GPNMB and Parkinson disease: Among these nine proteins, the abundance of six proteins, ARSA (OR = 2.177,p = 7.53e‐04), EHBP1 (OR = 3.739, p = 1.27e‐02), FCGR2A (OR = 1.059, p = 4.37e‐05), GGH (OR = 1.167, p = 2.81e‐02), GPNMB (OR = 1.503, p = 1.79e‐07), and HDHD2 (OR = 1.230, p = 1.64e‐02), was significantly associated with an elevated risk of PD onset, whereas the abundance of DNAJB4 (OR = 0.701, p = 2.54e‐03), HAVCR2 (OR = 0.905, p = 5.55e‐03), and PDCD1LG2 (OR = 0.852, p = 2.44e‐02) was associated with a reduced risk.