Correlation Between FT3 And Gonadal Function In Men With Normal Thyroid Function

Objective:Through the analysis of serum free Triiodothyronine(FT3),sex hormone and gonadal function in 1237 male inpatients in Dalian area,the difference of sex hormone level between male normal gonadal function group and male hypogonadism group was compared,the relationship between FT3 and the change of male gonadal function was studied,and the effect of FT3 on male gonadal function was discussed.Methods: Using the Yiduyun electronic medical record retrieval system,we collected1237 male patients who were hospitalized in Dalian Central Hospital from January 1,2010 to January 1,2021,and whose thyroid function was normal with or without positive thyroid antibodies,and who were tested for Thyroid hormones and gonadal hormone at the same time.Using the Yiduyun electronic medical record retrieval system,we collected the patient’s past disease history,medication history and other personal history;Thyroid-stimulating hormone,serum free triiodothyronine,serum free Thyroxine,Thyroid peroxidase antibody,thyroglobulin antibody,follicle stimulating hormone,Luteinizing hormone,estradiol,progesterone,testosterone,Prolactin,total cholesterol,triglyceride,low-density lipoprotein cholesterol,High-density lipoprotein cholesterol,blood uric acid,blood creatinine,alanine aminotransferase Laboratory indicators such as Asparagus cochinchinensis aminotransferase.Referring to the previous literature on the correlation between thyroid and metabolic syndrome and the fact that FT3 is the main intracellular active form,the male FT3 level was divided into three groups.The enrolled population was divided into three groups: Q1 group(3.5 ≤ FT3 ≤ 4.72 pmol/L,418 cases),Q2 group(4.73 ≤ FT3 ≤ 5.27 pmol/L,411 cases),and Q3 group(5.28 ≤ FT3 ≤ 6.5 pmol/L,408 cases).The general clinical characteristics and incidence rate of gonadal dysfunction of the three groups were compared.And divide men into two groups based on whether they experience hypogonadism: the normal group and the hypogonadism group,and compare the clinical characteristics of each group.Construct a binary logistic regression model to correct for other influencing factors that previously had significant differences between the male normal and male hypogonadism groups,and discuss whether FT3 is a contributing factor to male hypogonadism.Use SPSS to plot a time dependent ROC and obtain the optimal predictive threshold for the development of FT3 in sexual dysfunction.Perform relevant statistical analysis using SPSS 26.0.The measurement data conforming to the Normal distribution is expressed in ± s,the inter group comparison is performed by t test,and the multi group comparison is performed by one way ANOVA.Non Normal distribution is represented by M(Q25,Q75),Mann Whitney U-rank sum test is used for inter group comparison,and Kruskal Wallis H test is used for multi group comparison.The Spearman method was used for correlation analysis,and bilateral tests were used.The statistical description of counting data is represented by n(%),and the comparison between groups is conducted using a 2-test.The influencing factors of hypogonadism were analyzed using binary logistic regression analysis.The cut point and predictive value were compared using the subject’s work curve(ROC)and area under the curve(AUC),and the best FT3 cut point value of male hypogonadism was analyzed according to the maximum Youden’s J statistic as the critical value.P<0 05 represents a statistically significant difference.Results:1.Comparison of General Clinical Characteristics of Patients Grouped in FT3 Triad.There are a total of 1237 males.Male patients were divided into three groups based on the two cut-off points of the FT3 level quartile(4.72,5.27):Q1 group(3.5≤FT3≤4.72pmol/L,418cases),Q2 group(4.73≤FT3≤5.27pmol/L,411 cases),and Q3 group(5.28≤FT3≤6.5pmol/L,408 cases).The results showed that there were statistical differences between the Q1 and Q2 groups,Q2 and Q3 groups,and Q1 and Q3 groups of T(P<0.05).There were no significant differences in age,ALT,AST,Cr,TC,TG,HDL-C,LDL-C,PRL,FSH,LH,P,E2,FBG,TPOAb/Tg Ab antibody positive rates,history of coronary heart disease,hypertension,and gout among the three groups(P>0.05).2.Detection rate of male hypogonadism in FT3 groupAfter grouping according to male FT3,Pearson Chi-squared test found that the probability of hypogonadism in Q1 group was 17.2%,that in Q2 group was 3.2%,and that in Q3 group was 2.2%.There was statistical difference in the overall mean of the three groups of data(2 values=83.58,P<0.001).Compared with the Q2 and Q3 groups,the rate of male hypogonadism was significantly increased in the Q1 group,and the difference was statistically significant(P<0.05).3.Correlation analysis between FT3 levels and sex hormones.Spearman correlation analysis showed a significant positive correlation between FT3 and T value(r=0.374,P<0.01),while FT3 showed a very weak positive correlation with E2(r=0.057,P=0.045),with little statistical significance.There was no correlation between FT3 and PRL,FSH,LH,P(P>0.05).4.Comparison of general clinical characteristics of gonadal function grouping in male patients.There were a total of 1237 males in this study,including 1143 in the normal gonadal function group and 94 in the hypogonadism group(7.6%).The Mann Whitney U rank sum test was used to compare the normal and decreased gonadal function groups between the two groups.The results showed that there was a statistically significant difference(P<0.05)between the age,TC,FT3,TPOAb/Tg Ab antibody positive,coronary heart disease,and gout groups,while there was no statistically significant difference(P>0.05)between the Cr,ALT,AST,TG,HDL-C,LDL-C,TSH,FT4,FBG,and hypertension groups.5.Application of binary logistic regression analysis to analyze the influencing factors of male performance decline.Using male hypogonadism as the dependent variable and FT3 as the independent variable,a binary logistic regression analysis was conducted.The results showed that FT3 was negatively correlated with male hypogonadism and was a negative influencing factor for male hypogonadism(P<0.01).After adjusting for confounding factors such as age,TC,LDL-C,TPOAb/Tg Ab antibody positivity,coronary heart disease,gout,FT4,TSH,etc.,FT3 still showed a negative correlation with male hypogonadism,indicating that FT3 is a negative factor for male hypogonadism(P<0.05)6.The predictive value of FT3 for male sexual dysfunctionUsing FT3 as the test variable,whether male gonadal function is impaired or not as the state variable,the Receiver operating characteristic was drawn.The results showed that the AUC of male gonadal dysfunction predicted by FT3 level was 0.766(95% CI:0.741-0.841,P<0.05).According to the maximum Youden’s J statistic as the critical value,when the FT3 value is less than 4.695pmol/L,it is the best critical value to predict male gonadal dysfunction,with a sensitivity of 72.4% and a specificity of 75.5%.Conclusion: Within the normal range of the thyroid gland,there is a positive correlation between FT3 and T in males.FT3 is a negative influencing factor for male hypogonadism.The optimal critical value for predicting functional decline in FT3 is 4.695pmol/L.