Flow chart depicting the selection of eligible studies during the meta-analysis.

<p>Flow chart depicting the selection of eligible studies during the meta-analysis.</p

Association between polymorphisms of heat-shock protein 70 genes and noise-induced hearing loss: A meta-analysis

<div><p>Background</p><p>Recent studies have evaluated the associations between polymorphisms of the heat-shock protein 70 (HSP70) encoding genes and noise-induced hearing loss (NIHL). However, the conclusions of these studies are conflicting. The objective of this meta-analysis was to clarify the association between all known polymorphisms of HSP70 genetic loci and susceptibility to NIHL, based on existing reports.</p><p>Methods</p><p>We conducted a meta-analysis of the association between Hsp70 polymorphisms (<b>rs1043618</b>, <b>rs1061581</b>, <b>rs2075800</b>, <b>rs2227956</b>, and <b>rs2763979</b>) and NIHL risk in both Chinese and Caucasian males. All statistical analysis was done with was conducted using the “meta” package (version 4.6–0) of R version 3.3.2 and RStudio version 1.0.44. Online databases were searched for eligible case-control studies on February 13, 2017. The odds ratio (OR), 95% confidence interval (CI), and P value were calculated using Mantel-Haenszel statistics under a random- or fixed-effect model.</p><p>Results</p><p>A total of five studies, reported via four articles from online databases, were included in our meta-analysis. For <b>rs1061581</b> (from three studies), a significant association was detected in the allele model, homozygote model, and dominant model (G versus A: OR (95% CI) = 1.32(1.05–1.67), GG versus AA: OR (95% CI) = 1.93(1.1–3.36), GG + AG versus AA: OR (95% CI) = 1.45(1.05–2.02)), but not in the heterozygote model or the recessive model. For <b>rs1043618</b> (from five studies), <b>rs2075800</b> (from two studies), <b>rs2227956</b> (from four studies), <b>rs2763979</b> (from two studies), no significant association was found for any genetic model. After subgroup analyses by ethnicity, significant associations were observed for the allele model, heterozygote model, and dominant model for <b>rs1061581</b> and any genetic model for <b>rs2227956</b> in Caucasians.</p><p>Conclusions</p><p>The <b>rs1043618</b>, <b>rs2075800</b>, and <b>rs2763979</b> polymorphisms were not found to be associated with susceptibility to NIHL; however, the <b>rs1061581</b> and <b>rs2227956</b> polymorphisms were significantly associated with NIHL in Caucasian males.</p></div

Begg's funnel plot of the association between five single nucleotide polymorphisms (SNPs) and noise-induced hearing loss (NIHL) in the allele model.

<p>A: for rs1043618; B: for rs1061581; C: for rs2075800; D: for rs2227956; E: for rs2763979.</p

Summary of pooled ORs in the meta-analysis.

<p>Summary of pooled ORs in the meta-analysis.</p

Forest plot of the association between polymorphism rs2227956 and noise-induced hearing loss (NIHL) (Allele model: C versus T).

<p>Forest plot of the association between polymorphism rs2227956 and noise-induced hearing loss (NIHL) (Allele model: C versus T).</p

Forest plot of association between polymorphism rs2075800 and noise-induced hearing loss (NIHL) (Allele model: T versus C).

<p>Forest plot of association between polymorphism rs2075800 and noise-induced hearing loss (NIHL) (Allele model: T versus C).</p

Begg’s funnel plot and Egger’s test of the meta-analysis.

<p>Begg’s funnel plot and Egger’s test of the meta-analysis.</p

Forest plot of the association between polymorphism rs1043618 and noise-induced hearing loss (NIHL) (Allele model: C versus G).

<p>Forest plot of the association between polymorphism rs1043618 and noise-induced hearing loss (NIHL) (Allele model: C versus G).</p

Forest plot of the association between polymorphism e rs2763979 and noise-induced hearing loss (NIHL) (allele model: T versus C).

<p>Forest plot of the association between polymorphism e rs2763979 and noise-induced hearing loss (NIHL) (allele model: T versus C).</p

Forest plot of the association between polymorphism rs1061581 and noise-induced hearing loss (NIHL) (Allele model: G versus A).

<p>Forest plot of the association between polymorphism rs1061581 and noise-induced hearing loss (NIHL) (Allele model: G versus A).</p