| ObjectivesThe research aims to investigate the environmental(water and soil) iodine level, iodine salt three rates(rate of iodized salt, qualified iodized salt and consuming rate of qualified iodized salt), concentration of salt iodine and salt intake of target population, iodine status among childbearing age women(new married, pregnant and lactating women) of six ecological regions in Gansu Province. Meanwhile, the relationship between the environmental iodine level, concentration of salt iodine, salt intake and the iodine status among childbearing age women were analyzed in order to provide the basis for adjusting measures and supplement iodine scientifically to different ecological regions conditions.MethodsConsulting correlative papers and according to different topography and climate conditions, Gansu province was divided into six ecological regions. Stratified cluster sampling method was adopted to this research. Five counties were chosen from each ecological region and a town was chosen from each county according to orientations of east, west, south, north and center. The monitoring indexes included: 1.The environmental iodine level.(1) Water iodine monitoring. Two water samples were collected from source water of water supply project in central water supply areas. Ten towns of each county that covered the most population were chosen according to the water type and scope. If the town number was not enough, then all towns were selected. According to the orientations of east, west, south, north and center, one water sample was collected from these towns to detect iodine content by the method of suitable for iodine deficiency area and high iodine area which was recommended by the national IDD reference laboratory.(2) Soil iodine monitoring. One soil sample was chosen from each town to detect iodine content by amplified reaction colorimetric method. 2. Iodine salt and salt intake survey. Sixty salt samples were chosen to detect the iodine concentration from salt of each town by direct titration, genral method in salt industry(GB/T 13025.7-2012), sichuan salt and other special salts by arbitration laws. At the same time, twenty families of three towns from five towns were chosen to investigate salt intake. 3. Iodine nutrition status survey among childbearing age women. Ten women of each group(new married, pregnant, lactating women) of childbearing age were chosen to detect urinary iodine concentrations(UIC) by arsenic cerium catalytic spectrophotometry.Results1. Environmental iodine level.(1) The median of total water iodine was 3.25 ?g/L, and the iodine content in groundwater was significantly higher than that in surfacewater(Z=-8.493, P<0.05). The water iodine medians of Desert Region and Loess Plateau-gully Region were 10-150 ?g/L which fit for the suitable range. The other ecological regions were all below 5 ?g/L. There was a significant difference of water iodine among six regions(H=708.006, P<0.05).(2) The median of total soil iodine was 12.70 ?g/L. There was a significant difference of soil iodine among six regions(H=62.775, P<0.05).(3) There was a negative correlation between water iodine and soil iodine generally among six regions(r=-0.206, P<0.05). Whereas, there was no significant differences of water iodine and soil iodine among other regions except for Desert Region(r=0.632, P<0.05).2. Iodized salt and salt intake.The coverage rates of iodized salt were all above 99%, rates of qualified iodized salt were all above 95%, and the consuming rates of qualified iodized salt were all above 93% among six ecological regions. The total median of salt iodine was 26.20 mg/kg, ranging from 24.36 to 28.30 mg/kg and there was a significant difference(H=529.131, P<0.05). The mean of daily salt intake was 9.04 g, ranging from 4.50 to 12.62 g. There was a significant difference among six regions(F=47.562, P<0.05).3. The iodine status of childbearing age women.(1) The iodine status of new married childbearing women. The total UIC median of the new married childbearing women was 172.74 ?g/L. They were all in the range from 100 to 200 ?g/L except for Gobi Region of Hexi Corridor and Loess Plateau-gully region(above 200 ?g/L) and there was a significant difference(H =84.596, P<0.05). Among them, the UIC medians of Gobi Region of Hexi Corridor and Loess Plateau-gully region were significantly higher than those of others(all P<0.05).(2) The iodine status of pregnant women. The total urine median of pregnant women among six regions was 144.19(ranging from 131.03 to 178.80) ?g/L. Among them, only Loess Plateau-gully region reached 178.80 ?g/L and the others were all below 150 ?g/L. There was a significant difference(H=18.556, P<0.05). The urine iodine medians of all pregnant women at the early, middle and late pregnancy were less than 150 ?g/L, respectively 133.82 ?g/L, 136.51 ?g/L, and 149.78 ?g/L and there was no significant difference(H=3.282, P>0.05). Whereas, there was a significant difference of the urine iodine at early pregnancy among different regions(H=22.223, P<0.05). And, there is a significant difference of the urine iodine level in different pregnancy between Loess Plateau-gully region and Zhongshan Valley of Qingling Mountains(H=10.272, 6.076, all P<0.05).(3) The iodine status of lactating women. The total UIC median of the lactating women was 149.05(ranging from 128.79 to 194.10) ?g/L. There was a significant difference of the lactating women UIC among different regions(H=72.867, P<0.05). The UIC(less than 50 ?g/L) proportion of lactating women in Grassland Meadow Area of Gannan Plateau was more than 20%(namely 21.28%).Conclusions1. Only Desert Region and Loess Plateau-gully Region are sufficient iodine area among six ecological regions and the others are all environmental iodine deficient areas. 2. The iodized salt concentrations of six regions are all in the recommended range of Gansu province. There is a considerable difference of the salt intake among different regions.3. The iodine status of childbearing age women in six regions.(1) The iodine nutrition of new married women of childbearing age is all in suitable condition except for Loess Plateau-gully region which is in the high requirements level.(2) There is a universal problem of insufficient iodine nutrition on pregnant women except for Loess Plateau-gully region and the most serious region is Grassland Meadow Area of Gannan Plateau.(3) The iodine nutrition of lactating women is adequate generally. However, there were some potential risks of iodine nutrition deficiency in Grassland Meadow Area of Gannan Plateau.4. The environmental iodine level has an effect on iodine nutrition and the concentration of salt iodine and salt intake are the main factors which influence UIC of childbearing age women among different regions. On the premise that salt intake of people is invariant, the present salt iodine concentration of Gansu province will not be able to well meet the demand of iodine nutrition of pregnant women, whereas, it can satisfy the new married women of childbearing and lactating women. |
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