<b>Results:</b> PD patients exhibited higher fasting insulin (10.7 ± 5.2 vs. 8.0 ± 4.4 μIU/mL; <i>p</i> = 0.020) and HOMA-IR (2.63 ± 1.40 vs. 1.89 ± 1.21; <i>p</i> = 0.014) compared to controls. This evidence concerns the gene INS and Parkinson disease.