Association between interleukin-4 gene -590 c/t, -33 c/t, and 70-base-pair polymorphisms and periodontitis susceptibility: a meta-analysis.

BACKGROUND: Several studies have investigated the association between interleukin (IL)-4 gene -590 C/T, -33 C/T, or 70-base pair (70-bp) polymorphisms and periodontitis susceptibility but with conflicting results. Hence, a meta-analysis was conducted to explore whether these polymorphisms are associated with periodontitis susceptibility. METHODS: A comprehensive literature search was conducted of PubMed, Embase, Scopus, ScienceDirect, and Web of Science up to April 5, 2014. After the eligible studies were identified, data were extracted and quality-assessed before performing the meta-analysis. RESULTS: The meta-analysis included 23 eligible case-control studies from 11 articles involving 12 studies of the -590 C/T polymorphism (1,220 cases and 2,039 controls), five of the -33 C/T polymorphism (715 cases and 967 controls), and four of the 70-bp polymorphism (426 cases and 506 controls). The meta-analysis showed that none of these IL-4 gene polymorphisms were significantly associated with periodontitis susceptibility in all study participants. However, subgroup analysis showed that the IL-4 -590 T allele (odds ratio [OR] = 1.2, 95% confidence interval [CI] = 1.02 to 1.42, P = 0.03) and TT genotype (OR = 1.68, 95% CI = 1.05 to 2.67, P = 0.03) were associated with periodontitis in whites. CONCLUSIONS: Based on current evidence, the IL-4 -33 C/T and 70-bp polymorphisms were not associated with an increased risk of periodontitis. However, the IL-4 -590 T allele and TT genotype were associated with increased risk of periodontitis in whites.