Interleukin-1β (3953/4) C→T polymorphism increases the risk of chronic periodontitis in Asians: evidence from a meta-analysis of 20 case-control studies

INTRODUCTION: To investigate the association of the interleukin-1β (IL-1β) (3953/4) C→T polymorphism with chronic periodontitis (CP) in Asians. MATERIAL AND METHODS: Systematic searches of electronic databases and hand searching of references were performed, including PubMed, Embase, the Cochrane Library, and the Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations. Publication bias was tested by Egger's test. Sensitivity analysis was conducted by limiting the meta-analysis studies conforming to Hardy-Weinberg equilibrium (HWE). Data analyses were carried out using RevMan 6.0. RESULTS: A meta-analysis was performed on 20 published case-control studies, including 1,656 CP cases and 1,498 healthy controls. The pooled OR was 1.60 (95% CI = 1.02–2.52, p = 0.04) for the T allele carriers (TT + CT) compared with CC and 1.60 (95% CI = 1.06–2.42, p = 0.02) for T vs. C. Subgroup analysis by country revealed significant risks of CP among Indians carrying the T allele (TT vs. CC: OR = 3.88, 95% CI = 1.77–8.50, p = 0.0007). CONCLUSIONS: The analysis showed that IL-1β (3953/4) C→T polymorphism probably increases the risk of CP in Asians, and the IL-1β+3954 TT genotype may be associated with a strongly increased risk of CP in Indians, but not in Chinese.