London, Dec 2 (IANS): Dispelling common misconception that Type-1 diabetes is predominantly a "disease of childhood", a new study says that adults are as likely to develop the condition as children.

More than 40 per cent of Type-1 diabetes cases occur after the age of 30, said the study published in the journal Lancet Diabetes & Endocrinology.

But adults with Type-1 diabetes are often misdiagnosed as they are thought to have Type-2 diabetes at first, the researchers pointed out.

"Diabetes textbooks for doctors say that Type-1 diabetes is a childhood illness. But our study shows that it is prevalent throughout life," said Richard Oram from the University of Exeter in Britain.

"The assumption among many doctors is that adults presenting with the symptoms of diabetes will have Type-2 but this misconception can lead to misdiagnosis with potentially serious consequences," Oram said.

Distinguishing between Type-1 or Type-2 diabetes matters as it affects the treatment needed.

In Type-1 diabetes, immune cells destroy the body's insulin producing beta cells and people need to be injected insulin to control blood sugar levels.

With Type-2 diabetes there is still insulin produced so it can be treated initially with diet and tablet therapy.

Among the adults with Type-1 diabetes to have been misdiagnosed is Theresa May, the Prime Minister of Britain, who was initially told by doctors she had Type-2 diabetes and given tablets which did not control her blood sugar.

"The Prime Minister is an example of someone who was misdiagnosed in this way at first. This study should raise awareness that Type-1 diabetes occurs throughout adulthood and should be considered as a diagnosis," Oram said.

But Type-1 cases are harder to recognise and correctly diagnose in adults because far more people develop Type-2 diabetes in later life.

A crucial clue to the possibility of adult-onset Type-1 diabetes is the failure of tablets to control blood glucose. Adult-onset Type-1 patients are also likely to be slim compared to Type-2 patients who are often obese, the researchers said.

The study used a novel genetic analysis to identify Type-1 diabetes in adults. This allowed them to identify cases of Type-1 diabetes not picked up by the patients' doctors.