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.