title: [Investigation of thyroid function abnormalities in children in high water iodine areas of Hebei province].
abstract: OBJECTIVE
  To understand the level of thyroid function and the prevalence of the thyroid diseases of children in high water iodine areas.
  
  
  METHODS
  Two primary schools were selected by purposive sampling from Haixing county, Hebei province in April 2010. A total of 371 children were selected from six classes by cluster sampling in the schools. Morning-urine and venous blood (5 ml) were collected to measure the levels of urinary iodine, free triiodothyronine (FT(3)), free thyroxine (FT(4)) and sensitive thyroid-stimulating hormone (sTSH) in serum and to evaluate the iodine status and thyroid function of children.
  
  
  RESULTS
  The median urinary iodine of the children was 1032.08 µg/L. Overall, 96.2% (357/371) of the children's urinary iodine were ≥ 300 µg/L and 68.5% (254/371) were ≥ 800 µg/L. The level of FT(3) and FT(4) were (6.28 ± 0.81) pmol/L and (16.37 ± 2.72) pmol/L, respectively. The median of sTSH was 4.01 mU/L. The FT(4) among boys ((16.63 ± 2.60) pmol/L) was significantly higher than that among girls ((15.99 ± 2.85) pmol/L) (P < 0.05). Overall, 44 subjects were diagnosed as thyroid disease (11.9%), 25 were subclinical hypothyroidism (57% of the total patients), 4 were hypothyroidism (9%), 10 were hyperthyroidism (23%) and 5 were subclinical hyperthyroidism (11%). In the urinary iodine of 200 - 799 µg/L, the prevalence of thyroid disease and hypothyroidism were 6.3% (7/111) and 14.6% (27/254), respectively. When urinary iodine ≥ 800 µg/L, the prevalence of thyroid diseases and hypothyroidism were 3.6% (4/111) and 8.3% (21/254), respectively.
  
  
  CONCLUSIONS
  Most of the children in high water iodine areas had excessive iodine intake. Levels of the children's thyroid hormone were within the normal range. The prevalence of thyroid disease were high, in these areas and the thyroid disease were mainly the subclinical hypothyroidism.
authors.affiliation: School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.forename: Zhong-Na
authors.initials: ZN
authors.lastname: Sang
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.forename: Na
authors.initials: N
authors.lastname: Zhao
authors.forename: Long
authors.initials: L
authors.lastname: Tan
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Gui-Qin
authors.initials: GQ
authors.lastname: Zhang
authors.forename: Song-Chen
authors.initials: SC
authors.lastname: Wen
authors.forename: Wan-Qi
authors.initials: WQ
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology*; D007455:Iodine / Q000032:analysis* / Q000652:urine; D008297:Male; D015995:Prevalence; D013960:Thyroid Function Tests; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D007455:Iodine