Investigation on the epidemic status of drinking-water type endemic fluorosis in Henan province in 2011

Objective To grasp the current status of drinking-water type endemic fluorosis in Henan province,so as to provide basis to future prevention and cure.Methods According to Technical Scheme for Endemic Disease Control in Henan province in 2010,10 counties(districts) with drinking-water type endemic fluorosis were selected.10 defluoridation projects were selected by random sampling in every county for surveillance,3 affected villages were divided into mild,moderate and severe,which were randomly selected by stratified sampling method from each category of the area to carry out the monitoring of endemic fluorosis.The fluoride level in water and dental fluorosis of children aged from 8 to 12 were examined.Results Among 100 investigated water improvement projects in the 10 counties,99 were running normally,fluoride level in water exceeded the standard,accounting for 21%(21/100).A total of 30 affected villages were investigated,among which the drinking water quality of 8 villages were improved,and all the fluoride content of defluoridation projects were normal.In the 8 improved-water villages,detection rate of dental fluorosis of children aged 8 to 12 was 52.71%(496/941),defect rate was 5.84%(55/941),and dental fluorosis index was 1.19 and the prevalence was middle.In the 22 unimproved-water villages,detection rate of dental fluorosis of children aged 8 to 12 was 47.34%(1015/2144),defect rate was 13.29%(285/2144),and dental fluorosis index was 1.15,the prevalence was medium.Conclusions The fluoride level of defluoridation projects exceeded the standard seriously,the fluorosis harm is still heavy in Henan,so scientific verification of water-improving project and work acceptance should be enhanced,preclude the use of unqualified project,water quality monitoring should be launched regularly,and the project of standard-exceeding of water quality should be improved promptly.