Still, we included all available information about goiter and TNs from the past three decades and this report is the first to document the epidemiological status of both diseases before and after the USI program in mainland China. In addition, our work underscores the need for additional population-based studies in areas excluded from this analysis. Our data show that the implementation of USI program is beneficial but may pose iodine risks; therefore, salt iodization standards should be set according to local conditions. Also, some epidemiology studies remain to be undertaken, and these are essential for comprehensive original data on the epidemiology and distribution of thyroid diseases. Our future work will include a national baseline study on thyroid diseases which will be implemented from 2014 to 2016 and these data will provide broad and accurate information for other researchers. Because high cure rates can be expected for early stages of gastric cancer, and non-randomized evidence suggests that radiographic screening can decrease gastric-cancer-specific mortality, several Asian countries have initiated cancer-screening programs using upper gastrointestinal tract GS-5734 photofluorography or gastric endoscopy. However, recent nationwide gastric cancer screening rates for the general population in Japan have been unsatisfactorily low ; therefore, a major current focus is on developing a risk-stratified screening program by efficiently identifying high-risk populations. However, these studies have small sample sizes and use heterogeneous designs, making it difficult to interpret the published data. Also, those studies that have assessed the prediction model typically focus on relative risk estimates and fail to assess the performance of the model. We also aimed to quantitatively explore the calibration and discrimination of the prediction model based on the reported data. We took particular care to identify publications with at least partially overlapping populations by comparing authors, centers, recruitment periods, and patient demographic characteristics. In the case of multiple publications from one study, we included only the publication with the longest follow-up. We abstracted information on aspects of the design and conduct of individual studies using a checklist specifically designed for assessing studies of prognostic tests. Items included study design, selection of study participants, description of tested population, inclusion and exclusion criteria, start point of followup, description of test characteristics, description of ascertainment of gastric cancer development, follow-up period, and methods of data analysis.