Could BMI and Obesity Risk Be Genetically Destined?

Doctors will soon be able to accurately and efficiently predict a person’s body mass index, obesity risk, and overall mortality risk through a simple genetic test.  According to a new study conducted by a team of researchers from Harvard University and MIT’s Broad Institute, genetics at birth may actually determine these traits later in life.

The scientists took the polygenic score—a collection of genetic factors—from 306,000 people to find these relationships and shared traits. 

Study senior coauthor Sekar Kathiresan explains “We’ve had evidence for a long time that obesity is affected by genetics. What this really adds is the ability to distill the risk from the genome into a simple number for each person and look at that number in relation to the rest of the population.” 

The report indicates that every human genome—which is a matrix of 2 million genetic variations—can contribute to what amounts to be a “scorecard” that quantifies the potential for obesity.  While we still do not know what each of these potential variations do (or tell us), the certainty rests in that this research team managed to identify a near 30-pound difference between people with the highest and lowest scores. 

The cardiologist and geneticist from Massachusetts General Hospital goes on tos ay, “Obesity risk from genes can now be distilled into a single number for each person,” essentially as easy as measuring cholesterol. 

In the report, the study authors write “Despite this the strength of these associations, polygenic susceptibility to obesity is not deterministic. Among those in the top decile of the GPS [genome-wide polygenic score], 83 percent were overweight or obese, but 17 percent had a BMI within a normal range, and 0.2 percent were underweight.”

Scripps Research Translational Institute’s Eric Topol explains that this risk score can be applied as a preventative measure, which is particularly useful when you consider that the obesity rate in America is near 40 percent. He says, “People will have knowledge about their particular risk, and that would be a foundation for actionable efforts for prevention.”

All of this is important, of course, because obesity is not just about being dangerously overweight.  Obesity—as a health condition—immediately increases risk for heart disease and diabetes, which can also increase risk for things like Parkinson’s disease. 

The results of this study have been published in the medical journal Cell.