RESUMO
Objective To understand current prevalence of fluorosis, of drinking tea type in Pengyang County of Ningxia to offer scientific basis for preventing and curing, monitoring, health education. Methods Four towns were chosen as investigating spots in Pengyang County of Ningxia in 2007, from each 50 children aged 8-12 year old and 50 adults who either had tea or did not were investigated. Dean method was used to measure dental fluorosis of children and adult; meanwhile fluoride content in water, urine and drinking tea was tested using the fluoride ionic electrode method and that in brick tea using water immersion electrode method. χ2 testing, analysis of variance, u test, q test were performed. Results In adult drink tea group, control group, and children, the detaction rate of dental fluorosis were respectively 24.75%(99/400),9.5%(38/400)and 15.96%(71/445), obviously higher in drink tea group than the control group(χ2= 32.73, P<0.05). Urine average concentration of fluoride was (3.38±2.37), (2.09±1.33 ). (1.41±0.67)mg/L, obviously higher in drink tea group than the control group(u= 9.49, P<0.05). In 4 investigation spots tea fluoride averaged at (3.63±2.05)mg/L, fluoride content in drinking water was averagely (1.01±0.49) mg/L, with that of Wangwa Town [(1.31±0.33)mg/L] exceeding the national standard for drinking water (1.0 mg/L), where dental fluorosis rate was higher and fluoride content was higher than that in 3 other investigation spots (P<0.05). Conclusions Residents in Pengyang County in Ningxia who drink brick tea can cause accumulation of fluorine to poison in Ningxia, leading to fluorosis of drinking tea type; Wangwa Town have both drink tea and water fluorine poison.
