New data from landmark trial reveal long term effects of preterm birth

A study based at the Liggins Institute has shown that adults who were born even moderately preterm have a greater risk of developing type 2 diabetes than those born at term. However, it did not appear that this risk was passed on to their children if the children were born at term.

The results of the study by researchers at The University of Auckland, Starship Children’s Hospital and the National Research Centre for Growth and Development, have been posted online ahead of print in the highly regarded journal Diabetes.

The study is one of a number that have followed the development of babies born during a world-famous clinical trial conducted at Auckland’s National Women’s Hospital in the early 1970s by Professors Graham Liggins and Ross Howie. That trial was the first to show that giving steroids to women in premature labour vastly improved the survival chances of babies born preterm.

The current study investigated the effectiveness of the body’s natural hormone insulin in regulating glucose levels in adults , now aged 34-38 years, who were born before 37 weeks’ gestation compared with a matched group born at term. Investigators also assessed glucose metabolism in children of the study subjects to see if changes had been passed on to a second generation.

“Insulin is an important hormone controlling growth and metabolism,” says Associate Professor Paul Hofman, who led the investigation.

“It is responsible for transporting glucose, fat and protein into cells. When insulin does not work effectively the body’s organs become less sensitive to its action. Reduced insulin sensitivity is a major risk factor for type 2 diabetes, cardiovascular disease, high blood lipid levels and some forms of cancer.”

He says that previous research has shown evidence of impaired insulin sensitivity in children and young people who were born very preterm but this is the oldest cohort to date to show that the condition worsens with age.

“This puts preterm survivors at risk of early onset type 2 diabetes, hypertension, stroke and ischaemic heart disease. However it also indicates that if we can improve their insulin sensitivity we may be able to prevent these problems occurring.

“The study has substantial implications for public health since preterm survivors constitute 6% of all births in New Zealand and around 12% in the United States,” he says.