Interleukin-8 gene polymorphism –251T>A contributes to Alzheimer's disease susceptibility

BACKGROUND: Published association studies have investigated the correlation between interleukin-8 (IL-8) gene polymorphism –251T>A and susceptibility to Alzheimer's disease (AD); however, the results are conflicting. Thus, we conducted the meta-analysis to reassess the effect of IL-8 gene –251T>A variant on the risk of AD. METHODS: Relevant studies regarding this association were electronically searched and identified from the PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and the Chinese Biomedicine Database. The odds ratios (ORs) with the corresponding 95% confidence intervals (95% CIs) were pooled to calculate the strength of this association. RESULTS: Nine studies with a total of 1406 cases and 2152 controls were included in the meta-analysis. Overall, a significant association of IL-8 gene –251T>A polymorphism with increased risk of AD was observed in several genetic models (allele, A vs T: OR=1.32, 95%CI=1.16-1.50; homozygous, AA vs TT: OR=1.70, 95%CI=1.21–2.21; heterozygous, TA vs TT: OR=1.37, 95%CI=1.12–1.69; recessive, AA vs TA+TT: OR=1.40, 95%CI=1.12–1.75). Similarly, such association was also revealed both in Asian and European populations in the subgroup analysis by ethnicity. CONCLUSION: The current study suggested that IL-8 gene polymorphism –251T>A may contribute to the susceptibility to AD.