A new genetic scoring tool may help identify children at risk of adult obesity, offering earlier opportunities for prevention before other risk factors develop.
Researchers developed a system that analyses thousands of genetic variations to produce a polygenic risk score (PGS) – a measure combining the effects of multiple genes linked to weight.
Using data from over five million people, teams from the Universities of Copenhagen and Bristol created a score that was twice as effective as earlier models at predicting obesity risk.
The score explained 17 per cent of variation in body mass index (BMI) between individuals. It showed consistent links to BMI from before age five into adulthood, suggesting a potential window for early intervention.
Assistant professor Roelof Smit at the University of Copenhagen is lead author of the research.
Smit said: “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. Intervening at this point could theoretically make a huge impact.”
The World Obesity Federation expects more than half the global population to be overweight or obese by 2035.
Current approaches such as lifestyle change, surgery and medication are not universally available or always effective.
The research team tested the score using datasets of over 500,000 people, including long-term BMI data from the Children of the 90s study.
The analysis combined genetic data from the Genetic Investigation of ANthropometric Traits (GIANT) consortium and DNA testing company 23andMe.
Dr Kaitlin Wade, associate professor in epidemiology at the University of Bristol, said: “Obesity is a major public health issue, with many factors contributing to its development, including genetics, environment, lifestyle and behaviour.
“These factors likely vary across a person’s life, and we believe that some of these originate in childhood.
“We were delighted to contribute data from the Children of the 90s study to this exceptional and insightful research into the genetic architecture of obesity.
“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.”
The study also explored how genetic risk affects responses to weight loss interventions.
People with higher genetic scores responded more strongly to diet and exercise but tended to regain weight more quickly once the programmes ended.
Despite using one of the largest and most diverse genetic datasets to date, the PGS performed better in people with European ancestry than in those with African ancestry.
Researchers said this underlines the need for more inclusive genetic studies.
While the score may help target prevention, the team emphasised that genetics is not destiny – a high risk score does not mean someone will definitely develop obesity.
