Meta-analysis Of The Relationship Between Thyroid Nodules And Iodine Intake

Objective:To study and analyze the correlation between iodine deficiency or excess and Thyroid Nodule(TN)evaluated with Median urinary iodine(MUI),to provide evidence-based medical evidence for etiological study,clinical treatment and follow-up,and to provide basis for the diagnosis and treatment of Thyroid nodule disease.Methods:Comprehensive retrieval of Pub Med,Embase,The Cochrane library,Web of Science,CNKI,Wan Fang,VIP and other databases.The retrieval time limit is controlled within a certain range,that is,from the establishment of the database to November 2020.Literature on iodine intake and thyroid nodule was searched.The literature was included and excluded in strict accordance with the established criteria,and quality evaluation and data extraction were conducted for the included literature.At the same time,meta-analysis was also performed using Review Manager 5.3 software.The incidence of thyroid nodules and thyroid cancer was analyzed by odds ratio(OR)and 95%confidence interval(95%CI).The appropriate effect model was selected according to Q test and I~2value and the heterogeneity was evaluated.When I~2is less than 50%,it is considered that there is little heterogeneity among the results,and the combined comprehensive effect can be calculated by using the fixed effect model.When I~2is greater than 50%,it is considered that there is great heterogeneity among the results.In this case,the combined comprehensive effect can be calculated by using the random-effects model,and the source of heterogeneity should be found through subgroup analysis and sensitivity analysis.Forest plots were used to combine outcome indicators,and funnel plots were used to evaluate whether there was publication bias in theincluded literatures.In order to obtain quantitative results,Egger test was conducted with Stata13.0 software.Results:(1)A total of 8 literatures on thyroid nodules(benign and malignant without distinction)and iodine intake were included in this meta-analysis,including 926 thyroid nodule cases in the iodine excess group and 1863 thyroid nodule cases in the iodine deficiency group.The combined effect size OR is equal to 0.66,95%CI(0.60,0.73).(2)A total of5 literatures on malignant thyroid nodules,thyroid cancer and iodine intake were included in this meta-analysis,including 460 cases of malignant nodules in the iodine excess group and 242 cases in the iodine deficiency group.The combined effect size OR is equal to 0.90,95%CI(0.71,1.14).Conclusions:(1)Compared with the control group(median urinary iodine is less than 100ug/L),the case group(median urinary iodine is greater than or equal to 300ug/L)was less prone to thyroid nodular disease.(2)There was no significant correlation between inadequate iodine intake(median urinary iodine is less than 100ug/L)and excessive iodine intake(median urinary iodine is greater than or equal to 300ug/L)and the incidence of thyroid cancer.