The Prevalence Rate Of Thyroid Nodules In Dalian City And Its Influencing Factors

Background and Aim:In recent years,the prevalence of thyroid nodules and the positive rate of serum thyroid peroxidase antibody(TPOAb)and thyroglobulin antibody(TgAb)gradually increased,but the relationship between them are unclear.Therefore,in this study,we investigated the prevalence of thyroid nodules in urban residents of Dalian,analyzed of the correlation between thyroid nodules with TPOAb and TgAb,explored the related factors affecting the prevalence of thyroid nodules.Methods:Through stratified cluster sampling according to age and gender,selecting 1375 residents aged from 20 to 79 years old in Dalian city,taking the form of a questionnaire survey to collecte the relevant information including gender,age,height,weight,body mass index(BMI)and blood pressure.Fasting blood samples were collected to check biochemical indexes such as fasting plasmas glucose(FPG),hemoglobin Alc(HbA1c),triglycerides(TG),total cholesterol(TC),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),thyroid stimulating hormone(TSH),free thyroxine(FT4),free triiodothyronine(FT3),TPOAb and TgAb.Thyroid nodules were clearly defined by B ultrasonography.The SPSS 22.0 statistical software was used to analysis data.The continuous data was analyzed using t test.Chi square test or Fisher exact test was used to compare the rate between group.Multivariate Logistic regression was used to analysis the independent risk factors of thyroid nodules,the difference was significant when P<0.05.Results:1375 subjects were included in this study,including 699 males(50.8%)and 676 females(49.2%),with an average age of 42.96±15.08 years.1.Compared with non nodular group,age(51.10±14.43years vs 39.18±13.83 years,P=0.000),waist circumference(87.58±10.66cm vs 83.79±11.25cm,P=0.000),BMI(24.79±3.48Kg/m2 vs 23.80±3.69Kg/m2,P=0.000),FPG(5.48mmol/L,5.13-6.09 mmol/L vs 5.22mmol/L,4.94-5.59mmol/L,P=0.000),HbAlc(5.50%,5.10-5.90%vs 5.20%,4.90-5.50%,P=0.000),systolic pressure(127.88±20.32mmHg vs 120.38±17.56mmHg,P=0.000),diastolic blood pressure(82.29±11.91mmHg vs 79.15±11.31mmHg,P=0.000),TC(5.15±1.05mmol/L vs 4.86±0.95mmol/L,P=0.000),TG(1.33mmol/L,0.87-1.94mmol/L vs 1.13mmol/L,0.75-1.82mmol/L,P=0.000),LDL-C(3.28±0.85mmol/L vs 3.04±0.79mmol/L,P=0.000)and TPOAb(7.72IU/mL,5.8610.88IU/mL vs 7.14IU/mL,5.61-9.78IU/mL,P=0.003)in nodule group increased significantly(P<0.01),TSH(1.95mIU/L,1.34-2.85mIU/L vs 2.20mIU/L,1.56-3.04 mIU/L,P=0.000)decreased significantly(P<0.01).2.The total prevalence rate of thyroid nodules was 31.8%,the prevalence of thyroid nodules in male was 28.3%and in female was 35.3%.The prevalence of thyroid nodules in female was significantly higher than that in male(P=0.006).After age standardization,the overall prevalence rate of thyroid nodules was 36.7%,the prevalence of thyroid nodules in male was 32.9%and in female was 40.8%.The positive rate of TPOAb was 4.1%(56/1375),the positive rate of TgAb was 4.5%(62/1375),and the positive rate of TPOAb plus TgAb was 6.2%(85/1375).The total positive rate of TPOAb was 10.3%(141/1375),the total positive rate of TgAb was 10.7%(147/1375).3.Stratifying analysis by gender showed that the prevalence of thyroid nodules had no obvious difference in the different antibody.In normal TSH group,Thyroid nodules associated with TPOAb and TgAb in subjects aged 70～79 years old(P<0.01),When both TPOAb and TgAb were positive,they all accompanied with thyroid nodules.The occurrence of thyroid nodules had no significant correlation with TPOAb and TgAb by stratified analysis of other age or sex.4.Thyroid nodules as the dependent variable,age,gender,waist circumference,BMI,FPG,HbAlc,SBP,DBP,TC,LDL-C,UI,TG,TPOAb,TgAb,TSH as the independent variables for Logistic regression showed that TPOAb and TgAb were not independent risk factors for the prevalence of thyroid nodules,while gender,age,LDL-C and TG were independent risk factors for the prevalence of thyroid nodules,and we also found that TC and TSH were protective factors for the prevalence of thyroid nodules.Conclusions:1.The overall prevalence rate of thyroid nodules was 36.7%in Dalian City,the prevalence of thyroid nodules in male was 32.9%and in female was 40.8%,the prevalence of thyroid nodules in female was significantly higher than that in male.2.The positive rate of TPOAb was 4.1%,the positive rate of TgAb was 4.5%,both TPOAb and TgAb were positive about 6.2%.The overall positive rate of TPOAb was 10.3%,the overall positive rate of TgAb was 10.7%.3.When TSH was normal and both TPOAb and TgAb were positive,subjects aged 70～79 years old all accompanied with thyroid nodules,there were no differences in the other cases.4.Gender,age,LDL-C,TG are independent risk factors for thyroid nodules.However,TPOAb and TgAb were not the independent risk factors of thyroid nodules,TC and TSH were protective factors for the prevalence of thyroid nodules.