ABSTRACT
Objective To understand the status of total fluoride intake for persons over 16 years old after implementation of comprehensive prevention and control measures in historical severe diseased areas of coal-burning-borne endemic fluorosis in Guizhou Province.Methods In 2017,a total of 3 villages were selected as survey sites in Hehua,Jifeng and Jiping villages,which were heavier and did not meet the standards for elimination of the disease areas.Dental fluorosis of all children aged 8-12 were examined in these three villages.In each village,10 households were selected and average daily intake of staple foods,vegetables and drinking water per person over 16 years of age were surveyed.Samples of corn,rice,dried pepper,drinking water,and indoor air were collected and the content of fluoride was measured,and total fluoride intakes for adults were calculated.The survey results were compared with the survey data of 2006.Results The detection rates of dental fluorosis of children aged 8-12 in Hehua,Jifeng and Jiping were 16.86％ (29/172),17.90％ (29/162),7.94％ (10/126),respectively,and the differences were statistically significant compared to those of 2006 [94.32％ (216/229),100.00％ (72/72)、99.63％ (267/268),x2 =247.97,136.95,345.13,P ＜ 0.01].The fluorosis indices were 0.36,0.40,and 0.12,respectively.In the three villages,the medians of fluoride in drinking water were 0.040,0.029 and 0.033 mg/L.The staple food was rice,and their medians fluorine content were 0.019,0.016,and 0.015 mg/kg,respectively,which decreased 99.89％,99.96％,99.95％,compared with those of 2006 (the staple food was corn,with medians of 17.520,36.620 and 27.770 mg/kg).The medians of fluorine in dried pepper were 2.09,1.97 and 0.35 mg/kg,respectively,which decreased 99.59％,99.81％,99.96％,respectively,compared with those of 2006 (514.21,1 035.29,947.78 mg/kg),the differences were statistically significant (Z =2.079,2.542,2.449,P ＜ 0.01).No fluoride was detected in indoor air samples 24 hours a day.The average daily intake of fluorine per person over 16 years in the three villages were 0.304,0.279,0.273 mg,which decreased 98.45％,99.18％ and 99.00％,respectively compared to those of 2006 (19.564,33.837,27.224 mg).Conclusion Total fluoride levels are significantly lower in people over 16 years of age in the historical severe disease areas of coal-burning-borne endemic fluorosis in Guizhou Province.