Abstract: OBJECTIVE： To investigate involvement of serum selenium and urine iodine concentrations (UIC) with thyroid cancer through meta-analysis. METHODS： Systematic search was conducted through PubMed，Web of Science，Wanfang Database and CNKI for relevant publications up to November 2023. Meta-analyses were performed using Review Manager 5.4.1 and Stata 17. RESULTS： A total of 18 reports including 22 case-control studies with 6 457 participants were included. Pooled analysis showed that the serum selenium level of thyroid cancer patients was lower than that of healthy controls [SMD=-1.46，95%CI=(-2.21，-0.72)，P=0.001]. Compared with the healthy control group，excessive iodine intake (UIC≥300 μg/L) was positively correlated with the occurrence of thyroid cancer [OR=2.68，95% CI=(1.40，5.12)，P=0.003]，and the appropriate iodine intake (100≤UIC<200 μg/L) was negatively correlated with the occurrence of thyroid cancer [OR=0.47，95%CI=(0.29，0.76)，P=0.002]，and insufficient iodine intake (UIC<100 μg/L) [OR=0.62，95%CI=(0.35，1.09)，P=0.10] and minor iodine overdose (200≤UIC<300 μg/L) [OR=0.81，95%CI=(0.50，1.32)，P=0.40] were not statistically significant with the occurrence of thyroid cancer. CONCLUSION： This meta-analysis indicates that decreased serum selenium levels may elevate the risk of developing thyroid cancer，whereas excessive iodine intake could serve as a potential risk factor for thyroid cancer. Conversely，moderate iodine intake may confer protection against thyroid cancer.

Key words: thyroid cancer, meta-analysis, serum selenium, urine iodine concentration