title: [An epidemiological study on the relationship between selenium and thyroid function in areas with different iodine intake].
abstract: OBJECTIVE
  To investigate the relationship between selenium status and thyroid dysfunction in 3 areas with different iodine intake.
  
  
  METHODS
  An epidemiological research was performed in the rural communities of Panshan County (iodine-deficient area) and Zhangwu County (iodine-sufficient area), Liaoning Province, and Huanghua County, Hebei Province (iodine-excessive area). Serum selenium, TSH, FT3 and FT4 levels were examined in 329 patients with thyroid dysfunction (including clinical hypothyroidism, subclinical hypothyroidism, clinical hyperthyroidism and subclinical hyperthyroidism) and 183 normal inhabitants.
  
  
  RESULTS
  The median serum selenium concentrations in Panshan, Zhangwu and Huanghua were 91.4, 89.1, and 83.2 microg/L respectively. There was no difference in serum selenium levels between the patients with subclinical hypothyroidism, clinical hypothyroidism, and clinical hyperthyroidism and their normal controls. The median serum selenium concentration of the subclinical hyperthyroidism patients was 82.6 microg/L, significantly lower than that of the normal controls (87.3 microg/L). The FT3/FT4 ratio was decreased, the FT4 level was increased in the subclinical hyperthyroidism patients in comparison with the normal controls, and no significant difference in FT3 level was found between them. No significant effect of sex and age was found on serum selenium level of normal inhabitants. In normal controls serum selenium was inversely correlated with serum TSH level, and the subjects with serum selenium < or = 80 microg/L had the median TSH level of 2.10 mU/L, markedly higher than that of the subjects with the serum selenium of 80-100 microg/L (1.29 mU/L) and that of the subjects with the serum selenium of 100 approximately 120 micro g/L (1.28 mU/L). For the thyroid dysfunction patients with positive thyroid auto-antibody (TPOAb) in Zhangwu County, the serum selenium was negatively associated with TPOAb level. The serum selenium level of the TPOAb highly positive group (TPOAb > 600 IU/ml) was 83.6 IU/ml, significantly lower than those of the TPOAb lowly positive group and TPOAb moderately positive group (83.6, 92.9 and 95.6 microg/L respectively).
  
  
  CONCLUSIONS
  No obvious effect of selenium status is found on the development of thyroid dysfunction in these three areas. But selenium deficiency can impair thyroid function by means of disturbing thyroid hormone metabolism and decreasing antioxidant ability of the thyroid.
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Ya-jie
authors.initials: YJ
authors.lastname: Tong
authors.forename: Wei-ping
authors.initials: WP
authors.lastname: Teng
authors.forename: Ying
authors.initials: Y
authors.lastname: Jin
authors.forename: Yu-shu
authors.initials: YS
authors.lastname: Li
authors.forename: Hai-xia
authors.initials: HX
authors.lastname: Guan
authors.forename: Wei-bo
authors.initials: WB
authors.lastname: Wang
authors.forename: Tian-shu
authors.initials: TS
authors.lastname: Gao
authors.forename: Xiao-chun
authors.initials: XC
authors.lastname: Teng
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Xiao-guang
authors.initials: XG
authors.lastname: Shi
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Na
authors.initials: N
authors.lastname: Man
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Xiu-juan
authors.initials: XJ
authors.lastname: Guo
mesh_terms: D000367:Age Factors; D001323:Autoantibodies / Q000097:blood; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D012643:Selenium / Q000097:blood*; D012737:Sex Factors; D013961:Thyroid Gland / Q000276:immunology / Q000502:physiology*; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D001323:Autoantibodies; D013963:Thyroid Hormones; D007455:Iodine; D012643:Selenium