An evaluation of the effectiveness of prevention and control measures on coal- burning- borne endemic fluorosis in Guizhou Province

Objective To evaluate the effects of health education and improved stoves on control of coalburning-borne endemic fluorosis in Guizhou Province. Methods In 2014, according to the detectable rate of dental fluorosis of children aged 8 - 12 before implementing control measures, 11 counties were divided into three layers: low detection rate (detection rate was less than 60%), medium detection rate (detection rate from 60% to 90%) and high detection rate (detection rate was greater than 90%). One county was selected from each layer and two towns were selected in each county. According to the "Diagnosis of Dental Fluorosis" (WS/T 208- 2011), dental fluorosis of all children aged 8 - 12 was examined in all towns; At the same time, in the 2 villages in each town, 20 households and students of one class in grade 4 to 6 were selected to survey knowledge about prevention and control of coal-burningborne endemic fluorosis; and to survey the situation of improved stoves, drying and elutriation of corn and chillies, and related life behavior. Results The detectable rate of dental fluorosis of children aged 8 - 12 was 5.49% (198/3 607), 8.33% (72/864), 12.46% (179/1 437), and it was significantly lower than before implementing control measures [41.88% (931/2 223), 61.91% (4 863/7 855), 91.25% (2 439/2 673), χ2 = 1 166.43, 909.56, 2 508.96, all P < 0.01]. Correct answer rates of students about knowledge on endemic fluorosis were 78.03% (792/1 015), 84.93% (1 465/1 725) and 80.18% (910/1 135), the correct answer rates of knowledge were significantly higher than those before implementing control measures [23.19% (640/2 760), 47.41% (2 368/4 995) and 40.25% (3 405/8 460), χ2 = 947.96, 736.61, 644.69, all P < 0.01]. Correct answer rates of family householders about knowledge on endemic fluorosis were 86.75% (347/400), 95.25% (381/400) and 86.25% (345/400), the correct answer rates of knowledge were higher than those before implementing control measures [17.78% (80/450), 37.20% (279/750) and 25.27% (139/550); χ2 = 402.97, 359.49, 344.55, all P < 0.01]. The percentages of households whose stoves were qualified and can be used correctly to the total households were 96.25% (77/80), 96.25% (77/80) and 93.75% (75/80), and before implementing control measures [4.92% (348/7 078), 21.51% (7 461/34 693) and 6.73% (475/7 062)], and the differences were statistically significant (χ2 = 1 181.55, 262.63, 842.82, all P < 0.01). The percentages of households using clean energy in heating season to the total households increased from 0 (0/7 078), 0 (0/34 693), 0 (0/7 062) to 98.75% (79/80), 98.75% (79/80), 96.25% (77/80). The rates of the three counties whose inhabitants could bake the chillies correctly were 96.25% (77/80), 95.00% (76/80) and 97.50% (78/80), which were significantly higher than before implementing control measures [5.55%(5/90), 26.00% (39/150), 52.73% (58/110), χ2 = 139.52, 99.36, 45.64, all P < 0.01]. Who cooked chillies after washing were 93.75% (75/80), 95.00% (76/80), 93.75% (75/80), which were significantly higher than before implementing control measures [74.44% (67/90), 87.33% (131/150), 34.55% (38/110), χ2 =11.47, 3.91, 67.36, all P < 0.05]. Conclusion The effects of health education and improving stoves on coalburning-borne endemic fluorosis in the three counties of Guizhou Province are remarkable. Key words: Fluorosis; Coal; Health education; Improved stoves; Effect evaluation