(Reuters Health) – Babies born early may have a small increased risk of diabetes when they grow up, a Swedish study says.

A full-term pregnancy lasts at least 37 weeks. Children who spent less time in the womb had a slightly higher risk — less than 1 percent higher — of developing diabetes at some point in their life, according to the paper in Diabetes Care.

Doctors need to “recognize that preterm birth is a risk factor for diabetes in later life,” Dr. Casey Crump, assistant professor of medicine at Stanford University in Palo Alto, California told Reuters Health.

And for people born early, “it’s even more critical” to avoid other risk factors for diabetes, said Crump, who co-authored the study. Such risk factors include being overweight, not getting enough exercise, and having high blood pressure.

The study was done in Sweden, but the findings could have a large public health impact elsewhere, too, Crump said. In the U.S., for instance, the Centers for Disease Control and Prevention (CDC) in Atlanta estimates that 3 of every 25 babies are delivered prematurely.

The researchers used a national prescription database to track the use of diabetes medications by roughly 630,000 people born in Sweden between 1973 and 1979. Roughly 28,000 of those were born prematurely.

Crump’s team found that about 15 out of 1000 preemies had diabetes by the time they were in their twenties and thirties, compared to about 12 of 1000 full-term babies.

Most of the prescriptions were for insulin without oral medications, which indicates that the majority of cases were type 1 diabetes.

The increased risk of diabetes applied not only to people who were born very prematurely, but also those born just a week or two early.

The researchers don’t have a good explanation yet for why early birth might be linked with later diabetes. Crump points out that poor nutrition, either in the womb or right after birth, can trigger changes in the baby’s hormones or metabolism that can lead to abnormal processing of blood sugar, which might increase the risk of diabetes later. The current study didn’t look at preemies’ nutritional status, however.

In general, diabetes is less common in Sweden than in the U.S., where it affects about 17 out of every 1000 people in the 25 to 35 age group, Crump said. Also, the rate of premature births in Sweden is about a third of the rate in the U.S.

But Crump points out that premature birth is not as important a risk factor for diabetes as obesity and family history.

About two thirds of Americans are overweight, according to the CDC.

“I think prematurity is more of a problem in more deprived communities, and that is also the population in which you see more obesity,” said Caroline Fall, professor of international pediatric epidemiology at the UK’s University of Southampton.

People who were premature “need to pay a little more attention than people who were not” to take steps to prevent diabetes, Fall, who was not involved in the study, told Reuters Health.

“The good news,” Crump said, “is that most (diabetes) risk factors are modifiable,” by exercising, eating a healthy diet, and quitting smoking.

This article was published in www.reuters.com on 5 April 2011.