Moreover, circulating Nrg4 was positively and independently associated with 25(OH)D, and was negatively with VPT (P < 0.01 or P < 0.05), but showed no associations with the prevalence of peripheral arterial disease, diabetic nephropathy, and diabetic retinopathy (all P > 0.05). The gene discussed is NRG4; the disease is diabetic retinopathy.