A new study published in the journal Nature Medicine examined how genetic changes on the Y chromosome are associated with the risk of type 2 diabetes in men in East Asia and Europe[1][2]. The research team analyzed data from 122,683 men from a Japanese biobank and 181,472 men from a British biobank[1]. They found that somatic loss of the Y chromosome (LOY)—an age-related genetic change—increases the risk of type 2 diabetes in Japanese men, especially those with lower polygenic risk scores[1][2]. Conversely, in European men, LOY was associated with a reduced risk of diabetes[1]. Using single cell analysis, researchers found that LOY accumulates in pancreatic β-cells, which may impair glucose metabolism[1]. The study also revealed that Y-chromosome haplogroup D, which is prevalent in the Japanese population, was associated with a reduced risk of type 2 diabetes[2]. The results show that including information about variations on the Y chromosome improves the prediction of type 2 diabetes risk in both sexes[1].