| Iodine, the essential element in thyroid hormone synthetic course, plays an important role in maintaining the normal function and morphosis of thyroid. Enough thyroid hormone cannot be synthesized in the lack of iodine, which cause damaged development in brain and a series of other harmful consequences called iodine deficiency diseases (IDD), including simple goiter and cretinism. USI has been recommended by authoritative organizations to eliminate IDD all over the world, but excessive iodine has appeared with the fast progress in eliminating IDD. In order to not only prevent iodine deficiency but also avoid the dangers caused by excessive iodine, WHO has put forward the standard of the iodine nutrition state according to the school-ager's median urine iodine (MUI) as follows: 50-99ug/L as mild iodine deficiency, 100-199ug/L as adequate iodine, 200-299ug/L as more than adequate iodine, and more than 300ug/L as excessive iodineOur epidemiological Study of iodine intakes and thyroid diseases in three different rural communities of MUI 103ug/L, 374fig/L and 615ug/L, showed that the prevalence rates of overt hypothyroidism of MUI 374ug/L and 615ug/L areas were respectively as 3.2 times and 7.3 times as that of MUI 103ug/L area. The prevalence rates of sub-clinical hypothyroidism were as 3.2 and 6.6 times as that of MUI 103ug/L area, these results suggested that the excessive iodine of MUI 300(ug/L -600ug/L was dangerous for hypothyroidism. In order to evaluate the relationship between iodine intake of MUI 300ug/L -600ug/L and hypothyroidism, multifactor analysis was performed here.In order to simulate the effects of iodine supplement of MUI 300ug/L-600ug/L on common people in iodine-deficient areas, Wistar rats were employed to as study objects. The Wistar rats is easy to prepare iodine-deficient model for it is sensitive to iodine deficiency. It is suitable to simulate the state of common people for it has no tendency of autoimmune. Because it is tolerant to high iodine, the positive results would be rather eloquent. The iodine supplement level was accordant to that in epidemiological study, so our study would have great practical significance. The measurement of MUI ensured the stabilization of iodine supplement. Iodine supplement lasted 8 months, so full effect of treatment could be discovered. Our study tried to completely observe the effects of iodine supplement of 3~6times physiological need on thyroid function and morphosis of the iodine-deficient Wistar rat.MethodsEpidemiological study1. Definition of research area and object: Depending on historical materials of epidemiology and MUI level of different area pupils before investigation, three areas of MUI 83.45ug/L, 242.85ug/L, and 650.87 ug/L were selected as mild iodine deficiency, more than adequate iodine and excessive iodine areas. Taking whole group sampling method, all residents who had more than 14- year age and 5 residential years in the selected area were investigated. People who are mobilized and agreed to provide fasting vein blood and urine were included as the research objects, 1103 people (male284, female819) in mild iodine deficiency area, 1584 people (375male, 1209female) in more than adequate iodine area, andl075 people (275male,female 799) in excessive iodine area.2. Data collection: Carryied on on-the-spot questionnaire investigation to the above research objects, the content included name, sex, age, job and history of thyroid disease, etc. Gathered fasting urine and blood sample in early morning for measurement of TSH, FT3 FT4 TPOAb TgAb and urine iodine.3. Diagnostic standard: Overt hypothyroidism can be diagnosed by TSH>4.8mU/L and FT4 <10.3pmol/L; Sub-clinical hypothyroidism can be diagnosed by TSH> 4.8mU/L and FT4> 10.3pmol/L.4. Statistical analysis: Data were inputted by EXCEL software, analysed by SAS software. x2test, T-test, ANOVA were applied in single factor analysis. Logistic Regression was applied for multifactor analysis. Non-normal distribution data was changed into logarithm form f...
|
PDF Full Text Request