A genetic scorecard may help experts determine whether newborn infants are at risk of developing obesity.
Scientists from the Broad Institute and Massachusetts General Hospital have developed a genetic test that they believe can predict the risk of severe obesity in babies.
If successful, the possibility of administering a routine test could help destimagtize obesity while urging those who are at risk to focus on getting healthy.
Genetic Test Could Predict Obesity Risk In Newborns
The team of researchers analyzed data from the largest genome wide association study. Compiled by another research team in 2015, the GWAS aimed to scan an entire genome for specific gene variants linked with a certain trait or condition.
Authors of the new study then examined more than 2 million gene variants among 300,000 people, whose ages ranged from newborns to middle-aged adults.
Using a computer algorithm, researchers crunched the numbers to produce a "polygenic" obesity risk score that then predicted a person's BMI score based on the influence of multiple genes.
Results of the GWAS prove that some people gain weight because their genes are more susceptible than other people to develop obesity.
In fact, 10 percent of study participants with the highest risk scores were 29 pounds or 13 kilograms on average heavier than the group in the lowest decile.
Those with high scores were 25 times more likely to develop severe obesity compared to the bottom 10 percent, researchers said.
However, the GWAS also revealed that there was no link between a chubby baby growing old into a chubby adult. The correlation between genetic risk and weight is apparent when the baby turns into a toddler.
Amit Khera, the first author of the study, said they expected to see a link between weight outcomes and genetic score. Khera said they were surprised to see the impact of genetic predisposition to emerge by the time the children enroll in preschool.
Furthermore, past studies that examined genetic causes of obesity often focused on single genetic mutations, said Khera. On an individual basis, Khera said these mutations are uncommon. In fact, the cumulative effect of many genetic variants usually translates to an increased risk of severe obesity.
Details of the new study are published in the journal Cell.
Some Scientists Are Skeptical About A Genetic Scorecard
Other experts are skeptical about the results of the study. Genetic epidemiologist Ruth Loos from Icahn School of Medicine at Mount Sinai in New York said genes are responsible for people's obesity risk, but lifestyle factors such as exercise and diet are equally important.
"Even if you have a genetic score that perfectly captures that 50 percent of genetics, you still will not be able to predict anyone's future risk of obesity," said Loos.
Epidemiologist Cecile Janssens from Emory University in Atlanta meanwhile suggested that instead of focusing on people who are susceptible to obesity, perhaps it is better to predict whether people who are overweight might become obese. This can help overweight people prevent that transition to obesity, said Janssens.
Another issue pointed out is that the study's findings do not fully address how it could affect patient care. Khera said that this is something they are planning to look into in future research.
He further emphasized that determining that severe obesity has a strong genetic basis helps in fighting stigma against obese people. He added that knowing whether you're at risk for obesity at a young age could encourage lifestyle interventions and earlier treatment.
Since DNA does not mean destiny, the key is to empower people to prevent the onset of severe obesity, said Khera.
Photo: Jessica Merz | Flickr