ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the effectiveness of universal salt iodization (USI) for the control of IDD in Hebei province since it was implemented in 1995, identify the problems currently encountered in the implementation of USI and provide practical proposals for addressing these problems.</p><p><b>METHODS</b>Probability proportionate to size sampling (PPS) was employed in the surveillance of IDD, for which a total of 1200 school children aged 8-10 years were randomly selected from 30 counties around the whole province during each IDD survey. The iodine content of salt was determined quantitatively with the titration method. The iodine content of urinary samples was measured by the method of ammonium persulfate oxidation.</p><p><b>RESULTS</b>The coverage of iodized salt increased from 65.0% in 1995 to 98.0% in 1999, then decreased to 88.1% in 2005 which was below the national standard of 90%. The median urinary iodine of children aged 8-10 years varied between 160.1 microg/L and 307.4 microg/L, which was above the national standard. The proportion of urinary samples with iodine content above 300 microg/L was over 30% in 2005, implying exorbitant iodine nutrition among the children. The goiter rate (TGR) among children aged 8-10 years dropped from 11.8% in 1995 to 2.7% in 2005, indicating that the spread of endemic goiter was under control.</p><p><b>CONCLUSION</b>Preliminary elimination of IDD was achieved by USI in Hebei province. Nevertheless, some problems still existed in USI such as non-iodized salt competition, over iodization and un-standardized iodization. In order to address these problems, the management and supervision of salt market needs to be strengthened to prevent non-iodized salt from reaching households; updating equipment and modifying techniques are also necessary to ensure the quality of iodized salt; to clarify the causes of excessive urinary iodine content, the various sources of iodine from the diet need to be investigated in the future.</p>
Subject(s)
Child , Female , Humans , Male , China , Epidemiology , Goiter , Epidemiology , Hypothyroidism , Epidemiology , Iodine , Pharmacology , Urine , Nutrition Policy , Nutritional Status , Sodium Chloride, Dietary , Pharmacology , Time FactorsABSTRACT
Objective To investigate the geographical distribution of excessive iodine in drinking water and to demarc aI|e the excessive iodine regions in Hebei Province.Methods In 173 counties of Hebei Province, town was surveyed as an elementary unit.Five villages were sampled according to the direction of east,west, south,north,center in every town.If the water sources were more than 5 in a village,water was sampled according to the direction ofeast,west, south,north, center, respectively;If the water sources were less than 5 in a village, all were sampled:If the village used water of cental supply,only one sample wag collected.Arsenic-cerium catalysis was used to determine the iodine concentration of drinking water.Results Two thousands and forty-nine towns were investigated and 19 352 water samples were determined in Hebei Province.One hundred and seventy- two towns were confirmed to be excessive iodine areas,where the range of water iodine Wag 0.1～2840.4μg/L The water 8amDle with 18 358 had a water iodine median less than 150.0μg/L The areas with water iodine median less than 150.0μg/L,in between 150.0μg/L and less than 300.0μg/L,and equal to or more than 300.0 μg/L accounted for 94.86%,2.92%and 2.22%,respectively.There were 110 towns with water iodine median being between 150.0μg/L and iess than 300.0 μg/L and 62 towns with water iodine median equal to or more than 300 gμ/L.Exeessive iodine towns distributed in 33 counties of 6 cities involving 5 854 960 residents in'Hebei Provmce. MOBt of the water sources with excessive iodine Cangzhou were deep wells and there was a positive correlation between we depth and water iodine concentration (r=0.430,P<0.01), while they were shallow wells in Handan, Xingtai.Hengshui,and no correlation was found between well depth and water iodine concentration(r=-0.060,-0.119.-0.121,P>0.05).Conclusions Six cities have excessive iodine water resotlrees in Hebei Province, mostly in Handan.xingtai,Hengshui and Cangzhou Cities,which all are low-lying land.The water with excessive iodine is hypogene,and the towns with excessive iodine water distributein patchy or spot pattern.