ObjectiveTo explore the association between single nucleotide polymorphism (SNP) in the X-ray cross complementary repair gene-1 (XRCC1) rs1799782 locus and thyroid cancer.MethodsStudies investigating the association between SNP in the XRCC1 gene and thyroid cancer susceptibility were retrieved from the PubMed, Embase, Web of Science, CNKI (Chinese National Knowledge Infrastructure), Wanfang, and CBM (China Biology Medicine) databases (published date up to February 15, 2021). Eligible studies were screened according to inclusion/exclusion criteria and principles of quality evaluation. Meta-analysis was performed using Stata 14.0 software. Odds ratios with their corresponding 95% confidence intervals (95%CI) were pooled to assess the association between SNP in the XRCC1 gene rs1799782 locus and thyroid cancer susceptibility.ResultsTwelve articles were eligible for this meta-analysis. Meta-analysis results were shown as follows: No significant association was found between XRCC1 rs1799782 polymorphism and thyroid cancer in overall population [Dominant model: CT+TT vs CC, OR=1.07, 95%CI (0.84, 1.36). Recessive model: TT vs CT+CC, OR=1.48, 95%CI (0.95, 2.31). Allelic model: T vs C, OR=1.15, 95%CI (0.93, 1.43). Codominant model: TT vs CC: OR=1.44, 95%CI (0.83, 2.53); CT vs CC, OR=1.02, 95%CI (0.82, 1.28); TT vs CT, OR=1.40, 95%CI (0.98, 1.99)]. rs1799782 polymorphism was significantly associated with the risk of thyroid cancer in Chinese population [Dominant model: CT+TT vs CC, OR=1.38, 95%CI (1.11, 1.71). Recessive model : TT vs CT+CC, OR=1.97, 95%CI (1.55, 2.50); Allelic model: T vs C, OR=1.40, 95%CI (1.16, 1.68). Codominant model: TT vs CC, OR=2.12, 95%CI (1.66, 2.71); CT vs CC, OR=1.26, 95%CI (1.09, 1.47); TT vs CT, OR=1.70, 95%CI (1.31, 2.21)]. rs1799782 polymorphism was significantly associated with the risk of thyroid cancer in Asian population [Dominant model: CT+TT vs CC, OR=0.64, 95%CI (0.49, 0.83). Codominant model: TT vs CC: OR=0.50, 95%CI (0.33, 0.74); CT vs CC, OR=0.65, 95%CI (0.49, 0.86)].ConclusionsThere is no significant correlation between XRCC1 rs1799782 polymorphism and the risk of thyroid cancer in general population. The XRCC1 rs1799782 polymorphism may be associated with an increased thyroid cancer risk among Chinese, and a tendency for decreased thyroid cancer risk among Asians (Chinese excluded). The XRCC1 rs1799782 polymorphism is not associated with thyroid cancer susceptibility among Caucasians under all genetic models.