Association between interleukin-4 C589T polymorphism and asthma in Iraq: Ameta-analysis

Background: Asthma is a common disease with a complex risk architecture involving both genetic and environmental factors. Several studies have identified an association between interleukin (IL)-4 C-589T and asthma risk; however, the results remain inconclusive. Aims to identify the effect of IL-4 C589T polymorphisms on asthma susceptibility in Iraq. Material and methods PubMed, Web of Science, Scopus, and Google Scholar databases were searched for only case-control studies published on Iraqi asthmatic. The methodological quality assessment of the included studies was performed based on the Newcastle-Ottawa Quality Scale (NOS). Based on the heterogeneity, we conducted a meta-analysis using random-effect models. Pooled odds ratios (ORs) with a 95% confidence interval (CI) were calculated using the allele (C vs. T), homozygous (CC vs. TT), heterozygous (CT vs. TT), dominant (CC þ CT vs. TT), and recessive (CC vs. CT þ TT) genetic models to assess the strength of the relationship between IL-4 C589T polymorphism and asthma risk. In addition, the stability of our analysis was evaluated by heterogeneity, sensitivity, and study design, and publication bias analysis. Result We included 5 case-control studies with a total of 359 cases and 245 controls. All genetic models showed a higher risk of asthma, the overall analyses were a highly statistically significant. There was moderate to high heterogeneity among the genetic models. However, sensitivity analysis revealed highly significant differences in the pooled odds ratios of the rs2243250 polymorphism between asthmatic patients and control groups. Conclusion The meta-analysis identified a significant association between the IL-4 C-589T polymorphism and asthma. However, the substantial result variability indicates the need for well-designed case-control studies with a large population to more accurately estimate this association.