| Purposes:We divide the target population into two groups according to the European Union recommended Tolerable Upper Limits(UL). To compare thyroid function between iodine intake is less than UL and greater than UL. To compare of lipid levels between two populations. To compare of antioxidant capacity between two populations.Methods:We implement the research by using both field investigation and second-hand material analysis. Second-hand data is from the 2008 Liu Miao graduation thesis of the graduate related database. The investigation location of second-hand material is Jiangsu Province Suining County in where chose male and female aged 18-60 as target population, altogether 200 people. The sex ratio, age distribution balanced as far as possible. Calculating the total intake of iodine, according to whether more than 600μg/d (UL standard) divided into 2 groups, the total intake of less than 600μg/d as the UL-group, the total intake of greater than 600μg /d as UL+group.The research include iodine content of water, lipid testing, including triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (apoA1), apolipoprotein B (apoB), thyroid function tests, including serum thyroid-stimulating hormone (TSH), three of the original acid iodine Thyroid (T3), free triiodothyronine three (FT3), thyroxine (T4), free thyroxine (FT4).The field investigation located in Qi County in Henan Province, choose 18-50 years old resident continuous live over 10 years, male and female in half, aitogether 200. Group method is the same as second-hand material. Except the research content of second-hand material, the field investigation increased the salt consumption survey, thyroid B-ultrasound, detection of lipid peroxidation indicators, including superoxide dismutase (SOD), glutathione peroxide physical activity (GSH-Px), malondialdehyde(MDA).Results:B-ultrasonic examination showed UL+Group goiter rate is very low, only 1.3%, UL-group have no goiter patient. Thyroid function tests found that rates of hypothyroidism and hyperthyroidism of two groups have no statistically significant difference. Serum FT4 level of UL+Group is significant lower than the UL-group level in Henan. Jiangsu scene Serum T3, T4, FT4 levels of UL+group is significant higher than the UL-group levels.Blood lipid test results showed serum TC, apoB levels of UL+Group residents are higher than the UL-group levels in Henan. To eliminate confounding factors, secondary data analysis, serum apoA1 levels of UL+ group residents is lower than UL-group. Lipid indexes abnormal rate of UL+group are higher than the UL-group, but the majority respondents' lipid levels are still in the normal range. Correlation analysis showed that in the UL+group the correlation between serum TG, apoB levels and iodine intake are positively, while serum HDL-C, apoA1 levels are negatively correlated with iodine intake. In the UL- group serum TC, TG, HDL-C, LDL-C, apoAl, apoB levels and intake of iodine content are not significantly correlation.The activities of antioxidant enzymes and oxidation product content detection results showed that the activity of serum GSH-Px and SOD of UL+group are lower than UL-group and MDA content is also lower than UL-groups. All of the results have statistically significant differences.Conclusions:The Iodine intake above the Tolerable Upper Limits do not change the thyroid morphology and the thyroid hormone levels is within the normal range. But FT4 is low, therefore increase the risk of hypothyroidism.The lipid levels of residents whose iodine intake are higher than tolerable upper limits are basically within the normal range. The abnormal blood lipid ratio has no difference whether the iodine intake level is above the UL or no. But the TC increased, apoA1 decreased, apoB increased, and all related to iodine intake. So, the risk of abnormal blood lipid is greatly increases.Although iodine intake is higher than the tolerable upper limits do not increase the residents peroxidation product content and there is no significant peroxidation damage, but the activities of antioxidant enzyme compared to whose iodine intake below the UL level is declined. The residents are in the initial period of peroxidation damage.Setting the tolerable upper limits to 600μg/d, thyroid function, blood lipid levels and antioxidant ability have been affected and produced certain change when the intake level is above that limits. So the value of SCF UL developed is relatively safe, UL is set to 1000μg/d, or 1200μg/d may cause some people thyroid dysfunction, lipid metabolism disorder and even cardiovascular disease. That will lead to greatly health hazards. |
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