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.

Objective To propose prevention and control strategy against iodine deficiency disorders to prevent new cases of endemic cretinism from occurring. Methods In April and August 2007, all the suspected cretinism patients born after the first of January, 1997 were searched for in 16 counties from Lhasa, Shannan, Nyingchi, Qamdo and Xigaze. Meanwhile, 60 children aged 8-10 years were selected in each of the two rural villages of each county chosen. Goiter was examined using palpation and B-ultrasound, urinary iodine was determined, inteligence quotient(IQ) was tested; 30 women of childbearing age from each village chosen underwent urinary iodine test and household salt semi-quantitative detection. Results No new cases of endemic cretinism had been found; Palpation identified goiter at 4.5% (257/5680) in children, B-ultrasound revealed a rate of 4.7% (258/5433). Median of urinary iodine was 159.4 μg/L, the averaged IQ was 78.3±14.5; women of childbearing age had a median urinary iodine of 70.2 μg/L. The coverage rate of iodized salt was 52.8%. Conclusions Goiter rate in children, urinary iodine level meet the standard set for the elimination of iodine deficiency disorders; however, the low IQ children, low coverage of iodized salt and the level of urinary iodine in women of childbearing age are less than desirable. Iodine deficiency disorders prevention and control need to be strengthened.

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.