They determined more genetic loci that affect GLUT4, which apparently is a protein that transports glucose from the outside of cells to the inside. See Wikipedia:
If you have the “wrong” genetics, you have less GLUT4 on the outside of fat/muscle cells, which means your cells take in less glucose, putting you on the path to diabetes.
(Though I should note the Wiki article states that too much GLUT4 in fat cells…causes MORE fat to be accumulated. Confusing.)
If I understand correctly, I think it makes sense. As less GLUT4 led to less blood glucose to be transported from blood into the fat or muscle cells inner part. Too much GLUT4 will lead to more blood glucose to be transported from blood into the fat or muscle cells inner part, and then the abundant glucose transported to the cells are transformed to be fat accumulated? This is my understanding, probably, who knows
I was hoping to see the actual article, to see if they indicated which genetic loci they were using, so I could go into my own genetics to see what I have. Alas, it’s behind a paywall.