Parkinson's disease is the second most common neurodegenerative disorders after Alzheimer's disease in the elderly. Abundant evidence showed that proinflammatory factors were involved in the pathogenesis of sporadic Parkinson's disease (SPD). Interleukin-1 (IL-1) is a cytokine that plays an important role in neurodegenerative disease. Previous association studies between genetic polymorphisms of IL-1 alpha and PD have showed conflicting results and no such study was done in Chinese. We recruited 533 SPD patients and 530 controls in Chinese Han population to investigate the association of IL-1(x C-899T allele and risk for PD. Real-time PCR was used to detect the polymorphism, and multiple logistic regression, Chi square test and survival analysis were performed to explore the association. The distribution of IL-1 alpha alleles was significantly different between the cases and controls, and the T allele was associated with a reduced risk of PD (OR: 0.72, 95%Cl: 0.54-0.97, rho = 0.033). However, survival analysis showed that the T allele did not delay the onset age of PD (T allele vs. non-T allele log rank: chi(2) = 0.14, p = 0.70). Our data suggest that the T allele carriers have less inclination to have PD in Chinese Han population. (C) 2008 Elsevier Ireland Ltd. All rights reserved.