Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 18 3 2019 06 08 251 261 EN Huan Liu Department of Preventive Medicine, North Sichuan Medical College, Nanchong, Sichuan, China AND Department of Forensic Medicine, North Sichuan Medical College, Nanchong, Sichuan, China Yu Feng Department of Criminal Science and Technology, Chongqing Police College, Chongqing, China Wei Zhang Department of Forensic Medicine, North Sichuan Medical College, Nanchong, Sichuan, China Xiao-Dong Deng Department of Forensic Medicine, North Sichuan Medical College, Nanchong, Sichuan, China Ying Ma Department of Neurology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China Yun Liu Department of Forensic Medicine, North Sichuan Medical College, Nanchong, Sichuan, China 2018 04 05 2019 01 12 Growing evidence indicated conflicting results that Interleukin-18 (IL-18) promoter polymorphisms rs1946518 (A-607C), rs187238 (G-137C) and rs549908 (A-105C) were associated with asthma risk. The aim of this study is to comprehensively evaluate the IL-18 polymorphisms and asthma by a systematic review and meta-analysis. A total of 12 studies testing the association between these polymorphisms and asthma were examined (8 studies for A-607C, 8 studies for G-137C, and 4 studies for A-105C) in the update meta-analysis, up to Dec 30, 2017. Summary odds ratios (ORs) and 95% confidence intervals (CI) were used to estimate the strength of association between each polymorphism and asthma using fixed- and random-effects models when appropriate. Heterogeneity and publication bias were evaluated. The meta-analysis results indicated that any allele frequencies of the IL-18 polymorphisms (A-607C, G-137C and A-105C) was not associated with asthma risk (p>0.05). And no statistically significant association was observed between genotype frequencies of these polymorphisms and asthma under different genetic models (p>0.05). Subgroup analysis results were similar to the main analysis by ethnicity, sample size, genotyping methods, matching criteria and quality score. There was no evidence of publication bias. The present meta-analysis suggests that IL-18 polymorphisms (A-607C, G-137C and A-105C) were unlikely to be associated with asthma risk.   https://ijaai.tums.ac.ir/index.php/ijaai/article/view/1908 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/1908/1408