To understand the epidemiological prevalence of drinking-tea type fluorosis in Haidong Region, Qinghai Province, and provide scientific data for its prevention and control.

According to the investigation plan of drinking-tea type fluorosis in China, cross sectional survey was adopted to select 6 counties in Haidong Prefecture from May to July in 2016. Five townships were selected according to the eastern, western, north and south directions, 1 administrative village was randomly selected in each township (town) as the survey site. Water and brick tea samples were collected to test fluoride ion concentration; dental fluorosis in children aged 8 to 12 years and adult skeletal fluorosis were examined. Fluorine ion selective electrode was used to determine fluoridated fluoride (WS/T 106-1999), fluorine in urine (WS/T 30-1996) and fluorine content in brick tea (GB 19965-2005). Dental fluorosis was examined by Deans method. The diagnosis of skeletal fluorosis was referred to the "Diagnostic Criteria for Endemic skeletal Fluorosis" (WS 192-2008).

Fifty-seven drinking-water and 56 brick-tea samples were determined, the means of fluoride in drinking water and brick-tea were 0.25 mg/L and 724.71 mg/kg [which was significantly higher than the national standard (300 mg/kg)], respectively. Totally 1 207 urinary samples of children and 1 428 urinary samples of adults were determined, the geometric means of urinary fluoride of children and adults were 0.57 and 0.62 mg/L, respectively; 2 677 children and 1 968 adults were examined, the rate of dental fluorosis among children was 15.09% (404/2 677), its index was 0.26, the prevalence rate of clinic skeletal fluorosis among adults was 2.44% (48/1 968).

The fluoride content of brick tea in 6 counties of Haidong Prefecture of Qinghai is higher than that of the national standard. Local residents are still exposed to high fluoride brick tea, and health education and publicity should continue to be strengthened.

Fluorosis, dental; Tea; Skeletal fluorosis; Urine