IL18 and Parkinson disease: We conducted logistic regression analyses of two functional variants [−819 T/C (rs1800872) and −592 A/C (rs1800871)] in the promoter region of IL-10 and one functional variant [−137 G/C (rs187238)] in the promoter region of IL-18 to assess their relationships with sporadic PD and PD-associated cognitive decline in a Han Chinese population.