New genetic tool spots obesity risk as early as age five
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A new genetic tool called a polygenic risk score (PGS) uses DNA data from over five million people to predict adult obesity risk from early childhood.
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The score explains about 17% of BMI variation and is twice as effective as previous genetic tests for obesity.
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Children with higher genetic risk responded more to interventions (diet, lifestyle) but also regained weight faster after programs ended.
Obesity is an ongoing global challenge, and while adults can choose lifestyle changes or even surgery these aren't always available or effective later in life.
That raises a question: what if we could spot risk long before problems emerge?
Researchers from the University of Bristol identified a polygenic risk score (PGS), a DNA-based tool that can flag kids predisposed to adult obesity even before their fifth birthday.
What makes the score so powerful is the consistency of associations between the genetic score and body mass index before the age of five and through to adulthood timing that starts well before other risk factors start to shape their weight later in childhood, researcher Roelof Smit said in a news release. Intervening at this point could theoretically make a huge impact.
The study
Researchers analyzed genetic data from more than five million individuals including contributions from the GIANT Consortium and 23andMe to build both ancestry-specific and multi-ancestry versions of the PGS.
The score aggregates the influence of thousands of subtle genetic variants many tied to brain-based appetite regulation into one overall obesity-risk index.
Next, they tested the score on over 500,000 people with genetic and BMI data, including participants in the UK-based Children of the 90s cohort study. That allowed the team to compare predicted risk with actual weight trajectories over time.
The results
Heres a breakdown of the results:
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The new PGS explained nearly 17% of the differences in body mass index about twice the predictive power of earlier tools.
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Associations between the PGS and BMI emerged before age five and persisted into adulthood, making it particularly useful for early risk detection.
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In followup studies, children with higher genetic risk lost slightly more weight during lifestyle intervention programs (like diet and exercise), but also regained weight more rapidly after the interventions ended. The researchers stress that genetics isnt destiny behavioral strategies still matter.
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However, the score performed better in individuals with European ancestry compared to those with African ancestry, despite attempts to include diverse groups. That highlights the need for broader genetic representation in future research.
"Obesity is a major public health issue, with many factors contributing to its development, including genetics, environment, lifestyle, and behavior, researcher Dr. Kaitlin Wade said in the news release. These factors likely vary across a person's life, and we believe that some of these originate in childhood.
We hope this work will contribute to detecting individuals at high risk of developing obesity at an earlier age, which could have a vast clinical and public health impact in the future."
Posted: 2025-07-30 19:22:11