Analysis of surveillance results of dental fluorosis of children in drinking water-borne fluorosis areas of Qinghai Province from 2009 to 2017.

Objective To analyze the operation of water improvement projects in drinking water-borne fluorosis areas of Province and the trend of dental fluorosis in children aged 8 to 12 years, and to evaluate the effects of prevention and control measures comprehensively, so as to provide basis for improving prevention and control strategies. Methods In 2009 - 2017, according to the Qinghai Drinking Water Endemic Fluorosis Surveillance Program, four project counties of Huangyuan, Minhe, Hualong and Guide were selected in Province. Three villages in each project county were selected according to their mild, moderate and severe conditions, and monitored the operation of water improvement projects, water fluoride content and dental fluorosis among children aged 8 to 12-year-old in each diseased village. Results In 2009 - 2017, the normal operation rate of water improvement projects increased from 2/8 to 7/8; the batch operation rate of the projects decreased from 5/8 to 1/8; the number of abandoned projects decreased from 1 to 0; the number of people covered by qualified water fluoride increased from 9 962 to 80 760 people; there was no significant difference in water fluoride content between different years (F = 0.758, P > 0.05). The total detection rate of children′s dental fluorosis was 33.01% (1 812/5 489) from 2009 to 2017, the index of dental fluorosis was 0.65, and the epidemic intensity was slightly prevalent; the detection rate of children′s dental fluorosis was 30.02% (951/3 168) in villages with normal operation of water improvement projects and qualified water fluoride content, the index of dental fluorosis was 0.58, and the epidemic intensity was marginal; the detection rate of children′s dental fluorosis was 32.72% (583/1 782) in villages with abnormal operation of water improvement projects or excessive fluoride, the index of dental fluorosis was 0.66, and the epidemic intensity was slight; the detection rate of children′s dental fluorosis in villages without changing the water was 51.58% (278/539), and the index of dental fluorosis was 1.04, belonging to the moderate epidemic intensity; the detection rate of children′s dental fluorosis in villages without changing the water was significantly higher than that in villages with normal operation of water improvement projects and qualified water fluoride content (χ2 = 102.30, P < 0.01). Conclusions The water improvement project in drinking water-borne fluorosis areas is running well and the operation rate is increasing year by year. The detection rate of dental fluorosis in children aged 8 - 12 years old in villages with normal operation of water improvement projects and qualified water fluoride content was significantly lower than that in villages without changing the water. The monitoring of fluorosis and the maintenance of water-renovation projects should be strengthened, and the problem of drinking water for residents in villages without changing the water should be resolved as soon as possible. Key words: Fluorosis, dental; Drinking; Dental fluorosis index; Epidemic intensity