• Posted June 26, 2024

Obesity May Be Even Less Healthy If Child Was Born Underweight

Low-birth-weight newborns have a higher risk of health complications if they become obese as children, a new study has found.

Obese children who were low-birth-weight babies have a higher risk of insulin resistance, fatty liver and other health problems, researchers found.

The study "supports the theory that individuals who were born low birth weight, or who are genetically predisposed to low birth weight, may be more vulnerable to health hazards -- such as excess visceral fat -- throughout the course of life,"said lead researcher Sara Stinson, a postdoctoral research fellow with Oslo University Hospital in Norway.

Previous studies already have tied high birth weight to an increased risk of overweight and obesity, and low birth weight to an increased risk of type 2 diabetes.

To understand these links more, researchers analyzed data on more than 4,000 children. The data included birth weight, BMI, medical records, blood samples and a genetic health risk score associated with birth weight. 

They found that a low-birth-weight child's insulin sensitivity suffers if they put on excess pounds.

 "In children with obesity, we see near normal insulin sensitivity in children born with a high birth weight and drastically decreased insulin sensitivity in children with low birth weight,"researcher Dr. Pauline Kromann Reim, a doctoral student with the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen in Denmark, said in a university news release.

This could be due to differences in the way the body stores fat, researchers speculated.

A healthy body normally stores fat in cells beneath the skin, called subcutaneous fat.

But subcutaneous fat stores can be underdeveloped in children born underweight, researchers said.

That means the skin-layer fat cells can't expand as needed to store more fat. Instead, the body stores fat around the organs, which is called visceral fat.

Subcutaneous fat isn't dangerous to health, and is in fact essential for proper body function. On the other hand, higher levels of visceral fat have been tied to elevated risk of many health problems, including heart disease and type 2 diabetes.

Researchers also found low birth weight linked to higher levels of fat in the liver, which decreases insulin sensitivity. This could explain why low birth weight kids are at higher risk of type 2 diabetes, even in childhood.

These results indicate that kids with lower birth weight need specific approaches to prevent and treat obesity and its related diseases, researchers said.

The new study was published June 24 in the journal EBioMedicine.

More information

The March of Dimes has more on low birth weight.

SOURCE: University of Copenhagen, news release, June 24, 2024