Cases of 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 US 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 study leader Dr Terri Lipman from the University of Pennsylvania School of Nursing.
In research published January 22 in Diabetes Care, Dr 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%, as the number of diagnosed cases among all kids up to age 14 rose by 29%.
In 1985, 13.4 out of every 100 000 children in Philadelphia were newly diagnosed with type 1 diabetes. 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 four and under, which had historically been very low, rose by 200% over the past two decades. Cases among white kids under four rose by 48% in 2000-2004, however, making theirs the fastest recent increase.
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.
Breastfeeding and overly-hygienic environments
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 (are) controversial so that's why I'm certainly very reluctant to propose a theory when nothing has been proven," Dr 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," she 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," Dr, Laffel said. "A young child may be in diapers, you may not notice because diapers are often wet."
(Trevor Stokes, Reuters Health, February 2013)
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