Survey of thyroid volume of school children of Chongqing in 2011 / 中国地方病学杂志

Objective To find out the current thyroid volume of school children and its influencing factors in Chongqing.Methods Probability sampling method(PPS) was used to select 30 counties in Chongqing in 2011.Forty children aged 8-10of 1 randomly selected school from every county chosen were enrolled in the study.Thyroid volume of children was examined by B-ultrasonograghy.Body height and body weight were measured.The relationship between gender,age,height and weight and thyroid volume was analyzed,respectively.Results One thousand three hundred and twenty-two children aged 8-10 were investigated.The median of thyroid volume was 3.53 ml.The goiter rate was 5.52％ (73/1322).Thyroid volume of female and male was 3.55 and 3.51 ml,respectively.There was no significant difference of thyroid volume between female and male (H =0.68,P ＞ 0.05).Thyroid volume of children aged 8,9 and 10 was 3.30,3.53 and 3.76 ml,respectively.There was a significant difference of thyroid volume among different age groups(H =52.49,P ＜ 0.01).Thyroid volume of children height (110-,120-,130-and ≥140 cm,respectively) was 2.96,3.22,3.59 and 4.13 ml.There was a significant difference of thyroid volume among different height groups (H =149.23,P ＜ 0.01).Thyroid volume of children weight(17-,20-,30-and ≥40 kg,respectively) was 2.71,3.31,3.91 and 4.74 ml.There was a significant difference of thyroid volume among different weight groups(H =138.44,P ＜ 0.01).For the coefficients of simple and partial correlation,there was a significant correlation between thyroid volume and age,height and weight (P ＜ 0.05).The Spearman coefficient was 0.2411,0.3950 and 0.4285,respectively.The partial correlation coefficient was 0.0640,0.1154 and 0.2319,respectively.The standard partial coefficient of age,height and weight was 0.640,0.1154 and 0.3410,respectively.The proportion of the standard partial coefficients was 1 ∶ 1.8 ∶ 5.3.The function of body weight to thyroid volume was 5.3 times that of age and 3.0 times that of body height.Conclusions The goiter rate of schoolchildren in Chongqing is relatively high.Thyroid volume is affected by age,body height and body weight.The relationship between thyroid volume and iodine nutrition needs further study.

Feasibility of reducing iodine concentration in edible iodized salt in Chongqing / 中国地方病学杂志

Objective To analyze the characteristics of urinary iodine and edible iodized salt,and to provide suitable iodine concentration in iodized salt.Methods Sample testing was carried out to detect iodine concentration in marketed salt and child urine before salt iodization (1994).After salt iodization (2001-2010),sample testing was carried out to detect salt iodine level in manufacture,market(2001-2010) and resident household(1997-2010).Urine of children aged 8 to 10 were sampled by PPS method from 1997 to 2005.In 2009,urinary iodine of 20 children was determined in each of 5 schools,which were sampled from 5 counties located at North,South,East,West and center of Chongqing.Based on the urinary iodine and salt iodine levels before salt iodization,the relationship of urinary iodine and consumption of iodized salt was calculated.Suitable iodine concentration in iodized salt was put forward.x2 test and trend analyze approach(F-test) were used for statistical analysis.Results Before salt iodization,salt iodine level was not tested in 204 edible salt samples; the median of urinary iodine was 53.14 μg/L in 1374 children.After salt iodization,form 2001 to 2010,the average iodine levels in manufacture and wholesale salt were between 29.72-36.25 mg/kg and 30.65-36.13 mg/kg,respectively,both of them decreased significantly(F =35.35,140.59,all P ＜ 0.01),and show a downward trend.Batch quality passing rate of industry iodized salt was 100％ except in 2001,which was 92.86％.Batch quality passing rate of market iodized salt were between 88.68％-99.77％,specifically in 2001 (88.68％),in 2002(92.57％) and in 2003 (96.22％).There was no significant difference in other years (all P ＞ 0.05).The median of urinary iodine were between 238.80-328.00 μg/L,more than 35％ fall into ＞ 300 μg/L; while salt iodine increased 1 mg/kg,urinary iodine increased 5.51 μg/L-7.40 μg/L; The medium of urinary iodine of children were between 140.05-383.00 μg/L in 40 counties or districts in 2009.Reducing the iodine concentration in edible iodized salt to 20 mg/kg,the median of urinary iodine can be kept at 163.34 μg/L to 201.14 μg/L.Conclusions Iodine in iodized salt is above sufficient in Chongqing.Salt iodine should be reduced to 20 mg/kg,which will meet various population's need.

Spatial characteristics of non-iodized salt at household level based on geographic information system in Chongqing / 中国地方病学杂志

Objective To analyze the spatial distribution characteristics of non-iodized salt at household level based on geographic information system (GIS) in Chongqing.Methods The database of non-iodized salt at county level from 2001 to 2010 was established in Chongqing.By using GIS technology,the spatial distribution and spatial autocorrelation were analyzed by ArcGIS 9.3 software.Results The rate of non-iodized salt was fluctuated between 2.35％-5.78％ during 2001-2006 and the rate was reduced to less than 2.00％ after 2007.The result of spatial autocorrelation analysis on non-iodized salt from 2001 to 2006 indicated that Moran's Ⅰindex was 0.145578,0.078801,0.108033,0.091957,0.127749,0.214302,respectively(Z value was 3.066275,1.977321,2.541619,2.309972,2.900446,3.874203,respectively,all P ＜ 0.05).The spatial distribution of non-iodized salt had marked spatial cluster through Chongqing region from 2001 to 2006.The result of local spatial autocorrelation analysis from 2001 to 2006 indicated that Fengdu and Fuling were two high-risk areas(all P ＜ 0.05).Dianjiang,Yubei,Jiangbei,Wulong and Banan were also confirmed as high-risk areas in 2001,2005 and 2006(all P ＜ 0.05).The results also indicated that the distribution of non-iodized salt in the seven high-risk areas was positively correlated.The result of spatial autocorrelation analysis on non-iodized salt from 2007 to 2010 indicated that Moran's Ⅰ index was 0.018361,0.016186,0.040769,-0.059691,respectively (Z value was 1.093310,0.787361,1.071811,-0.583820,respectively,all P ＞ 0.05).The spatial distribution of non-iodized salt was at random on the whole from 2007 to 2010.However,there were four local high-risk areas.The distribution in Fengdu and Dianjiang was positively correlated,while that in Jiangjin and Shizhu was negatively correlated.Conclusions The distribution of non-iodized salt at households level in Chongqing is changed from spatial distribution before 2006 to random distribution after 2007,but there are high value areas,which should be taken as the focus of monitoring.

Analysis on the frequency of urinary iodine in a population-based intervention study / 中华流行病学杂志

Objective Through a two-year follow up program,this study was to analyze the urinary iodine frequency of a cohort in the intervention trial,concerning different doses of salt iodization,so as to explore the selection of appropriate concentration of salt iodization.Methods A multistage cluster sampling method was used to select three townships in two countries for community intervention with different doses [ ( 15 ± 5 ) mg/kg,(25 ± 5 ) mg/kg,( 35 ± 5 ) mg/kg ] of salt iodization.Results After intervention,the median of urinary iodine was reduced among the population.The urinary iodine frequencies of (15 ± 5) mg/kg and (25 ± 5) mg/kg among groups of children were mainly concentrated in 100-200 μg/L and 200-300 μg/L paragraphs in A county.While the 300 μg/Lparagraph had an overall decline in B county,the 100 μtg/L and 200 μg/L paragraph ratio increased but the trend seemed to be slow.The 100-300 μg/L paragraph of the four treatment groups took a larger proportion and kept smooth in a more ideal state.However,the control group still maintained at above 250 μg/L level.Conclusion The iodine supplementation should be gradually implemented in Chongqing.The doses of salt iodization should be reduced from the current (35 ± 15)mg/kg to (25 ± 5) mg/kg in the economically developed areas.At the same time,we need to continuously follow the changes of the condition.

Analysis of nutritional status of iodine among residents in Chongqing in 2009 / 中国地方病学杂志

Objective To investigate the nutritional status of iodine among residents in Chongqing, and to facilitate scientific prevention and control of iodine deficiency disorders. Methods Select 9 towns in each of the 40 districts (counties) in Chongqing, and collect 40 resident edible salt samples in each of the selected town to detect salt iodine by direct titrimetry. Select 5 towns on the site of the east, west, south, north and middle of every district (county), select 20 children aged 8 to 10 in each of the selected town to collect urine samples and detect urinary iodine by As-Ce catalytic spectrophotometric assay. Results The median of iodine of 14 217 salt specimens by household was 292 mg/kg with a coverage rate of qualified iodized salt of 98.90%( 14 061/14 217). The consumption rate of qualified iodized salt was 95.59%( 13 590/14 217). The median of urinary iodine for 4050 children aged 8 to 10 was 247.20μg/L, of which < 50 μg/L accounted for 4.60%(186/4050), 50-99μg/L accounted for 7.28% (295/4050), 100 - 199 μg/L accounted for 26.44% (1071/4050), 200 - 299 μg/L accounted for 25.58% (1036/4050), 300 μg/L or more, accounted for 36.10% (1462/4050). However, no significant difference was observed between different age groups(x2 = 3.77, P > 0.05). At district (county) level, the median of urinary iodine in 10(25.00%) districts (counties) was 100 - 200 μg/L, that in other 23(57.50%) districts (counties) was 200 - 300 μg/L, and that in other 7(17.50%) districts/counties was greater than 300 μg/L, and statistical significance was observed between different districts/counties (x2 = 441.95, P < 0.01). Conclusions Current iodine nutrition among residents in Chongqing is adequate. While there is excess, need to reduce the amount of salt iodization.

Construction and expression of the recombinant plasmid pET28α-Sj26GST-Sj32 of Schistosoma japonicum in Escherichia coli BL21(DE3) / 中国地方病学杂志

Objective To construct and express the recombinant plasmid pET28α-Sj26GST-Sj32 of Schistosoma japonicum(Sj) in Escherichia coli BL21 (DE3). Methods Total RNA was extracted from Sj adult worms by ultrasound-breaking, Sj26GST and Sj32 antigen gene was respectively amplified by RT-PCR from the total RNA; Sj26GST-Sj32 fusion gene obtained with gene splicing by overlap extension(SOEing) was cloned into prokaryotic expression plasmid pET28α and transformed into Escherichia coli BL2 (DE3) to construct pET28α-Sj26GST-Sj32;BL21 (pET28α-Sj26GST-Sj32) was induced with isopropyl-β-D-thiogalactopyranosid (IPTG), and the expressed products were analyzed and identified by sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE)and Western blotting. Results The 1991 bp Sj26GST-Sj32 fusion gene was successfully amplified by gene SOEing and cloned into pET28α by restriction analysis and PCR identification, the recombinant plasmid pET28α-Sj26GST-Sj32 was successfully constructed; the relative molecular mass of the expressed recombinant protein was approximately 69 × 103 by SDS-PAGE, and the amount of the expressed protein was 25% of the total bacterial proteins; the fusion protein could be recognized by sera from rabbits infected with Sj by Western blotting.Conclusions The recombinant plasmid pET28α-Sj26GST-Sj32 is successfully constructed and highly expressed in Escherichia coli in fused form with His-tag, and the expressed fusion protein shows specific antigenicity.

Comparative analysis of the survey results of iodine deficiency disorders between high-risk areas in Chongqing and in Linzhi of Tibet in 2007 / 中国地方病学杂志

Objective To investigate iodine deficiency disorders(IDD) in Chongqing and Linzhi, and to provide scientific basis for IDD control and prevention. Methods According to the national program developed in 2007, investigation was conducted in Chengkou and Wuxi county in Chongqing municipality, and Linzhi, Bomi,Milin and Langxian county in Linzhi prefecture. Five towns were sampled in Linzhi county, and 3 in other counties.In each town, one township primary school and two village primary schools were selected to inspect thyroid by B ultrasound and palpation, and urinary iodine of children aged 8 to 10 years was tested in these schools. Meanwhile,2 villages were selected in each town for test of salt iodine level and urinary iodine of childbearing age women and search cretin cases. Results Three hundred and forty families in Chongqing and 915 families in Linzhi were investigated. The coverage of iodized salt in Chongqing was 98.82%(336/340), which was significantly higher than that in Linzhi[66.34%(607/905), x2 = 139.56, P ＜ 0.01]. Goiter rate of children in Chongqing was 9.27%(89/960) by palpation and 8.34% (61/731) by B ultrasound, while goiter rate of children in Linzhi was 7.80%(102/1308) by palpation and 5.53% (69/1248) by B ultrasound. The difference of goiter rate by palpation between Chongqing and Linzhi was not statistically significant (x2 = 1.37, P ＞ 0.05 ). But goiter rate of children by B ultrasound in Chongqing was higher than that in Linzhi (x2= 5.51, P ＜ 0.05). In Chongqing, the median urinary iodine was 319.15 μg/L, and 345.75 μg/L in Chengkou county and 281.39 μg/L in Wuxi county. In Linzhi prefecture, the median urinary iodine was 189.81 μg/L, and 207.81 μg/L in Linzhi county, 161.12 μg/L in Bomi county, 131.83 μg/L in Milin county and 334.60 μg/L in Langxian county. The median urinary iodine in childbearing women were 248.42 μg/L in Chongqing and 121.25 μg/L in Linzhi. The median urinary iodine in Chongqing both in children and women were higher than those in Linzhi. No new cretin case was found in these two areas. Conclusions Goiter rate in high risk areas of IDD in Chongqing and Linzhi has decreased to less than 10%.No new cretin case is found in these areas. It can be concluded that the work of control and prevention is effective.There is excess iodine in Chongqing. In Linzhi county and Langxian county, iodine is excess in children and deficient in women. Further investigation should be conducted to find out the reason. Population iodine is excess in Bomi and Milin counties. The concentration of salt iodine should be decreased in Chongqing. In Linzhi prefecture,adding iodine measures should be adjusted based on further investigation.

Analysis of iodized salt monitoring results in Chongqing Municipality from 2001 to 2009 / 中国地方病学杂志

Objective To monitor the quality changes of iodized salt and analyze its impact factor in Chongqing between 2001 and 2009. Methods Salt samples were collected according to the east, west, south,north and center locations in iodized salt production, wholesale and household sectors. Two units in iodized salt production and wholesale segment were sampled from north, south, east and west places and only 1 unit was sampled from the central place. Nine samples were collected every month in each place. If the place had less than 9 units, and then taken all the units. About resident household, 2 townships were sampled from north, south, east and west places, and 1 township was sampled from the central place, then 20 samples were collected from each township. Iodine content was detected by oxidation-reduction assay. The index of mean iodine, qualified rate from factories and wholesale, coverage rate and taking rate of qualified iodized salt in residents were calculated.Significance was analyzed by trend test, analysis of variance and X2 test. Results The qualified rate of iodized salt from the manufacturers was 92.9%(13/14) in 2001 and the rate was 100.0% each year from 2002 to 2009. The qualified rates of iodized salt from the wholesale were 88.7%(282/318) - 99.8%(431/432). The rates of 2001 and 2002 were lower than that of other years(X2 = 4.98 - 45.69, all P 90% kept increasing. The mean iodine from the manufacturers and wholesale were 29.71 - 36.25, and 31.26 - 36.13 mg/kg, respectively. The iodine level showed a descending trend(F = 35.45, 140.59, all P 0.05 ). The iodine level from manufacturers, wholesale to inhabitants showed an descending trend(F = 38.46 - 671.23, all P < 0.01 ). Conclusions The surveillance results of iodized salt shows an increasing tendency in quality of iodized salt, eoverage rate and taking rate of qualified iodized salt. Factors that affect the quality of iodized salt is that the enterprise does not add iodine to salt strictly by the standard.

Construction and expression of the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum in Escherichia coli BL21(DE3) / 中国地方病学杂志

Objective To construct and express the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum(sj)in Escherichia coli(E.coli)B121(DE3).Methods The total RNA was extracted from sj adult worms by ultrasound-breaking,Sj26GST antigen gene was amplified by RT-PCR from the total RNA,then cloned into prokaryotic expression plasmid pET32α(+) and transformed into E.coli B12(DE3)to construct pET32α-Sj26GST;BL21(pET32α-Sj26GST)WaS induced with isopropyl-β-D-thiogalactopyranosid(IPTG),and the expressed products were analyzed and identified by SDS-PAGE and Western blot.Results The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET32α(+)by restriction analysis and PCR identification,the recombinant plasmid pET32α-Sj26GST was successfully constructed;the relative molecular mass of the expressed recombinant protein was approximately 49×103 by SDS-PAGE,and the amount of the expressed protein was 24%of the total bacterial proteins;the fusion protein could be recognized by sera from rabbits infected with sj by Western blot.Conclusions The recombinant plasmid pET32α-Sj26GST is successfully constructed and highly expressed in E.coli in fused form with Trx-tag and His-tag,and the expressed fusion protein shows specific antigenicity.

Study on the rhythm of urine iodine level of children aged 8-10 in Chongqing city / 中国地方病学杂志

Objective To undemtand the rhythm of urinary iodine level of children aged 8-10 in Chongqing city.Methods In April 2008,using the stratified random sampling method,we sampled 60 children aged 8-10 in a lodging primary school in Chongqing(20 per age group,half male and half female),the urine samples were collected in the morning and at 10:00,12:30,16:00,iodine in urine was detected by method of Ce and arsenic catalytic speetrophotometry(WS/T 107-2006).The difference of the urinary iodine level was compared by age,sex and time of day.Results The median urinary iodine of 60 children was 265.07μg/L on the overall.Irrespective of the stratification factors,excluding morning urinary iodine(366.75μg/L)and urinary iodine at 10:00(338.30 μg/L),the urinary iodine between 12:30(235.15μg/L)and 16:00(251.50μg/L)was not significant(all P>0.05),statistically significant differences(all P<0.05)were found between any two.The urinary iodine of 8-year-old group at different times of the day was significantly different(all P<0.05),except between morning urinary iodine (298.90 μg/L)and at 10:00,16:00(279.00,286.59 μg/L),between urinary iodine at 10:00 and 16:00(all P>0.05).The 9-year-old group's urinary iodine were not significantly different between morning urine(366.15μg/L)and 10:00(368.10 μg/L),and between 12:30(244.00 μg/L)and 16:00(186.30 μg/L,all P>0.05),significant differences were faund at other times of the day(all P<0.05).The 10-year-old group of urinary iodine changed very little before 12:30 (382.85,449.60,337.00 μg/L, all P > 0.05 ), followed by rapid decline to 16: 00 (269.35 μg/L), and compared with the morning urine and 10:00, there was significant difference(all P < 0.05).Regardless boys or girls, the urinary iodine at different times qf the day was significantly different (all P < 0.05),except between morning urinary iodine(337.32,309.28 μg/L) and at 10:00(316.15,288.27 μg/L), between urinary iodine at 12:30(251.18,211.45 μg/L) and 16:00(235.02,211.45 μg/L, all P > 0.05). Conclusions The change of urinary iodine level in children aged 8 - 10 was not obvious before noon, changes can be seen in the afternoon.Urinary iodine level before 10:00 is indicative.

Analysis of environmental fluoride of the coal-burning endemic fluorosis areas in Chongqing / 中国地方病学杂志

Objective To find out the distribution pattern of environmental fluoride in the coal-burning endemic fluorosis areas to provide scientific evidence for establishing prevention and remedial measures in Chongqing. Methods According to historical data in Chongqing In 2008, 4 endemic villages(Lingyun and Lizi Villages of Wushan County, and Taiping and Daqing Villages of Pengshui County) and 2 non-endemic villages (ShuangLou and XianLong Villages of Yongchuan County) were investigated. Dental fluorosis of children in 8 to 12 year old and residents over 16 years of age for clinical skeletal fluorosis were examined in four endemic villages. Five households from each of 6 villages were taken, where 500 g of coal, mixed clay with coal, mixed coal of soil, coal cinder, soil were sampled; 15 people were taken in each village, each household gathering 500 g of corn, rice, potatoes, vegetables, grain and vegetable, 100 g of dried pepper and 250 ml of drinking water were sampled from 15 families of each village. Household drinking water samples were collected 1, each 250 ml. For those having tea-drinking habit, each household was collected 50 g of tea and 600 ml of drinking tea, the amount of fluoride were determined. Indoor and outdoor air was collected and measured in 5 households in each village. Results The detected rate of dental fluorosis of children in endemic areas was 74.65% (736/986). The detected rate of skeletal fluorosis of adult was 7.20%(736/986). The average fluoride content of coal, mixed clay with coal, mixed coal of soil, cinder coal, soil in the endemic villages was (310.56±209.46), (360.51±224.96), (293.62±65.15), (186.59±133.66), (497.54±294.70)mg/kg. The average fluoride content in non-endemic villages was (48.68±10.62), (275.66±62.69), (152.20±34.43), (209.14±188.66),269.98±58.21)mg/kg. The fluoride content level of endemic villages was significantly higher than that of non-endemic villages(t=7.67,31.54,5.82, 5.82, all P<0.05). The average fluoride content of drinking water, corn, pepper, flee, potato and vegetable in the endemic villages was (0.30±0.14)mg/L, (1.83±2.67), (23.50±91.80), (0.77±0.25), (0.44±0.11), (0.48±0.18)mg/kg, The average fluoride content in non-endemic village was (0.18±0.06)mg/L, (2.21±0.46), (2.82±2.51), (1.31±0.21), (0.64±0.41), (1.10±0.77)mg/kg. The fluoride content in drinking water and pepper in the endemic villages was significantly higher than that of the non-endemic villages(t=7.79, 2.33, all P<0.05). The fluoride content of rice, potato and vegetable in the non-endemic villages was significantly higher than that of the endemic villages(t=39.29,4.69,4.01, all P<0.05). There was no significant difference of fluoride content of tea and drinking tea between endemic villages[(99.41±55.83)mg/kg, (1.59±0.91)mg/L] and non-endemic villages[(79.95±43.78)mg/kg, (1.80±1.16)mg/L, t=1.01, 0.27, all P>0.05]. The amount of drinking tea in the endemic village[(1.45±0.68)L/d] was higher than that in non-endemic village[(1.00±0.47)L/d, t=4.27, P<0.05]. The average fluoride content of indoor air in the endemic village[(12.77±8.08)μg/m3] was higher than that in non-endemic village [(1.16±1.08)μg/m3, t=9.49, P<0.01]. There was no significant difference of fluoride content of outdoor air between endemic village and non-endemic village[(1.10±1.57), (0.39±0.31)μg/m3, t=2.01, P>0.05)]. Conclusions The fluoride source of coal-burning endemic fluorosis areas are coal and mixed coal of soil in Chongqing. Fluoride enters into human bodies mainly via respiratory, not from food. Although fluoride is rich in pepper, people don't eat it, so reducing the fluoride content in indoor air is the principle measure. Drinking tea may be was one factor of endemic fluorosis, which needs to be further studied.