TNF-alpha G308A Polymorphism and the Susceptibility to Alzheimer's Disease: An Updated Meta-analysis

Background and Aims. Tumor necrosis factor (TNF)-alpha G308A polymorphism has been reported in the association with susceptibility to Alzheimer's disease (AD); however, results have been contradictory. We conducted an updated meta-analysis to evaluate the role of TNF-alpha G308A in the occurrence of AD. Methods. Relevant articles were retrieved from online databases. The combined odds ratio, odds ratio in different genetic models, and the related 95% confidence intervals were calculated. Publication bias and homogeneity among individual studies were estimated. Subgroup analyses and sensitivity analyses were also performed. Results. In overall analyses, no risk of AD was associated with TNF-alpha G308A under different genetic models. However, in the subgroup analyses, a significant association between TNF-alpha G308A and AD risk was observed in Chinese. In addition, a significant protective effect of TNF-alpha -308A was found in the occurrence of AD among North European populations under a dominant model. Conclusions. The result of this meta-analysis suggests that TNF-alpha G308A polymorphism may be associated with the increased risk of AD in Chinese and decreased risk of AD in northern European populations. (C) 2015 IMSS. Published by Elsevier Inc.