A Natural Experiment in Cheongju

학위논문(석사)--서울대학교 대학원 :보건대학원 보건학과,2019. 8. 황승식.Objectives: The community water fluoridation (referred to as CWF) was conducted in Cheongju City in South Korea from 1982 to 2004. The purpose of this study was to evaluate epidemiologically the risk of CWF for adverse health effect, specifically bone related diseases (hip fracture, osteoporosis, and bone cancer). Design: This study was an ecological study based on natural experiment design. Methods: Study participants were residents in Cheongju from 2004 to 2013 and data were collected by National Health Insurance Service database. Hip fracture, osteoporosis, and bone cancer among adverse health diseases were selected. We ensured the trend of medical use trend after CWF ceased in Cheongju and analyzed the prevalence of selected disease to evaluate the risk of CWF. The Hierarchical Bayesian spatio-temporal Poisson regression model which consider spatial and temporal correlation was performed to analyze the association between implementation of CWF and the prevalence of selected diseases of residents in Cheongju. Conditional autocorrelation (CAR) which is frequently used to control spatial correlation was applied in this analysis. The calculation method for Bayesian estimation was based on the R-INLA. Results: After CWF ceased in Cheongju, we observed increasing trend in hip fracture, osteoporosis and bone cancer in both areas (fluoridated and non-fluoridated areas). However, there was no statically significant difference in the prevalence of selected bone diseases in CWF area (RR = 0.95, 95% CrI: 0.87-1.05; RR = 0.94, 95% CrI: 0.87-1.02; RR = 1.20 95% CrI: 0.89-1.61, respectively). Conclusions: We used a spatiotemporal method to analyze the medical use of selected bone diseases from 2004 to 2013 in Cheongju with small area unit by using National Health Insurance Service data. Our study verified that there was no statistically different in prevalence of selected bone disease between CWF and non-CWF areas after CWF was ceased. With this results, we confirmed that fluoridation has no negative impacts on adverse health effects. There was no clear evidence that exposure of CWF increased the risk on health effects. Our study provided one of the scientific evidence and it is necessary to research and develop as a public health prevention program continuously.Abstract i CHAPTER 1. INTRODUCTION 1 1.1 Background 1 1.2 Literature review 6 1.3 Study objective 15 CHAPTER 2. METHODS 16 2.1 Study design, and setting 16 2.2 Data descriptions and study subjects 19 2.3 Variables 20 2.4 Statistical analysis 23 CHAPTER 3. RESULTS 33 3.1 General characteristics of study population 33 3.2 Comparison of crude and age-standardized rates 36 3.3 Comparison of the relative risk of selected diseases 39 3.4 Disease mapping of selected diseases 42 3.5 Comparison of the performance of the models 45 CHAPTER 4. DISCUSSION 48 4.1 Summary of results: A new finding of this study 48 4.2 Comparison with previous studies 48 4.3 Strengths and Limitations of this study 49 4.4 Public health implications 51 CHAPTER 5. CONCLUSION 52 BIBLIOGRAPHY 53 APPENDIX A: Summary of systematic review results 59 APPENDIX B: R-INLA coding 66 APPENDIX C: CARBayesST coding 67 APPENDIX D: Compare the relative risk 68 APPENDIX E: Disease mapping with three different regions 69 APPENDIX F: Outline of the methods 71 APPENDIX G: RECORD statement 72 Abstract (Korean) 79Maste

Indacenodibenzothiophenes: Synthesis, Optoelectronic Properties and Materials Applications of Molecules with Strong Antiaromatic Character

Indeno[1,2-b]fluorenes (IFs), while containing 4n π-electrons, are best described as two aromatic benzene rings fused to a weakly paratropic s-indacene core. In this study, we find that replacement of the outer benzene rings of an IF with benzothiophenes allows the antiaromaticity of the central s-indacene to strongly reassert itself. Herein we report a combined synthetic, computational, structural, and materials study of anti- and syn-indacenodibenzothiophenes (IDBTs). We have developed an efficient and scalable synthesis for preparation of a series of aryl- and ethynyl-substituted IDBTs. NICS-XY scans and ACID calculations reveal an increasingly antiaromatic core from [1,2-b]IF to anti-IDBT, with syn-IDBT being nearly as antiaromatic as the parent s-indacene. As an initial evaluation, the intermolecular electronic couplings and electronic band structure of a diethynyl anti-IDBT derivative reveal the potential for hole and/or electron transport. OFETs constructed using this molecule show the highest hole mobilities yet achieved for a fully conjugated IF derivative

The Association between Community Water Fluoridation and Bone Diseases: A Natural Experiment in Cheongju, Korea

The present study aimed to investigate the association between bone diseases and community water fluoridation (CWF). An ecological study with a natural experiment design was conducted in Cheongju, South Korea, from 1 January 2004 to 31 December 2013. The community water fluoridation program was implemented in Cheongju and divided into CWF and non-CWF areas. To observe adverse health effects related to bone diseases, we conducted a spatio-temporal analysis of the prevalence of hip fracture, osteoporosis, and bone cancer in residents who have lived in CWF and non-CWF areas using National Health Insurance Service data. First, we used standardized incidence ratios to estimate the disease risk. Second, the hierarchical Bayesian Poisson spatio-temporal regression model was used to investigate the association between the selected bone diseases and CWF considering space and time interaction. The method for Bayesian estimation was based on the R-integrated nested Laplace approximation (INLA). Comparing the CWF area with the non-CWF area, there was no clear evidence that exposure to CWF increased health risks at the town level in Cheongju since CWF was terminated after 2004. The posterior relative risks (RR) of hip fracture was 0.95 (95% confidence intervals 0.87, 1.05) and osteoporosis was 0.94 (0.87, 1.02). The RR in bone cancer was a little high because the sample size very small compared to the other bone diseases (RR = 1.20 (0.89, 1.61)). The relative risk of selected bone diseases (hip fractures, osteoporosis, and bone cancer) increased over time but did not increase in the CWF area compared to non-CWF areas. CWF has been used to reduce dental caries in all population groups and is known for its cost-effectiveness. These findings suggest that CWF is not associated with adverse health risks related to bone diseases. This study provides scientific evidence based on a natural experiment design. It is necessary to continue research on the well-designed epidemiological studies and develop public health prevention programs to help in make suitable polices