Investigation on drinking status of border-sale tea in the key endemic areas of tea drinking type endemic fluorosis in Gansu Province / 中华地方病学杂志

ABSTRACT

Objective:To comprehensively investigate the epidemic scope, geographic features and threatened population of tea drinking type endemic fluorosis in Gansu Province.Methods:From June 2019 to December 2020, according to the "2019 Investigation Plan on the Epidemic Situation of Tea Drinking Type Endemic Fluorosis" and the relevant information about the living habits of residents in cities (prefectures) in Gansu Province, 12 counties (cities) in 4 cities (prefectures) of Gannan, Wuwei, Jiuquan and Zhangye, which had the habit of drinking border-sale tea, were selected as the survey sites. The survey contents included temperature, altitude, the number of townships (towns), the number of administrative villages (residents' committees, referred to as villages), the total population under its jurisdiction, ethnic composition, production methods, drinking condition of border-sale tea, fluoride content of tea, etc. The fluoride content of tea was tested according to "The Fluoride Content of Brick Tea" (GB 19965-2005), and the evaluation of whether the fluoride content exceeded the standard (> 300 mg/kg) was carried out.Results:The annual average temperature of the survey sites ranged from 0.2 to 12.7 ℃, except for Zhouqu County, the annual average temperature of the other 11 counties (cities) was < 10 °C; the average altitude ranged from 1 200 to 4 874 m, and there were 6 counties (Maqu, Tianzhu, Subei, Sunan, Aksay and Luqu) with an altitude > 3 000 m. The total population of the 12 counties (cities) was 1 051 843, of which 492 597 (46.83%) were ethnic minorities who had the habit of drinking border-sale tea; among them, there were 474 620 Tibetans, 10 152 Yugurs, 4 660 Mongolians and 3 165 Kazaks. In 860 villages of 125 townships (towns), a survey was conducted on drinking condition of border-sale tea, and the survey rate was 79.48% (860/1 082); the drinking border-sale tea rates of villages and families were 57.67% (496/860) and 42.41% (3 658/8 625), respectively. From the perspective of production methods, the drinking border-sale tea rates of villages and families in the pastoral counties such as Aksay, Subei, Maqu, Luqu and Sunan, as well as in the semi-agricultural and semi-pastoral county of Tianzhu, were all > 95%. A total of 3 664 tea samples were tested, with an average fluoride content of 481.33 mg/kg. There were 2 588 tea samples with a fluoride content > 300 mg/kg, accounting for 70.63% (2 588/3 664).Conclusions:There are still a large number of populations who drink border-sale tea in Gansu Province, mainly distributes in the low-temperature and high-altitude pastoral counties such as Aksay, Subei, Maqu, Luqu and Sunan. The ethnic group most threatened by tea drinking type endemic fluorosis is Tibetans.