GJA4 and diabetes mellitus: For the modifying effect of the Cx37 gene polymorphism, the uACR was inversely and strongly associated with HbA1c in CC homozygotes (p = 0.01) The ORI (Fig. 3b) was positively and strongly associated with age, diabetes duration, smoking, and pulse pressure (p = 0.002, p < 0.001, p = 0.004, and p < 0.001, respectively), and it was inversely and moderately associated with female sex and strongly associated with plasma vitamin D (p = 0.02 and p < 0.001., respectively).