New study suggests childhood genes can predict adult obesity risk
An international study has found that a child’s genetic profile could accurately predict their future risk of living with obesity. Researchers say the findings could pave the way for earlier and more targeted prevention efforts – long before weight-related health issues take hold.
Led by scientists from the University of Copenhagen and University of Bristol, the study used genetic data from over five million people to develop a polygenic risk score (PGS), a tool that calculates an individual's genetic predisposition to obesity. Published in Nature Medicine, the research highlights the potential of genetic analysis in early life to inform strategies that help reduce future obesity rates.
The World Obesity Federation predicts that more than half of the global population will be living with overweight or obesity by 2035. While treatments such as medications, surgery and lifestyle interventions exist, they are not universally effective or accessible. The ability to identify at-risk individuals earlier could shift the focus to prevention.
“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,” said Assistant Professor Roelof Smit from the University of Copenhagen, the study’s lead author. “Intervening at this point could theoretically make a huge impact.”
The new PGS outperforms existing methods, explaining nearly 17 per cent of variation in body mass index (BMI) – double the predictive power of previous scores. It draws on data from global sources including the GIANT consortium and 23andMe, and was validated using BMI data from more than half a million people, including long-term tracking from the University of Bristol’s Children of the 90s study.
Dr Kaitlin Wade, Associate Professor in Epidemiology at the University of Bristol and co-author of the study, said: “Obesity is a major public health issue with complex causes, many of which start in childhood. By identifying those at higher risk earlier, we can help reduce future burden through more targeted and timely interventions.”
Importantly, the study also explored how genetics interact with lifestyle changes. Researchers found that individuals with higher genetic risk were more likely to benefit from weight loss interventions – but were also more likely to regain weight once those interventions stopped.
“Genetics is not destiny,” the researchers stress, rather, it provides a valuable tool for understanding who may benefit most from early support.
However, the researchers also highlight a key limitation, the PGS was more accurate in people with European ancestry than in those with African ancestry. This reinforces the need for future studies to include more diverse populations to improve the accuracy and equity of predictive tools.