Obesity risk can now be predicted at age 5, Hyderabad scientists contribute to global study
Hyderabad: Obesity is a growing public health concern worldwide, affecting individuals across all age groups, from children to adults. Beyond its social and psychological effects, obesity significantly increases the risk of non-communicable diseases such as diabetes, cardiovascular disease, reproductive disorders, bone health issues, and several types of cancer. The World Obesity Federation predicts that by 2035, more than half of the global population will be overweight or obese.
In a major international effort to address this crisis, a global team of 600 researchers from 500 institutions has developed a new genetic test that can predict a person’s risk of developing obesity in adulthood, as early as age five. The study, published in Nature Medicine, draws on the most extensive and diverse genetic dataset assembled to date.
The team used data from over five million individuals, sourced from the GIANT consortium and consumer DNA company 23andMe. The researchers created a polygenic risk score (PRS) that can identify children at a higher genetic risk for obesity long before symptoms appear. This new test is twice as effective as previous models at predicting long-term obesity risk.
“What makes the score so powerful is its ability to predict, around the age of five, whether a child is likely to develop obesity in adulthood, well before other risk factors start to shape their weight. Intervening at this point can have a huge impact,” said Assistant Professor Roelof Smit of the NNF Center for Basic Metabolic Research at the University of Copenhagen, and lead author of the study.
India’s Critical Role in the Research
India, where obesity is increasingly linked to rising rates of diabetes, hypertension, and heart disease, played a key role in the research. Notably, Indians tend to have a different pattern of obesity, with a higher prevalence of abdominal (central) fat compared to populations in Europe.
Researchers at the CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB) in Hyderabad, led by Dr. Giriraj Ratan Chandak, contributed valuable long-term genomic data to the study. The data included individuals with diabetes and those with normal glucose levels, followed for nearly two decades, offering a rare opportunity to explore the genetic basis of obesity in the Indian population.
Based on this data, the team identified several obesity-linked genetic variations specific to Indians. These were used to develop a population-specific PRS, effectively creating a “virtual individual” to model genetic risk for obesity in South Asians. This inclusion ensures that the findings are more applicable to Indian and South Asian populations, which have historically been underrepresented in genetic studies.
Dr. Giriraj Ratan Chandak’s earlier research had already shown that the genetic causes of non-communicable diseases differ significantly between Europeans and Indians. “The observations made from this study are similar to the earlier results on height, where genetic variants identified in Europeans predicted lower risk in Indians,” said Dr. Chandak. “Environment-related modifications of genes play a larger role. It looks like lifestyle, diet, and nutrition might be playing an equal or more important role in predicting obesity in Indians. So, for Indians, lifestyle solutions or specific nutrient supplementation in the background of genetic risk might yield better results.”
Genetics Is Not Destiny
The researchers also examined how genetic risk interacts with lifestyle interventions. Interestingly, individuals with a high genetic risk responded more effectively to lifestyle changes such as diet and exercise. However, they were also more likely to regain weight after the interventions ended.
The study further confirmed that ancestry continues to influence how well genetic scores predict obesity. While this PRS showed greater accuracy than any previous tool, it was still more effective in individuals of European ancestry than in those of other backgrounds, including South Asians. Many gene variants associated with obesity in Europeans do not function the same way in Indian populations, showing differences in how obesity manifests across ethnic groups.
These findings suggest that while genetic tools can guide early prevention, they must be adapted to account for ancestry and regional patterns of disease. For India and similar populations, combining genetic risk assessment with targeted lifestyle and dietary interventions may offer the most effective strategy to reduce the growing burden of obesity.