The differences of brick-tea fluorosis of four ethnic in China

Abstract

Objective To investigate the differences of fluorosis of Tibetans, Mongolians, Kazakhs and Han in drinking tea type fluorosis areas. Methods In Guoluo Autonomous Prefecture of Qinghai Province, Hulunbuir City of Inner Mongolia Autonomous Region and Ahay Prefecture of Xinjiang Autonomous Region, two counties were selected in each province respectively, and 3 - 4 diseased townships were selected from each county. People 16 years and older of Tibetans, Mongolians, Kazakhs and Han were examined. A questionnaire survey of endemic fluorosis was conducted, the survey contents included general characteristics, average daily brick tea intake; drinking water, brick tea and urine were collected and used for analysis; forearm, lumbar spine and pelvisof subjects were examined by Portable DR. Water fluoride, ion selective electrode （WS/T 89-2006）. X-ray diagnosis brick tea fluorine and urinary fluoride were detected by of skeletal fluorosis was based on ＂Endemic Skeletal Fluorosis Diagnostic Criteria＂ （WS/T 192-2007）, and epidemiological and clinical descriptive information were combined. Results The total number of respondents was 1 703. The numbers of respondents in Tibetan, Mongolian, Kazak and Han were 525, 328, 305 and 545, respectively. In the four ethnic, average daily brick tea intake, fluoride content in drinking water, fluoride content in brick tea, average daily fluoride intake of brick tea, urinary fluoride content were 2 758.42 ml, 0.88 rag/L, 2.76 mg/L, 8.77 mg and 1.75 mg/L. Average daily brick tea intake, fluoride contents in drinking water, fluoride contents in brick tea, average daily fluoride intake of brick tea, urinary fluoride contents in Tibetan, Mongolian, Kazak and Han were 3 304.58, 2 170.42, 2 476.34, 1 583.93 ml, 0.27, 0.88, 1.04, 0.35 mg/L, 2.91, 1.66, 3.14, 0.93 mg/L, 10.17, 4.14, 9.22, 2.66 mg, 2.17, 1.41, 3.37, 1.15 mg/L. The differences of average daily brick tea intake, fluoride content in drinking water, fluoride content in brick tea, average daily fluoride intake of brick tea and urinary fluoride content between groups were statistically signifieant（F = 10.639, 50.498, 25.371, 10.800, 166.852, all P 〈 0.05）. The average detectable rate of X-ray skeletal fluorosis was 27.25% （399/1 464）. The X-ray detectable rate of skeletal fluorosis of Tibetan, Mongolian, Kazak and Han were 43.55% （ 179/41 t ）, 21.90% （60/274）, 3.22% （98/295） and 12.81% （62/484）, respectively. The detectable rate of skeletal fluorosis of males [30.70% （175/570）] was higher than that of females[ （25.06% （224/894）, χ2 = 5.596, P 〈 0.05]. The differences of detectable rate of skeletal fluorosis was statistically significant in different age groups of Tibetan, Mongolian and Han（χ2 = 50.423, 8.899, 18.676, all P 〈 0.05）. Conclusions Significant differences of tea type finorosis prevalence are found in different ethnic population. Compared with Mongolian, Kazak and Han, the detectable rate of skeletal fluorosis is higher and the condition of skeletal fluorosis is more serious in Tibetan, which is associated with higher fluoride exposures through brick tea. However, the skeletal fluorosis detectable rate of Kazakh is significantly lower than that of the Tibetan population buf both have similar level of fluoride exposure. It is demonstrated that non-exposure factors may be involved in the mechanism of tea type fluorosis. Key words: Fluorosis, dental ; Tea; Urine ; Minority groups