Abstract:

Objective To investigate the detectable rates of subclinical hypothyroidism (SH) of children aged 8-10 years,adults aged 18-45 years,breastfeeding women and pregnant women,and analyze the differences of the detectable rates in different people with different levelsof urinary iodine concentrations and immune status in order to provide new indexes for prevention and treatment of iodine deficiency disorders.Methods  A cross-sectional survey was performed in four kinds of 1 999 target people (633 children aged 8-10 years,703 adults aged 18-45 years,334 breastfeeding women and 329 pregnant women) in six different areas in China from the April 2009 to April 2010.The morning blood samples and three urine samples selected randomly of different people were collected and the thyroid stimulating hormone(TSH),free thyroxine(FT4),thyroid microsome antibody(TMAb),thyroid globulin antibody(TGAb) in blood samples and iodine in urine samples were detected.ResultsThe detectable rates of subclinical hypothyroidism of children aged 8-10 years old,adults aged 18-45 years old,breast feeding  women and pregnant women were 10.43%,4.84%,4.19%, and 3.95%,respectively.The detectable rate of SH in children group was significantly higher than that in adults group (P<0.01).There was no significant differences of the detectable rates of SH between children whose urinary iodine were normal and children whose urinary iodine were elevated (P>0.05).The positive rates of  TMAb and TGAb of people with SH were significantly higher than those of people with normal thyroid function(P<0.01).Conclusion The detectable rate of SH  of children aged 8-10 years is higher than those in   other three groups,which indicates that  the index of SH should be used in   routine monitoring of iodine disorder control in  children. 

Key words: subclinical hypothyroidism;urinary iodine;thyroid autoantibodies