An Analysis Of Correlation And It's Impacting Factors Between The Size Of Thyroid Nodules And TSH Level

Objective1.To investigate the relationship between the size of thyroid nodules and the normal range of TSH(Thyroid stimulating hormone)level.2.To explore the impacting factors of TSH.MethodA retrospective study of 332 subjects was conducted.All subjects were selected from Endocrinology Department and Physical Examination Center of The Second Affiliated Hospital of Fujian Medical University between April 2016 and December 2018.Subjects were classified into two groups using ultrasound: Group A(small nodule group,n=256)with no thyroid nodules or thyroid nodules smaller than 0.7cm in the maximum diameter,and Group B(large nodule group,n=76)with maximum nodule diameters ?0.7cm.The demographic information and measures of thyroid hormone,thyroid autoantibodies,routine biochemistry and routine blood work were collected for statistical analysis.All subjects had TSH levels in the normal reference range of 0.27-4.2 mU/L.Statistical methods were utilized to evaluate the correlation between the size of thyroid nodules and TSH.By comparing the difference of various covariates in the two groups,the potential mono-factors that may impact the size of thyroid nodules were identified.Finally,stepwise multivariate linear regression was adapted to screen for the independent factors associated with TSH.Results1.Mean TSH levels were(1.912±0.854)mU/L for group A(small nodule group)and(1.653±0.756)mU/L for group B(large nodule group).The mean difference of TSH between the two groups was statistically significant(P<0.05).There was a significant negative correlation between the nodule size and TSH(P<0.05),with the Spearman correlation r=-0.125.2.Groups A and B were significantly different in age,fatty liver,systolic blood pressure,BMI(Body mass index),FT4(Free thyroxine),urea nitrogen,fasting blood glucose,sodium,chlorine,osmotic pressure,NE%(Neutrophil percentage)and LY%(Lymphocyte percentage)(P<0.05).There were no significant differences between the groups in gender,diabetes,hypertension,diastolic blood pressure,FT3(Free triiodothyronine),TPOAb(Thyroid peroxidase antibody),TGAb(Thyroglobulin antibody),TRAb(Thyrotrophin receptor antibody),albumin,alanine aminotransferase,aspartate aminotransferase,cholesterol,triglycerides,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,creatinine,uric acid,potassium,calcium,magnesium,phosphorus,leukocytes,neutrophils,lymphocytes,red blood cells,hemoglobin and platelets(P>0.05).3.Among the mono-factors that may impact the size of thyroid nodules,FT4?NE% and LY% were the factors significantly associated with TSH levels.(P<0.01).The data also showed that only FT4 and NE% were the independent factors associated with TSH by stepwise multivariate linear regression analysis(P<0.01).Conclusions1.When TSH was in the normal reference range,subjects with larger thyroid nodules had statistically significant lower TSH level than those with smaller thyroid nodules.2.The potential mono-factors that may influence the size of thyroid nodules included age,fatty liver,systolic blood pressure,BMI,FT4,urea nitrogen,fasting blood glucose,sodium,chlorine,osmotic pressure,NE% and LY%.3.Among the mono-factors that may affect the size of thyroid nodules,FT4 and NE% were two independent factors negatively associated with TSH levels.The data suggested that FT4 and NE% may impact the nodule size by affecting the level of TSH.