The investigation of prevalence state of drinking water-born endemic fluorosis in Shaanxi

Objective To explore the prevalence state of endemic fluorosis associated with and evaluate control effects in Shaanxi. Methods By stratified sampling, dental fluorosis in children aging 8～12 years and skeletal fluorosis in adults aging above 16 years were examined. X-Ray films were taken in subjects with suspicious skeletal fluorosis. Fluoride levels in drinking water and children's urine were determined. Results In 20 counties, the dental fluorosis rate was 38.64%, and 75.56% in severe fluorosis areas. The skeletal fluorosis rate were 11.76%, and 31.73% in the severe fluorosis areas. The positive rate of X-Ray detection was 63.61%. The fluoride levels in 62.96% of water samples exceeded criterion established by the Ministry of Health of the People's Republic of China. The fluoride levels in 55.15% of water samples of over-criterion were beyond 2.1 mg/L. The median of fluoride levels in children's urine was 2.00 mg/L, and 4.58 mg/L in the severe fluorosis areas. As compared with 1980, the dental fluorosis rate descended in varying degrees in 85% of 20 counties, among which 5 counties had become non-endemic fluorosis areas. Average decreased ranges of the dental fluorosis rate reached 46.14% in 20 counties. Conclusions The prevalence of endemic fluorosis associated with drinking water is comparatively serious in Shaanxi. Prophylactic measures, such as improving water quality, have achieved great results.