2 estimated to be 2–3 tons annually. Some families even burn more than 500 kg in 15 days [9]. Skeletal ﬂuorosis (SF) is a chronic metabolic bone disease that occurs when abnormally large amounts of ﬂuoride accumulate in bone tissue. Because bone growth and remod- eling occur over a human’s lifespan, SF can progressively worsen with overexposure to high ﬂuoride levels [10]. A variety of conditions are associated with SF including osteosclerosis, osteomalacia, osteoporosis, and secondary hyperparathyroidism; severity is also varied, ranging from mild joint pain to crippling disabilities and severe bone deformations [10, 11]. Typical signs and symptoms include aches and pains, limited joint movement, knock-knees, bowing of legs, and spinal curvature. Clinical symptoms may not be present until SF cases become advanced. Radiological changes are discernable at earlier stages of disease revealing irregular thickening and high density of bones upon X-ray examination [10]. Epidemiological studies have historically focused on SF among adults residing in ﬂuorosis endemic areas [3, 11– 14]. Adults living in these areas should theoretically have longer cumulative exposure to excessive levels of ﬂuoride from their environments and thus higher prevalence than children. Despite limited lifetime exposure to ﬂuoride among juvenile populations, children living in endemic ﬂuorosis areas also suﬀer from SF [15, 16]. The eﬀects of various levels of ﬂuoride intake, speciﬁcally persistent exposure to high levels of ﬂuoride, on rapidly developing bones in young children are not well understood. Fluoride can alter accretion and resorption of bone tissue or interrupt the homeostasis of mineral metabolism in bone [16]. Increased metabolic turnover of bone, impaired synthesis of bone, or ﬂuoride accumulation in the crystal lattice of skeletal tissue may all be important mechanisms for how ﬂuoride aﬀects bone tissue in rapidly growing children. Furthermore, only a few endemic ﬂuorosis studies have focused on the prevalence of SF among children or adolescents [16, 17]. Previous reports of juvenile SF in southwestern China suggest that children diagnosed with SF tend to be young, exhibit bone deformations, and have X-ray signs of mixed type bone transformation [17]. A more in-depth understanding of the prevalence and severity of SF among juvenile populations is required in order to plan control eﬀorts and reduce ﬂuorosis- related disease and disability in highly endemic areas. Dental ﬂuorosis (DF) is a permanent hypomineralization of tooth enamel caused by an overexposure to ﬂuoride dur- ing tooth development. DF aﬀects teeth during permanent tooth formation, which usually occurs in childhood between the ages of 6 months to 5 years. After permanent teeth erupt into the oral cavity, signs of DF are considered permanent without cosmetic dental repair. Typical signs of DF include yellowing of teeth, white spots, mottling of enamel, and brown staining in severe cases. Enamel damage resulting from DF can be viewed on the permanent teeth of children as well as adults. Accordingly, epidemiology of endemic ﬂuorosis among children is commonly reported in terms of prevalence and severity of DF of children living in endemic ﬂuorosis regions [2, 4, 10, 11]. Although other investigations have reported on the prevalence of DF in regions of China, Journal of Environmental and Public Health none have focused on our area of interest, Zhijin County. Since ﬂuorine exposure is highly correlated to the immediate environment in which a person lives, speciﬁc estimates for Zhijin County are necessary in order to understand the extent and severity of endemic ﬂuorosis aﬀecting this area. The present study is among the ﬁrst to report SF prevalence among children/adolescents living in a coal- burning endemic ﬂuorosis area. It was designed to (1) assess the prevalence of SF and DF among children from indoor burning of coal, and (2) describe the pathogenic state of SF among children and adolescents residing in a severe endemic ﬂuorosis area. 2. Methods 2.1. Design. A cross-sectional survey was conducted in a rural, heavily polluted region of Zhijin County, Guizhou, China, between October and December 2004. 2.2. Participants. Participants included children who were studying at all the 9-year compulsory education schools in the rural area: Guohua, Hehua, Lianhe, Niotong, and Yanzai primary schools. Students attending these ﬁve schools have very similar living conditions and diﬀer minimally in terms of lifestyle, parental education level, socioeconomic status, and medical care. The study proposal was approved by the Guiyang Medical College Internal Review Board. 2.3. Sampling. To save time and reduce the cost, a cluster sample design was used. It produced a representative sample of students in grades 1–9 who enrolled in the ﬁve choosing primary schools. A total of 1616 students aged 7–16 years participated the study. Data collection took place in the schools during the period of Education Examination by Guizhou Bureau of Education, a time when schools typically have high attendance rates. The study investigation team and primary school teachers supervised children during data collection. Screening questions were explained to the children in the younger age range at the time of the survey. Selected students completed a questionnaire that included questions about their lifestyle and exposure to burning coal. For this study, living in a household that (1) burned coal, (2) used an open-burning style stove, or (3) baked/dried foodstuﬀs over a coal stove was considered an SF risk factor. Based upon responses, 370 students were classiﬁed as high- risk for SF and further examined for SF. 2.4. Measures 2.4.1. Diagnosis of Skeletal Fluorosis. Children were exam- ined and X-rays were taken at their own school. Directed by the technologist of the Radiology Department of Guiyang Medical College, X-rays of each child’s pelvis region and lower limbs were taken by the technician of the Radiology Department of Zhijin Traditional Chinese Medical Hospital. An endemic SF specialist examined all X-ray ﬁlms and made oﬃcial diagnoses. X-ray checkpoints were the pelvis and right lower limbs (ankles were included, if necessary).