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Objective To grasp the prevalence of drinking brick-tea type fluorosis in Tibet,and to provide scientific basis for the development of prevention and control strategies.Methods Twelve counties were selected from 7 regions in Tibet.In accordance with the "Drinking Brick-Tea Type Endemic Fluorosis Monitoring Program",a total of 46 administrative villages were selected as survey points using the cluster stratified sampling method.Household water samples,tea-water samples and adult urine samples were collected,and household fluorine intake status and incidence of skeletal fluorosis in adults over 16 years old were investigated.In the rural grade primary school where the village children were concentrated,all children aged 8-12 were selected,urine samples were collected,and the prevalence of dental fluorosis was investigated.Fluoride contents in tea,water,and urine were detected by ion selective electrode method.The dental fluorosis and skeletal fluorosis were examined and judged according to the "Diagnosis of Dental Fluorosis" (WS/T 208-2011) and the "Diagnostic Criteria for Endemic Skeletal Fluorosis" (WS 192-2008),respectively.Results A total of 46 villages in 12 counties were investigated,1 992 of water samples,1 662 of tea samples,664 of children urine samples,3 186 of adult urine samples were detected;547 children aged 8-12 were examined dental fluorosis and 3 196 adults were examinea skeletal fluorosis,respectively.The water fluoride contents in all the investigated villages were less than 1.0 mg/L;the average fluoride content in brick-tea water was 6.12 mg/L,within the range of 0.11-84.00 mg/L,and the average daily brick tea fluorine intake of residents was 24.98 mg.The geometric mean of urine fluoride in children and adults was 0.76,2.28 mg/L,respectively.The prevalence rates of dental fluorosis in children and skeletal fluorosis in adults over 16 years old were 31.81％ (174/547) and 48.59％ (1 553/3 196),respectively.The children dental fluorosis index was 0.60.The detection rate of skeletal fluorosis in adults aged 36-45 was 13.37％ (69/516).Conclusions The prevalence of drinking brick-tea type fluorosis in Tibet is serious and widely distributed.In particular,the prevalence rate of skeletal fluorosis in adults is relatively high,while that of dental fluorosis in children is relatively mild.The prevention and control of drinking brick-tea type fluorosis in Tibet brook no delay.
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Objective To monitor the situation of iodine deficiency disorders (IDD) in Tibet,and to provide a background information of iodine nutritional status of residents before adjustment of iodine concentration.Methods According to the method of population proportionate sampling (PPS),27 counties were selected to carry out IDD surveillance.One primary school was selected in each county.Forty children aged 8-10 from each primary school were sampled to examine thyroid volume,and edible salt samples were collected from their home to determine salt iodine.In addition,12 of the sampled children,15 pregnant women and 15 lactating women from three townships near the selected schools were chosen to detect urinary iodine.The methods of B-ultrasonography,oxidation-reduction titration (GB/T 13025.7-1999) and arsenic cerium catalytic spectrophotometry (WS/T 107-2006) were used to determine thyroid volume,salt iodine and urinary iodine,respectively.Results One thousand and eighty-one children aged from 8 to 10 were examined,and their goiter rate was 1.9％ (20/1 081).Seven hundred and fifty-eight salt samples were determined,and the median salt iodine level was 38.3 mg/kg and the consuming rate of qualified iodized salt was 88.1％(758/668).Meanwhile,urine samples of 522 children aged 8-10,267 pregnant women and 336 lactating women were also tested,and their median urinary iodine level was 166.1,132.7,138.1 μg/L,respectively.Conclusions The results show that the goiter rate and urinary iodine level of children aged from 8 to 10 have reached the national standard of IDD elimination (＜5％,100-300 μg/L),while the residents consumption rate of qualified iodized salt is still lower than the national standard (90％).In particular,the iodine nutrition of pregnant women is inadequate,which is lower than the national standard (urinary iodine 150 μg/L).It is still necessary to strengthen the monitoring of salt iodine as well as iodine nutrition in special groups in the future,and strengthen health promotion at the same time.
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Objective To find out the dynamics of drinking water borne endemic fluorosis in Tibet's, to evaluate the effect of control measures, and to provide a scientific basis for the timely adjustment of control strategies. Methods During september to october 2009, according to the "2008 Central Government Special Funds to Subsidize Local Public Health in Drinking Water Borne Fluorosis in Tibet", Xigaze Xietongmen and Nyingchi Zayu were selected as project counties, three project villages were selected with simple random sampling method in each county, the functioning of water improvement projects, drinking water fluoride content, children's dental fluorosis and adult skeletal fluorosis were investigated. Water fluoride was detected by the "standard examination methods for drinking water the non-metallic targets"(GB/T 5750.6-2006) determination of fluoride; urinary fluoride was tested by ion selective electrode (WS/T 89-1996); dental fluorosis was diagnosed using Deans method; adult skeletal fluorosis was diagnosed by "endemic skeletal fluorosis clinical diagnostic criteria" (WS 192-2008). Results Mean water fluoride was 0.18 - 0.34 mg/L in drinking water changed areas, and 0.70 - 2.13 mg/L in not changed areas; prevalence of dental fluorosis of children 8 - 10 was 50.78% (65/128), dental fluorosis index was 1.04,mean urinary fluoride was 1.64 mg/L in drinking water changed areas; prevalence of dental fluorosis of children 8 -10 years old was 80.65%(25/31 ) in not changed areas, dental fluorosis index was 1.50, mean urinary fluoride of children was 2.08; adult clinical skeletal fluorosis was 38.7%(104/269) in drinking water changed areas, the mean urinary fluoride was 1.61 mg/L, prevalence of skeletal fluorosis was 15.4% (18/117) in not changed areas, mean urinary fluoride was 3.54 mg/L. Conclusions The method of change the water to reduce fluoride decreases dental fluorosis to control levels, and severity is also reduced, urinary fluoride is decreased. However, the prevalence of skeletal fluorosis is higher than that of drinking water not changed areas.
