Incidence of Type 1 diabetes in children aged under five in Europe is set to double by 2020 over 2005 levels while cases among the under-15s will rise by 70 percent, according to a study.
The trend, based on diagnosed cases between 1989-2003, will be highest in the former Communist countries of eastern Europe, it warns.
The paper, published online by the British journal The Lancet, says the increase is so dramatic that it cannot be attributed to genes alone.
Instead, "modern lifestyle habits" are the likely culprits, it says.
Diabetes, a potentially lethal condition, affects 246 million people worldwide and is expected to affect some 380 million by 2025, according to the International Diabetes Federation (IDF) website.
Type 1 diabetes generally occurs in childhood and early adolescence.
The immune system destroys cells in the pancreas that make insulin, the hormone that breaks down glucose into other forms of energy, and this causes sugar levels in the blood to rise dangerously.
Experts say the disorder seems to be caused by a mix of genetic vulnerability and environmental factors.
These include increases in weight and height, less exposure to early infections in childhood and delivery by caesarean section.
Type 2 diabetes, which affects far more people than Type 1, occurs when there is insufficient insulin or cells become insensitive to the insulin that is produced.
It is closely associated with chronic obesity, which has become an epidemic in the industrialised world as a result of sedentary lifestyles and the switch to sugary and fatty foods.