Analysis Of The Correlation Among Gestational Hypothyroxinemia With Iodine Nutrition State And Clinical Indexes

ObjectiveTo investigate the correlation among gestational hypothyroxinemia,iodine nutrition state and clinical indexes.MethodsBy using retrospective analysis,509 puerperas treated in the Second Affiliated Hospital of Fujian Medical University from January 2017 to November 2019 were selected as the research objects.The age,gestational week,parity,gravidity,past medical history,height,weight,body mass index(BMI),systolic pressure,diastolic pressure,urinary iodine,free triiodothyronine(FT3),free thyroxine(FT4),thyroid stimulating hormone(TSH),thyroid peroxidase antibody(TPOAb),thyroglobulin antibody(TGAb),thyrotropin receptor antibody(TRAb),albumin,(ALB),Alanine amintransferase(ALT),Asparate aminotransferase,(AST),total bilirubin(TBIL),Alkaline phosphatase(ALP),γ-glutamyl transferase(GGT),Uric acid(UA),Blood urea nitrogen(BUN),Creatinine,CREA),White blood cell(WBC),Hemoglobin(HGB),Platelets(PLT).According to the reference value of thyroid function,the puerperas were divided into two groups: low thyroxine group(group A): FT4<12pmol/L(laboratory dept)or FT4<11.48pmol/L(nuclear medicine dept),with 259 cases;normal thyroxine group(group B),FT4≥12pmol/L or FT4≥11.48pmol/L,with 250 cases.The normality of all the measurement data was tested by K-S test.The continuous numerical variables were denoted by the mean±standard deviation(x ±s),Skew distribution data is represented by median with quartile range(IQR),and the means of two samples were compared by Mann-Whitney U test(P<0.05 represented that the difference was statistically significant);the classified variables were described by case number(rate),and the comparison between groups was made by Chi-square test(P<0.05 represented that the difference was statistically significant).Pearson correlation analysis was used to analyze the correlation between measurement data and FT4,and Spearman rank correlation was used to analyze the correlation between categorical data and FT4.Stepwise linear regression analysis was adopted as the method of multiple-factor analysis.Results1、The differences in body weight,BMI,TPOAb,TRAb,blood platelet,total bilirubin,GGT and CREA between the low thyroxine group(group A)and the normal thyroxine group(group B)(P<0.05)were statistically significant,while the differences in age,gestational weeks,height,TSH,TGAb,leukocyte,hemoglobin,AST,ALT,ALB,alkaline phosphatase,systolic pressure,diastolic pressure,gravidity,parity,gestational diabetes mellitus and hypertension were not statistically significant(P>0.05).2、The median of urinary iodine in the low thyroxine group and the normal thyroxine group was respectively 148.4μg/L and 163.85μg/L,which respectively belonged to the level of iodine deficiency and moderate iodine.According to the level of urinary iodine,the 509 objects were divided into iodine deficiency group,moderate iodine group and excess iodine group.In group A and group B,the proportion of objects with iodine deficiency was 50.96% and 46.8%,respectively,the proportion with moderate iodine was respectively 34.75% and 38.8%,the proportion with excess iodine were 14.29% and 14.4%,respectively,and the differences were not statistically significant.Spearman correlation analysis and regression analysis were conducted on the FT4 level and urinary iodine level(iodine deficiency group=1,moderate iodine group=2,excess iodine group=3).The results suggested no significant correlation between hypothyroxinemia and iodine nutrition state.3、The common clinical indexes that affect hypothyroxinemia include BMI,GGT,thyroid autoantibodys,CERA and TBIL;the level of FT4 is negatively correlated with BMI and GGT,and positively correlated with CERA and thyroid autoantibodys.The results of multiple regression analysis showed that TPOAb,GGT and CERA are independently correlated with FT4.Conclusion The urinary iodine of puerperas with gestational hypothyroxinemia was in the level of mild iodine deficiency,but no significant correlation was found between hypothyroxinemia and urinary iodine level.Among the clinical reference indexes that may affect hypothyroxinemia,the level of FT4 is negatively correlated with BMI and GGT,and positively correlated with CERA and thyroid autoantibodys.The results of multiple regression analysis showed that TPOAb,GGT and CERA are the influencing factors of gestational hypothyroxinemia.