INS and Insulin resistance: Moreover, other data suggested that the odds of having insulin resistance was significantly greater for subjects in the lowest quartile of 25(OH)D compared to the other quartiles combined, likely by modulation of several key pathways affecting glucose metabolism (e.g., increasing proinflammatory cytokines and oxidative stress affecting insulin signaling and epigenetic regulation of gene expression, as well as RAAS) [28,29,30,31].