People who are born prematurely may have an increased risk of going on to develop type 2 diabetes, a new study suggests.

According to US scientists, there is ‘growing evidence that foetal and early life events may result in permanent metabolic alterations, such as type 2 diabetes'.

They decided to test the theory that premature birth is associated with elevated blood insulin levels at birth that can continue into early childhood. Elevated blood insulin levels provide indirect evidence of insulin resistance, which is a risk factor for diabetes.

The scientists looked at almost 1,400 children born between 1998 and 2010. These were followed up between 2005 and 2012. Insulin levels were measured at the time of birth and during early childhood.

The study found that insulin levels were inversely linked with the gestational age of babies at their birth and in early childhood. In other words, premature babies were more likely to display high insulin levels at birth and in their early years.

The average insulin level at birth for full-term babies was 9.2 µIU/mL (micro international units per milliliter). In babies born at less than 34 weeks gestation, this figure rose to an average of 18.9 µIU/mL.

When the levels were checked in early childhood, they were found to be higher in all those who had been born early - irrespective of how early - compared to those born at full-term.

"These findings provide additional evidence that preterm birth may be a risk factor for the future development of insulin resistance and type 2 diabetes," the scientists said.

Details of these findings are published in the Journal of the American Medical Association.