| Fluoride has been classified as possible trace element and an essential nutrient by World Health Organization and United States National Academy of Sciences. As any other trace element, adverse effects on human health would have occurred if the intake of fluoride either at an improperly low or high levels, manifesting of deficiency or toxicity. Of which, the dose-response relationship between the two levels of intake appears to be a U-shape curve. According to the historical documents, clinical evidences of skeletal fluorosis were found among residents as early as Xia Dynasty in China (4000 years ago). As described in a book《Yang Sheng Lun》(On a Healthy Lifestyle) by Jikang (During Weijin Period, AC 232-262), "Chi Ju Jin Er Huang", meaning that dental fluorosis had been found among people who lived in Shanxi region, where had long been identified as one of the most severe endemic areas of fluorosis in China. However, the systematic studies on the endemic fluorosis had just started in the early 20 century, in particular, after the founding of the Peoples' Republic of China. Studies on the etiology, epidemiology and prevention of dental and skeletal fluorosises indicated that the main cause of dental flurorsis and skeletal fluorosis was due to the exposure of high fluoride in drinking water in most endemic areas. In 1933, Dean and his colleagues studied the relationship between fluoride in drinking water and dental fluorosis, and dental caries. The results indicated that, when fluoride in drinking water reached up 1.00mg/L, the prevalence of dental caries was 10%, which was only one half found in the area with higher fluoride in drinking water; and the dental fluorosis found was categorized as mild type with neither significant affect the beauty and nor the general health. The results of Dean's study provided a scientific basis of fluoridation of water. However, Dean's study mainly concerned about fluoride in drinking water, and other sources of fluoride intake had not been taken into account at that time. In fact, the prevalence of dental fluorosis significantly increased after having the water fluoridated in many areas, such as Guangzhou, Guangdong Province, China and Hongkong, SAR, China. In the recent decades, a huge number of studies on the adverse effects of fluoride on dental, skeletal and other organs or systems, and the fluoridation for dental caries prevention were carried out and reported. Unfortunately, there was little information in respect with the characterization of the dose-response relationship between the exposure, particularly the total intake of fluoride, and the adverse effects on human health. Therefore, further studies on the relationship among the total intake of fluoride through a variety of sources and its health outcomes by using different end-points reflecting internal exposure and biological effects are urgently needed. This study was carried out with the collaboration of Jiangsu Province CDC and Sihong County CDC, and supported by The Association of Jiangsu Province for Endemic Disease Control and Prevention (Project No.: X200327). In this study, epidemiological method was used to investigate the total intake of fluoride, fluoride levels in drinking water; the biological monitoring of serum fluoride, urine fluoride; and the end-points of effects, i.e., dental fluorosis, skeletal fluorosis, children's IQ, and dental caries are used as variables of exposures. The doe-response relationship between the exposure to fluoride and the effects on human health was assessed; and the acceptable rang total intake dose (ARTID) of fluoride was recommended based on the study. The reliability and feasibility of the recommendation were taken into account, and the health impact will be followed-up in the areas studied.An extensive epidemiologic study was carried in Wamiao and Xinhuai villages at Sihong county, Jiangsu Province. Wamiao village, a severe endemic fluorosis area, with an average of fluoride in drinking water at 2.47(0.77mg/L (ranged 0.50-4.50 mg/L, is located in the nort...
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