Babies with genetically low birth weight (LBW) have higher risks of developing type 2 diabetes in later life, a new study found.

In past observational studies, LBW has been linked to a higher risk of type 2 diabetes. However, these studies didn't show whether the link is causal. Lifestyle and socioeconomic factors are hard to detach in observational research. The new research looked into the genetic link between LBW and type 2 diabetes.

In the study, the researchers analyzed 3,627 cases of patients with type 2 diabetes. They compared it with the data of 12,974 controls with European ancestors from the Nurses' Health Study, which is a large-scale study of American nurses, and the Health Professionals Follow-Up Study, which is an extensive study of American male health professionals.

Using the five genetic disparities associated with LBW, which is called single nucleotide polymorphisms (SNPs), the researchers made a genetic risk score (GRS) system with a score range of one to 10.

The team found that for every one point GRS increase, type 2 diabetes risk surged by 6 percent. They also discovered that LBW was the cause of excess type 2 diabetes risks. They used a statistical method called Mendelian randomization to estimate the additional risk.

The study authors mentioned that findings from experimental and population studies suggested how limitations in early life development carry life-long influences — both functional and structural — on a person's susceptibility to developing metabolic diseases including type 2 diabetes. But the researchers believe that this is the foremost research to analyze the possible causal association between type 2 diabetes risk and LBW.

"Our findings support a potential causal relation between birth weight and risk of type 2 diabetes, providing novel evidence to support the role of intrauterine exposures in the pathogenesis of type 2 diabetes," said the researchers, including Dr. Tiange Wang from Tulane University School of Public Health and Tropical Medicine, one of the study's authors.

The research was released in the Diabetologia journal, the European Association for the Study of Diabetes publication.

According to the U.S. Centers for Disease Control and Prevention, there were 318,847 LBW babies born in 2014. "Low birth weight" is defined as weighing less than 2,500 grams (5.5 pounds) while another case, "very low birth weight (VLBW)" is described as weighing less than 1,500 grams (3.3 pounds). On the other hand, "extremely low birth weight (ELBW)" is defined as weight less than 1,000 grams (2.2 pounds).

In an early study, researchers found that premature babies with ELBW have higher chances of being bullied later in life. In another study, ELBW preemies have increased risks of experiencing health and socioeconomic difficulties as well as lifelong challenges later in life.