The etiology of sporadic Parkinson's disease (PD) is not well established. Interleukin-18 (IL-18), a member of pro-inflammatory cytokines, might influence the risk of sporadic PD occurrence and development. In this study, two DNA polymorphisms at interleukin (IL)-18 promoter, -607C/A (rs1946518) and -137G/C (rs187238), were examined in sporadic PD patients in a Han Chinese population with 290 sporadic PD patients and 200 healthy controls. Direct sequencing was performed in 10% of the samples to validate the genotyping results. The results revealed that for -607C/A polymorphisms, there were significant differences in genotype distribution between PD and control in the total sample (P=0.017) and between LOPD and healthy-matched controls subgroup (P=0.011). For -137G/C polymorphisms, there were no significant differences in genotype distribution and gender and age-related differences between PD and control in the total sample (P=0.610). Results in this study revealed that the IL-18 607C/A polymorphism is a risk factor for sporadic LOPD in Han Chinese population, while IL-18 137G/C polymorphism is not a risk factor for sporadic PD in the Han Chinese population. (C) 2011 Elsevier B.V. All rights reserved.