Scientists have developed a powerful new tool capable of predicting a child’s risk of developing obesity later in life. The innovation, known as a polygenic risk score, uses genetic information to assess susceptibility to obesity and may pave the way for early, targeted interventions.
This score evaluates millions of genetic variations and has proven to be twice as accurate as previous predictors of obesity risk. Researchers found it could explain 17.6% of the variation in body mass index (BMI) using data from people in the UK. Crucially, the genetic score begins to show predictive strength from as early as two and a half years old and continues to be relevant through adolescence and adulthood.
Developed by researchers from the University of Copenhagen and the University of Bristol, the tool was tested on data from over 500,000 individuals, including participants from the long-running “Children of the 90s” study. This project follows families in the UK to examine how genetic and environmental factors shape health across generations.
The study showed that children with higher genetic scores were more likely to gain weight earlier in life, even before lifestyle or environmental influences had significant impact. According to lead author Roelof Smit, this early prediction ability opens the door for proactive measures before typical obesity risk factors become established.
BMI has long been used as a common measure for weight assessment, but researchers argue it is not effective at identifying long-term obesity risk in children. Unlike BMI, which can fluctuate with growth and lifestyle, the genetic risk is constant and set at conception. This makes the polygenic score a more consistent and reliable tool for early screening.
In adults undergoing intensive lifestyle changes—such as 150 minutes of weekly exercise and dietary modifications—those with higher genetic risk scores initially lost more weight than others. However, they were also more prone to regaining it once the intervention ended, suggesting a complex relationship between genetic predisposition and behavioral change.
Despite the influence of genetics, researchers emphasized that outcomes are not fixed. Individuals with a high genetic risk can still benefit from behavioral interventions, especially when started early. The findings highlight the potential of precision medicine in addressing obesity by identifying at-risk individuals early and tailoring support accordingly.
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