Preterm Babies At Higher Risk Of Developing Diabetes In Adulthood

CHILDREN who spend less time in the womb (a full-term pregnancy lasts at least 37 weeks) have a slightly higher risk ‒ less than 1 percent higher ‒ of developing diabetes at some point in their life, according to a Swedish studypublished in Diabetes Care. 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. It could be poor nutrition, either in the womb or right after birth that can trigger changes in the baby's hormones or metabolism, leading to abnormal processing of blood sugar, which might increase the risk of diabetes later. However, the current study didn't look at preemies' nutritional status.

Though the study was done in Sweden, the findings could have a large public health impact elsewhere as well. In 2005, WHO estimated that 12.9 million births, or 9.6 per cent of all births worldwide, were preterm. Approximately 11 million (85 per cent) of these preterm births were concentrated in Africa and Asia, while about 0.5 million occurred in each of Europe and North America (excluding Mexico) and 0.9 million in Latin America and the Caribbean.

WHO calculated that an average of 10 per cent of births worldwide occur before 37 weeks gestation, although this rate ranges between 3.8 per cent for countries in central Asia and 17.5 per cent in southern Africa. In the U.S., the Centers for Disease Control and Prevention (CDC) in Atlanta estimates that 3 of every 25 babies are delivered prematurely.

In the current study, 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.

The researchers 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.

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. Also, the rate of premature births in Sweden is about a third of the rate in the U.S.

(A recent study by Auckland University, too, has reported finding that very premature births may result in the individual facing a greater risk of type 2 diabetes in adulthood. It was found that insulin sensitivity was reduced by 40% in premature babies. Over 600 very premature births occur annually in New Zealand. Researchers believe that the low protein, high fat diet that premature babies are initially given may be behind the insulin resistance but research needs to be done to confirm this.)

Nonetheless, the researchers point 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.

In the U.S., prematurity is more of a problem in more deprived communities, and that is also the population in which more obesity is observed. So people who were premature need to pay a little more attention than people who were not to take steps to prevent diabetes.

(A similar case can possibly be made out for preterm babies born to malnourished mothers in Asia and Africa. This may possibly explain the explosion of diabetes in countries like India where the disease has reached epidemic proportions.)

However, the researchers point out, most (diabetes) risk factors are modifiable by exercising, eating a healthy diet, and quitting smoking. But they still recommend that doctors need to recognize that preterm birth is a risk factor for diabetes in later life.

For people born early, it's even more critical to avoid other risk factors for diabetes. Such risk factors include being overweight, not getting enough exercise, and having high blood pressure.