoms,” Laffel said. “A young child may be in diapers, you may not notice because diapers are often wet.”

SOURCE: Diabetes Care, online January 22, 2013.

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Increasing Incidence of Type 1 Diabetes in Youth
Twenty years of the Philadelphia Pediatric Diabetes Registry

CONCLUSIONS The incidence of type 1 diabetes is rising among children in Philadelphia. The incidence rate has increased by 29% since the 1985–1989 cohort. The most marked increases were among white children ages 10–14 years and black children ages 0–4 years. The incidence of type 1 diabetes is 18 times higher than that of type 2 in white children but only 1.6 times higher in black children.

  Received April 22, 2012.

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  Terri H. Lipman, PHD, CRNP,
  Lorraine E. Levitt Katz, MD,
  Sarah J. Ratcliffe, PHD,
  Kathryn M. Murphy, PHD, RN,
  Alexandra Aguilar, MD,
  Iraj Rezvani, MD,
  Carol J. Howe, MSN, RN2,
  Shruti Fadia, MD and
  Elizabeth Suarez, MD