An international team of researchers has developed a new test that can identify children at an increased genetic risk of becoming overweight at an early age, potentially giving parents more time to help their children develop healthy eating and exercise habits.
How the test works
The method is called a polygenic score (PGS), and it combines hundreds of thousands of genetic variations to predict the likelihood of a high body mass index (BMI) in the future.
"What makes this indicator so powerful is its ability to predict as early as five years of age whether a child is likely to be overweight as an adult, long before other factors influence their weight," explains genetic epidemiologist Roelof Smith from the University of Copenhagen.
The test was twice as accurate as previous similar methods. To create it, scientists used genetic data from more than 5.1 million people.
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In children aged 5 years, PGS explained 35% of the difference in BMI by age 18 years.
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In adults of European descent, the accuracy was 17.6%.
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In some groups, such as rural Ugandans, the accuracy was much lower — 2.2%.
This is due to the fact that the databases contain significantly more representatives of European populations, while African populations have higher genetic diversity and are less represented in studies.
The study also found that participants with a strong genetic predisposition to a high BMI lost more weight in the first year of weight loss programs, although they were more likely to regain it later, suggesting that even with a strong genetic predisposition, lifestyle and behavioral factors remain crucial.
"Our results refute the idea that genetics determines everything and is immutable," the authors note.
According to scientists, early identification of risk allows parents and doctors to more quickly implement preventive measures - healthy nutrition, physical activity, and other healthy habits.
"This new polygenic score significantly improves prediction and brings us closer to clinically useful genetic testing," adds Professor Ruth Loos of the University of Copenhagen.
