Association between interleukin-1α C(-889)T polymorphism and Alzheimer's disease: a meta-analysis including 12,817 subjects.

Epidemiological studies have evaluated the association between interleukin-1 (IL-1)α C(-889)T polymorphism and Alzheimer's disease (AD), but the results remain inconclusive. This meta-analysis was, therefore, designed to clarify these controversies. Systematic searches of electronic databases Embase, PubMed, and Web of Science as well as hand searching of the references of identified articles and the meeting abstracts were performed. Statistical analyses were performed using software Review Manager (Version 5.1.2) and Stata (Version 11.0). The pooled odds ratios (ORs) with 95 % confidence intervals (95 % CIs) were calculated. A total of 28 publications including 29 studies were involved. There was a significant association between IL-1α C(-889)T polymorphism and AD (for T allele vs. C allele: OR = 1.14, 95 % CI = 1.07-1.21; for T/T vs. C/C: OR = 1.39, 95 % CI = 1.18-1.63; for dominant model: OR = 1.13, 95 % CI = 1.04-1.22; and for recessive model: OR = 1.39, 95 % CI = 1.20-1.60). Significant association was found for Asians, Caucasians, and early-onset Alzheimer's disease (EOAD) but for late-onset Alzheimer's disease (LOAD). This meta-analysis indicates that there is a significant association between IL-1α C(-889)T polymorphism and AD as well as EOAD.