The SPO11-C631T gene polymorphism and male infertility risk: a meta-analysis

Figures & data

Table 1. Main characteristics of studies included in the meta-analysis.

			Genotyping	Genotype (CC/CT/TT)
Authors	Year	Ethnicity	Method	Infertility	Control	HWE(p)
Zhang et al^18	2011	Chinese	PCR-RFLP	65/8/0	114/3/0	.888
Karimian et al^16	2015	Iranian	PCR-RFLP	100/0/0	99/1/0	.960
Ghalkhani et al^17	2014	Iranian	PCR-RFLP	100/12/1	49/1/0	.943
Han et al^20	2012	Chinese	PCR-RFLP	34/6/0	44/1/0	.940
Feng et al^19	2015	Chinese	PCR	189/27/0	195/3/0	.914

Table 2. Quality assessment for all the included studies.

First authors	Publishing year	Selection	Comparability	Exposure	Total
Zhang	2015	★★★	★	★★	6
Karimian	2015	★★★	★	★★	6
Ghalkhani	2014	★★	★	★★	5
Han	2013	★★★	★	★★	6
Feng	2012	★★★	★	★★	6

Figure 1. Flowchart showing the study selection.

Figure 2. Forest plot of the studies assessing the association between SPO11 C631T gene polymorphisms and male infertility (subgroup analyses for the Iranian and Chinese: allele model: T vs. C).

Figure 3. Forest plot of the studies assessing the association between SPO11 C631T gene polymorphisms and male infertility (subgroup analyses for the Iranian and Chinese: codominant model: CT vs. CC).

Figure 4. Forest plot of the studies assessing the association between SPO11 C631T gene polymorphisms and male infertility (subgroup analyses for the Iranian and Chinese: dominant model: TT + CT vs. CC).

Figure 5. Funnel plot of the studies assessing the association between SPO11 C631Tgene polymorphisms and male infertility (allele model: T vs. C).

Figure 6. Sensitivity analysis diagram for each study used to assess the relative risk estimates for the SPO11 C631T gene polymorphism and male infertility in all the included studies (allelic model: T allele vs. C allele).

Figure 7. Sensitivity analysis diagram for each study used to assess the relative risk estimates for the SPO11 C631T gene polymorphism and male infertility in all the included studies (codominant model: CT vs. CC).

Table 3. Publication bias test for SPO11 C631T polymorphism.

	Egger’s test			Begg’s test
Comparisons	Coefficient	p Values	95%CI	p Values
T vs. C	0.006	0.841	−0.104 to 0.116	.734
CT vs. CC	0.010	0.820	−0.157 to 0.177	1.000
CT + TT vs. CC	0.008	0.851	−0.160 to 0.176	1.000

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