Objective To explore the iodine status of pregnant women after 17 years of salt iodization in rural areas of Shijiazhuang City.Methods Probability proportionate to size sampling was employed in which 30 towns were selected from the 211 towns in the rural areas of Shijiazhuang City.In each town selected,40 pregnant women were randomly selected to collect their spot urine samples,edible salt samples and drinking water samples from their households to measure iodine content.The iodine content of salt was determined quantitatively using a titration method (GB/F 13025.7-2012).The urinary iodine content was determined using the method of ammonium persulfate digestion arsenic cerium catalytic spectrophotometry (WS/T 107-2006).The iodine content in drinking water was determined by the method of standard test for drinking water.Results A total of 1 200 salt samples was collected from the pregnant women's households in 30 towns,with the overall median iodine content being 27.2 mg/kg.The median salt iodine content in 30 towns varied from 23.4 to 32.6 mg/kg.A total of 478 water samples were collected,with a median of 5.3 μg/L.The median urinary iodine content (UIC) of 1 200 pregnant women in 30 towns was 146.4 μg/L.The median UIC in the first (≤ 13 weeks),second (14 ～ 26 weeks) and third (≥27 weeks) trimesters was 166.3,145.1 and 133.5 μg/L,respectively.The median UIC in the first trimester was significantly higher than that in the third trimester (Mann-Whitney Test,U =18 265,P ＜ 0.05).Except for the 9-20 and 37-40 weeks period of pregnancy,the median UIC was lower than the WHO criteria (150 μg/L).Tested by linear correlation,the pregnant women's median UIC did not correlate with median salt iodine (r =0.725,P ＞ 0.05).Conclusion Under the current universal salt iodization,the pregnant women's iodine intake could almost meet their requirement in the rural areas of Shijiazhuang City,however,mild iodine deficiency has existed in the third trimester.Alternative measures of iodine supplement could be implemented.

Objective To access the effectiveness of withdrawing iodized salt on correcting the iodine excess in the population living in high iodine areas.Methods Before withdrawing iodized salt,2 twons were selected from each of 5 cities with water-borne iodine excess areas in Hebei province.All the selected towns were divided into 7 groups according to their iodine content in drinking water.Two villages wereselected from each group where urine samples of children aged 8 to 10 years old were collected to investigate the change of urinary iodine content of these children before and after withdrawing iodized salt.The urinary iodine content was determined using the method for determination of ammonium persulfate digestion arsenic cerium catalytic spectrophotometry (WS/T 107-2006).Correlation between children's urinary iodine and drinking water iodine was analyzed.Results Before and after withdrawing iodized salt,744 and 771 urine samples were collected from the examined children aged 8-10 years respectively.The overall median urinary iodine content (MUIC) of the examined children after withdrawing iodized salt (350.1 μg/L) decreased significantly than that of before withdrawing iodized salt (460.8 μg/L,U =3 127.8,P ＜ 0.05).After withdrawing iodized salt,the MUIC of the children decreased significantly in 8 of 12 villages (P ＜ 0.05).Before and after withdrawing iodized salt,the percentage of urine samples with iodine content above 300 μg/L was 76.7％ (571/744),58.5％ (451/771) respectively,with significant statistical difference (x2 =57.7,P ＜ 0.05).After withdrawing iodized salt,Children's MUIC also decreased significantly across gender and age (boys:558.5,351.6 μg/L,U =960,P ＜ 0.05; girls:522.9,355.5 μg/L,U =698,P ＜ 0.05; 8 years old:536.0,295.5 μg/L,U =529.5,P ＜ 0.01; 9 years old:386.2,323.2 μg/L,U =753.5,P ＜ 0.01; 10 years old:525.5,368.8 μg/L,U =521.5,P ＜ 0.05).The children's MUIC correlated positively with the median water iodine contert (MWIC) in the villages where they lived (r =0.951,P ＜ 0.01).Analyzed by linear regression,approximately 89％ of the variability in MUIC was associated with variability in MWIC.Conclusions Withdrawing iodized salt could only correct the iodine excess caused by consuming iodized salt in the population living in the areas with MWIC below 100 μg/L.In the areas with water iodine above 100 μg/L,intervention should be focused on seeking water with proper iodine content.

OBJECTIVEUsing the thyroid volume criteria for body surface area (BSA) to assess more precisely the effectiveness of removing iodized salt on the goiter status of children living in areas with excessive iodine in drinking water.

METHODSThree towns with median water iodine (MWI) of 150-300 µg/L were selected by simple random method in Hengshui city of Hebei province of China in May of 2010. A total of 452 and 459 children in the 3 towns were randomly selected to measure thyroid volume by ultrasound. Iodized salt was removed in July of 2010. In October of 2013, 459 children in these 3 towns were selected by simple random method to measure their thyroid volume by ultrasound again. Their goiter status was judged using the criteria of thyroid volume for BSA recommended by the WHO.

RESULTSAfter removing iodized salt, the overall BSA specific goiter prevalence in the three towns significantly decreased from 33% (149/452) to 6% (30/459) (χ² = 100.64, P < 0.001). The BSA specific goiter prevalence in 8, 9 and 10 year-old children decreased respectively from 38% (35/92), 31% (59/193) and 33% (55/167) to 6% (10/164), 7% (11/163) and 7% (9/132) (χ² values were 41.35, 31.66, 29.79, P < 0.001). The BSA specific goiter prevalence in boys and girls decreased from 34% (83/244) and 32% (66/208) to 6% (14/225) and 7% (16/234) (χ² values were 55.01, 45.06, P < 0.001) respectively.

CONCLUSIONThe BSA specific children's goiter prevalence decreased significantly after removing iodized salt from their diet in the HIA in Hebei province.

Body Surface Area ; Child ; China ; Diet ; Drinking Water ; Female ; Goiter ; Humans ; Iodine ; Male ; Prevalence ; Sodium Chloride, Dietary ; Water

Objective To understand the prevalence of goiter and nodule as well as the iodine nutritional status of 8 to 10 years old children after changing water source with lower iodine so as to evaluate its intervention effectiveness.Methods From 2014 to 2017,Machang Village and Liangzhang Village of Haixing County in Haixing County were selected as monitoring sites in the water-sourced high iodine area in Hebei Province.Using the cross-sectional survey method,100 children aged 8 to 10 years old were randomly selected in each village,half male and half female.Dynamic monitoring of drinking water iodine content,children's prevalence of goiter and nodule as well as urinary iodine content were conducted before and 1-3 years after changing water resource.Iodine detection was performed using an arsenic cerium-catalyzed spectrophotometric method suitable for iodine-deficient and high-iodine areas (recommended method for national iodine deficiency disease reference experiment);urinary iodine was detected by arsenic cerium catalytic spectrophotometry (WS/T 107-2006).The thyroid test was performed using the B-ultrasound method and the criterion was based on the "Diagnostic Criteria for Endemic Goiter" (WS 276-2007).Results The median iodine content of water in the two villages before the reformation was 861.0 μg/L,and it was 71.6,29.1 and 30.4 μg/L in 1-3 years after water was changed.The overall difference before and after water change was statistically significant (x2 =8.48,P ＜ 0.05).The median urine iodine of children in the two villages before the change of water was 705.0 μg/L,and the median urine iodine of children was 306.0,143.0 and 140.0 μg/L after 1-3 years.The differences were statistically significant (Z =6.56,10.82,11.19,P ＜ 0.05).The goiter rate was 10.3％ (21/203) before changing water,and the goiter rate was 6.3％ (13/205),6.4％ (13/203) and 3.8％ (8/208) in 1-3 years after water exchange,and the difference between before and 3 years after water exchange was statistically significant (x2 =6.61,P ＜ 0.05).Children's nodule prevalence before and 3 years after changing water was 11.3％ (23/203) and 1.4％ (3/208),the difference was statistically significant (x2 =13.42,P ＜ 0.05).Conclusion Three years after changing water resource,children's goiter prevalence is back to normal in general,and nodule prevalence is decreased significantly,which indicates sound intervention effectiveness.