Investigation and analysis on epidemic status of tea-drinking-borne endemic fluorosis in Gansu Province from 2019 to 2020 / 中华地方病学杂志

ABSTRACT

Objective:To analyze the epidemic range of tea-drinking-borne endemic fluorosis in Gansu Province and accurately grasp the information of tea-drinking-borne endemic fluorosis patients, so as to provide basis for popularizing low fluorine brick tea and carrying out patient rescue and treatment.Methods:From 2019 to 2020, 12 counties (cities) in Gansu Province with a history of drinking brick tea were selected as the survey points according to the "Investigation Plan of Endemic Fluorosis of Tea Drinking Type in China in 2019" and the relevant information in Gansu Province. A cross-sectional survey was conducted in all villages with the habit of drinking brick tea (including the investigation of the fluoride content in drinking water, tea, the fluoride intake of the population, the dental fluorosis and urinary fluoride content of children aged 8 to 12, and the skeletal fluorosis and urinary fluoride content of adults), and the survey results were analyzed.Results:The survey covered 125 townships in 12 counties (cities), with 8 625 households in 860 villages. One thousand six hundred and seventy-two drinking water samples were collected, and the fluoride content in water ranged from 0.01 to 1.81 mg/L. Six villages with fluoride content > 1.0 mg/L were screened. A total of 3 664 tea samples were collected, the average fluorine content of brick tea was 481.33 mg/kg, and the fluorine content ranged from 31.88 to 1 643.40 mg/kg. There were 1 076 tea samples with fluorine content less than 300 mg/kg, and the qualified rate of fluorine content in brick tea was 29.37% (1 076/3 664). Among the 12 counties (cities), 92 townships and 496 villages were still drinking brick tea. The drinking rate of brick tea in villages was 57.67% (496/860), and the annual per capita consumption of brick tea was 1.21 kg. The average daily intake of tea fluoride in adults was 1.57 mg/d. In Maqu County, Aksai County, Tianzhu County and Sunan County, the daily intake of tea fluoride of adults in 31 villages of 13 townships was more than 3.5 mg, involving 5 272 households and 15 272 people. Sixty-five patients with dental fluorosis were found in the above 31 villages. The detection rate of dental fluorosis was 3.50% (65/1 856), mainly in very mild and mild cases. Urine samples were collected from 326 children. The median of urinary fluoride was 1.44 mg/L. The clinical investigation of skeletal fluorosis was carried out in 2 189 adults. X-ray examination of bones and joints was performed in 123 patients with definite clinical symptoms and/or signs of skeletal fluorosis. Seven cases of skeletal fluorosis were positive, the detection rate was 0.32% (7/2 189). Urine samples were collected from 83 adults. The median of urinary fluoride was 1.83 mg/L. Two villages with moderate disease were identified as Yehuwan Village in Anyuan Town of Tianzhu County and Nannigou Village in Zhuaxixiulong Town. Four villages in the mild diseased areas were identified as Daiqian Village in Zhuaxixiulong Town, Xiding Village in Dahonggou Town, Tuta Village in Danma Township of Tianzhu County and Annanba Village in Akeqi Township of Akesai County.Conclusion:Most of the endemic areas of tea-drinking-borne endemic fluorosis in Gansu Province have been under control, but the risk of tea fluoride exposure still exists in some areas, so it is urgent to take targeted prevention and control measures.