Evaluation of the effectiveness of prevention and control measures in drinking water-born endemic fluorosis areas after water improvement in Xuchang City, Henan Province / 中华地方病学杂志

ABSTRACT

Objective To evaluate the effectiveness of prevention and control measures in drinking waterborn endemic fluorosis areas after water improvement in Xuchang City,Henan Province.Methods In the drinking water-born endemic fluorosis areas of Xuchang City,Henan Province,15 villages were selected based on the following parameters:the unimproved water group,the water improvement time ＜ 3 years group,the water improvement time 3-5 years group and the water improvement time ＞ 5 years group,using a multi-stage random sampling method.In those villages,the concentration of urinary fluoride was tested by the ion selective electrode method on 30 children selected by every village,and Deans method was applied for diagnosis of dental fluorosis on all students age 8-12 years old of the 15 villages.Results The dental fluorosis prevalence rates of the unimproved water group,the water improvement time ＜ 3 years group,the water improvement time 3-5 years group and the water improvement time ＞ 5 years group were 53.57％ (120/224),63.64％ (98/154),37.30％ (47/126) and 22.99％ (40/174),respectively,and the urinary fluoride geometry means were 2.10,1.30,1.07 and 1.02 mg/L,respectively.The prevalence of dental fluorosis was significantly different between the improvement time 3-5 years and the unimproved water groups (x2 =8.56,P ＜ 0.008),and between the improvement time ＞ 5 years and the unimproved water groups too (x2 =38.10,P ＜ 0.008).The geometric mean of urinary fluoride was significantly different between the improvement time ＜ 3 years and the unimproved water groups (q =5.66,P ＜ 0.01),between the improvement time 3-5 years and the unimproved water groups (q =8.14,P ＜ 0.01),and between the improvement time ＞ 5 years and the unimproved water groups (q =8.28,P ＜ 0.01).The level of urine fluoride in children was positively correlated with the fluoride content in the village (r =0.659,P ＜ 0.01),and was positively correlated with dental fluorosis index too (r =0.758,P ＜ 0.01).Conclusions The content of urinary fluoride has decreased significantly in less than three years after water improvement in drinking water-born endemic fluorosis areas.The incidence of dental fluorosis in children is related to the improvement of water supply.The longer the time of the water improvement,the more obvious the detection rate decreased more obvious.