Prevalence of tea-drinking type fluorosis in some regions of Qinghai province

  Objective  To examine the prevalence of tea-drinking related fluorosis in Hainan and Haidong prefecture of Qinghai province and to provide evidences for prevention and control of tea-drinking related fluorosis.

  Methods  We totally selected 55 administrative villages (one village in each town, 5 towns with different geographical location in each of all the 11 counties in the two prefectures) according to the regime of National Survey on Tea-Drinking Related Fluorosis. Then we recruited 60 adult residents (≥ 16 years) for urine fluoride detection and all children aged 8 – 12 years for dental fluorosis examination in each of the 55 villages during 2016; drinking water samples were also collected from the villages simultaneously. Fluoride concentration in water and urine samples were determined with ion selective electrode method; dental fluorosis was diagnosed using Dean′s index; and adults′ skeletal fluorosis was diagnosed based on Diagnosis Standard for Endemic Skeletal Fluorosis (WS192-2008).

  Results  The geometric means of fluoride in drinking water samples from Hainan and Haidong prefecture were all lower (0.29 mg/L and 0.25 mg/L) than the national standard (1.0 mg/l). The geometric means of fluoride in adult urine samples from Hainan (n = 800) and Haidong prefecture (n = 1 428) were 0.83 mg/l and 0.62 mg/L. The detection rate of dental fluorosis was 14.06% and 15.09% among the children in Hainan (n = 3 975) and Haidong prefecture (n = 2 677), with the prevalence indexes of 0.24 and 0.26. The prevalence rate of clinic skeletal fluorosis was 8.01% and 2.44% for the adults in Hainan (n = 1 484) and Haidong prefecture (n = 1 968), respectively.

  Conclusion  The prevalence of tea-drinking related fluorosis is generally at a low level and varies geographically in Hainan and Haidong prefecture of Qinghai province; the prevalence tea-drinking related fluorosis is relatively higher in Hainan prefecture than that in Haidong prefecture, indicating that health education on the risk of consumption of brick-tea with high fluoride should be promoted among the residents in the prefecture.