Analysis of thyroid hormone level and its influencing factors among pubertal girls in Minhang District of Shanghai / 中国学校卫生

ABSTRACT

Objective@#To investigate thyroid hormone concentration and associated factors among pubertal girls in Minhang District of Shanghai.@*Methods@#From January to March 2019, a stratified sampling method was used to select junior high schools from the east, south, north, and middle areas in Minhang district. A total of 386 girls of grade 6 in selected schools were included in the study. Physical examination was conducted, and their urine and blood samples were collected to determine urinary iodine concentration (UIC) and thyroid function. Puberty Development Self-rating Scale (PDS) was used to define the pubertal stage. Logistic regression models were conducted to analyze the associations between pubertal stage and thyroid function.@*Results@#The median urinary iodine concentration was 163.57(106.57, 232.96) μg/L. The geometric mean values of TSH, TT3, FT3 and FT4 were 0.29 mU/L, 0.26 nmol/L, 0.68 pmol/L and 1.18 pmol/L.The mean value of TT4 was 91.64 nmol / L. The abnormal rates of TGAb and TPOAb were 6.22% and 4.15%. The rate of abnormal TGAb combined with abnormal TPOAb was 3.68%. Girls in puberty and post-puberty had the lower level of TT4 (OR=0.47,0.43) as compared with girls in pre-puberty stage. Obese girls had higher level of TT3(OR=9.08, 95%CI=1.52-54.07). With the increase of exercise time(0.5-1, >1 h/d), FT4 level was increased (OR=2.45, 2.19). TSH levels were significantly higher in girls with higher TGAb and TPOAb. Girls had higher TT4 or FT4 levels if their TGAb levels were higher and TPOAb levels were normal.@*Conclusion@#There is an association between pubertal stage, obesity, exercise and thyroid function in school-aged girls during puberty in iodine sufficient areas. TSH, FT4 and TT4 levels are correlated with TGAb and TPOAb levels.