A genetic calculator has been created to determine which children will suffer from obesity when they grow up.

BarcelonaStrategies to curb the obesity epidemic have failed in recent decades and cases are rising steadily worldwide. According to projections from the World Obesity Federation, more than half of the world's population will be overweight or obese within 10 years, and strategies to combat this disease, such as lifestyle changes, surgery, and medication, are not effective and are not accessible to everyone. Now, researchers from the Universities of Copenhagen and Bristol have developed a new genetic test that can identify children at risk of suffering from severe obesity in the future, which would allow for early detection of the disease. To do so, they analyzed the genetic data of more than five million people in a study published this Monday in the journal Nature Medicine.

"The tool can predict, before the age of five, whether a child is likely to develop obesity in adulthood, long before other risk factors begin to influence their weight. Intervening at this point can have a huge impact," says Roelof Smit, a researcher at the NNF Centre Copenhagen and lead author of the study. The new test is called a polygenic risk score (PGS) and works like a calculator. The authors have identified thousands of genetic variants that increase the risk of obesity, such as some that act on the brain and influence appetite, and this tool combines them and determines a person's risk of eventually developing obesity.

With this new tool, the authors were able to explain almost a fifth (17%) of the variation in a person's body mass index, which, according to the study's findings, is much higher than other diagnostic tools studied so far. To create the calculator, they used the "largest and most diverse genetic dataset in history," with more than five million participants, obtained from information from the Genetic Investigation of Anthropometric Traits (GIANT) consortium and the genetic testing company 23andMe.

"Twice as effective"

Once developed, the researchers tested the new tool with the physical and genetic data of more than 500,000 people and found it to be "twice as effective as the best previous method" at predicting the risk of developing obesity. University of Bristol researcher and second author of the study, Kaitlin Wade, explains that obesity is a major public health problem involving many factors, such as environment, lifestyle, behavior, and genetics, among others, and some of these "originate in childhood," so this tool can help them anticipate.

The team also studied the relationship between the genetic risk of obesity and the impact of lifestyle-based weight-loss interventions, such as good nutrition and exercise. The researchers also found that people with a higher genetic risk responded better to these healthy lifestyle habits, but also regained the weight more quickly when they stopped exercising and eating healthy. However, the study has some limitations, such as the fact that the participants were predominantly people of European descent. Therefore, further research is needed with more representative population groups.