Quantitative Assessment of the Associations Between Interleukin‐8 Polymorphisms and Periodontitis Susceptibility

Background: This review assesses the associations of interleukin‐8 gene (IL‐8) ?251A/T (rs4073) and ?845T/C (rs2227532) polymorphisms with susceptibility to periodontitis. Methods: Several electronic databases were searched for eligible articles. Twelve studies involving 2,233 cases and 2,655 controls were retrieved and analyzed. Odds ratios (ORs) along with 95% confidence intervals (CIs) were calculated to assess the strength of relationship between the IL‐8 polymorphisms and periodontitis risk. Results: No significant association was found for IL‐8 ?251A/T polymorphism with periodontitis in the overall analysis and stratification by periodontitis type and smoking status. Subgroup analysis by ethnicity revealed that ?251A/T T allele and TT genotype were associated with decreased risk of periodontitis in a Brazilian mixed population (T allele versus A allele: OR 0.80, 95% CI 0.68 to 0.94, P_{heterogeneity} = 0.30; TT versus AA: OR 0.65, 95% CI 0.46 to 0.93, P_{heterogeneity} = 0.39; TT versus AA/AT: OR 0.58, 95% CI 0.35 to 0.98, P_{heterogeneity} = 0.01). In addition, ?251A/T T allele was associated with increased periodontitis risk in Asians. Pooled estimates showed that the ?845T/C polymorphism was associated with periodontitis susceptibility in overall analysis and the chronic periodontitis subgroup. In addition, marginal associations were observed between ?845T/C polymorphism and periodontitis in a Brazilian mixed population. Moreover, this association was also confirmed to be significant in Brazilian non‐smokers. Conclusion: This meta‐analysis indicated that both IL‐8 ?251A/T and ?845T/C polymorphisms may be involved in the development of periodontitis in a Brazilian mixed population, whereas the ?251A/T allele T appeared to be a risk factor for periodontitis in Asians.