Objective To study the relationship between the level of fluoride in urine and the prevalence of dental caries in children before and after the defluoridation, and to provide a basis for assessment of the effects of defluoridation projects and for control of dental caries.Methods Wamiao Village, in Jiangsu Province, a formerly severe endemic fluorosis area, was selected to carry out the study.All children aged 8-13 years old before the defuoridation were investigated from September to November in 2002, and children 8-10 years old who were born after the defluoridation were investigated from September to November in 2013.Urinary fluoride level of the children and the prevalence of dental caries were determined, and their relationships were analyzed.The urina sanguinis samples of children were collected in the morning, and the urine fluoride level was tested using the fluoride ion selective electrode.Dental caries diagnoses was referenced to Dental Caries.Results Totally children's urine samples were 236 and 68 respectively before and after defluoridation.Urinary fluoride level of the children was significantly decreased from (3.53 ± 1.81)mg/L (before defluoridation) to (1.39 ± 0.66)mg/L (after defluoridation, t =9.506, P ＜ 0.01);the prevalence of dental caries was increased from 52.73％ (29/55, before defluoridation) to 63.24％ (43/68, after defluoridation), however, the difference was not significant (x2 =1.383, P ＞ 0.05).The DMFT increased from 1.18 (before defluoridation) to 1.68 (after defluoridation), and the epidemic levels of dental caries were all at lower levels.The relationship between urine fluoride level and the prevalence of dental caries as well as the DMFT before defluoridation was a U-shape dose-response curve;which was gone after defluoridation.Conclusions The urinary fluoride level is significantly decreased after defluoridation for 10 years, the prevalence of dental caries is increased but not significantly.The results of this study indicate that the measure of fluoridation to prevent dental caries needs to be further validated.

Objective:To evaluate the incidence and case fatality rate of cardiovascular disease (CVD) among populations in urban and rural communities in eastern, central and western regions of China.Methods:The present study was based on the data of the Prospective Urban and Rural Epidemiology (PURE)-China cohort, which enrolled participants who had at least one follow-up visit and complete information on age and sex. Information on baseline demographics, cardiovascular risk factors, and prevention and treatment for CVD were collected. CVD and mortality events were documented using the standardized case report form of the PURE Global Study to assess the incidence and case fatality rate of CVD among populations in urban and rural communities in eastern, central and western China.Results:This study included a total of 47 262 community-dwelling participants (age: (51.1±9.6) years; female, n=27 529, 58.2%) from 115 urban and rural communities in 12 provinces across the eastern, central, and western regions of China. Over a follow-up period of 11.9 (9.5, 12.6) years, 2 686 deaths and 5 873 cardiovascular events were documented. The incidence of CVD was 11.90 (95%CI: 11.60-12.21)/1 000 person-years. A significant difference in CVD incidence was observed across regions ( Ptrend<0.001), which was highest in the western provinces (13.99 (95% CI: 13.33-14.65)/1 000 person-years), intermediate in the eastern provinces (11.92 (95% CI: 11.52-12.33)/1 000 person-years), and lowest in the central provinces (8.87 (95% CI: 8.25-9.50)/1 000 person-years). The 1-year case fatality rate of CVD demonstrated an increasing trend from eastern to western regions (eastern: 10.20% (95% CI: 6.95-14.73); central: 13.50% (95% CI: 9.90-18.14); western: 18.62% (95% CI: 14.95-22.94); Ptrend<0.001). Moreover, the incidence of major CVD was consistently higher in rural areas compared with urban areas across eastern ( P<0.001), central ( P=0.01) and western ( P<0.001)_regions, respectively. The 1-year case fatality rate in rural areas was also significantly higher compared with that in urban areas in both eastern ( P<0.001) and western regions ( P=0.02). Conclusions:The incidence and case fatality rate of CVD were high among middle-aged population in China, especially those in western regions with low socioeconomic levels and in rural areas.