Pertaining to PD, our findings indicated a singular cytokine, Interleukin‐17A (OR = 1.2852, p = 0.0145), as having a positive causal effect on the risk of developing the disease, with a contrasting negative causal effect observed for five cytokines, which include Fibroblast growth factor 21 (OR = 0.8169, p = 0.0387), Interleukin‐12 subunit beta (OR = 0.8987, p = 0.0333), Neurturin (OR = 0.7346, p = 0.0049), Transforming growth factor‐alpha (OR = 0.8254, p = 0.0478) and Tumour necrosis factor receptor superfamily member 9 (OR = 0.8451, p = 0.0105) (Table S1—Data S1). Here, FGF21 is linked to Parkinson disease.