Over the last few years, a growing number of toxicological studies have also suggested an association between PM2.5 and diabetes through an inflammatory pathway leading to endothelial dysfunction, immune response alterations in visceral adipose tissues, and endoplasmic reticulum stress leading to alterations in insulin transduction, insulin sensitivity, and glucose metabolism [19,20,21,22,23]. This evidence concerns the gene INS and endothelial dysfunction.