A groundbreaking genetic test has emerged that can predict which children are at the highest risk of developing a high body mass index (BMI) later in life. Developed by an extensive team of international researchers, this test utilizes a method known as a polygenic score (PGS), which assesses genetic variations to forecast specific traits, in this case, BMI.
According to genetic epidemiologist Roelof Smit from the University of Copenhagen, the test can identify potential obesity risks before a child reaches the age of five. “What makes the score so powerful is its ability to predict, before the age of five, whether a child is likely to develop obesity in adulthood, well before other risk factors start to shape their weight later in childhood,” Smit explained. Early intervention could significantly influence a child’s health trajectory.
Despite its promising capabilities, the test comes with caveats. Genetics accounts for only a portion of BMI risk, and there is a growing consensus among health experts to reassess BMI as a measure of obesity and overall health. Nevertheless, researchers assert that the new PGS test demonstrates up to double the accuracy of previous models.
The PGS was constructed from a vast database containing genetic information from over 5.1 million individuals. Researchers validated the test through various health databases that tracked genetic data and BMI over time for hundreds of thousands of individuals. When combined with other BMI predictors, the PGS showed that higher scores correlated with increased adult weight gain.
Significant Findings and Implications
The accuracy of the PGS in predicting BMI variation varied by age and ancestry. For instance, PGS scores at age five accounted for 35 percent of BMI variation by age 18. In contrast, for middle-aged Europeans, it explained 17.6 percent of the variation. The predictive power dipped significantly for other demographics, such as rural Ugandans, where the score accounted for only 2.2 percent. Researchers attribute this discrepancy to underrepresentation in training data and the greater genetic diversity found in African populations.
Another noteworthy discovery from the study indicates that individuals with a stronger genetic predisposition to higher BMI may initially respond better to weight loss programs, losing more weight during the first year. However, they are also more prone to regaining weight later. “Our findings emphasize that individuals with a high genetic predisposition to obesity may respond more to lifestyle changes and, thus, contrast with the determinist view that genetic predisposition is unmodifiable,” the researchers noted in their published paper.
The potential for early prediction of BMI through genetic testing offers a critical opportunity for families to establish healthier lifestyle habits. By identifying at-risk children, parents can actively engage in promoting better nutrition and physical activity, potentially mitigating the risk of obesity in the future.
“This new polygenic score is a dramatic improvement in predictive power and a leap forward in the genetic prediction of obesity risk, which brings us much closer to clinically useful genetic testing,” said Ruth Loos, a geneticist also from the University of Copenhagen.
The findings of this research have been published in Nature Medicine, contributing to the growing body of knowledge surrounding genetics and health. As science advances, these tools may provide families and healthcare providers with essential insights into managing health risks from an early age.
