Objective: To analyze the second hand smoke exposure and related factors of nonsmoking junior middle school students in Beijing, so as to provide a data support for formulating tobacco control measures. Methods: The multistage cluster random sampling method was used to select junior middle school students in Beijing. The valid data of 4 494, 4 915 and 3 792 nonsmoking middle school students were obtained from three waves of youth tobacco epidemic surveillance in 2013 (September to October), 2019 (August to November) and 2021 (September to December) wave, respectively. The information was collected by the national youth tobacco epidemic surveillance questionnaire. The complex sampling data analysis module of SPSS 21.0 was used to descriptive analysis and multivariate Logistic regression. Results: The proportions of secondhand smoke exposure of nonsmoking junior middle school students in the four types of places in the past 7 days in 2013, 2019 and 2021 in Beijing were 76.4%, 71.4% and 65.7%, respectively, with statistically significant differences (χ2=126.10, P<0.01). The proportions of that found someone smoking in the campus in the three waves of survey were 34.7%, 27.9% and 21.1% (χ2=209.78), the proportion of that found teachers smoking daily were 2.7%, 1.8% and 1.3% (χ2=22.14) (P<0.01), respectively. Multivariate Logistic regression analysis showed both parents smoking (OR=8.47, 95%CI=4.36-16.48), father smoking (OR=3.51, 95%CI=2.75-4.49), and friends smoking (OR=1.88, 95%CI=1.39-2.55) were the influencing factors of secondhand smoke exposure in four types of places of nonsmoking junior middle school students in 2013. Both parents smoking (OR=2.37, 95%CI=1.33-4.22), father smoking (OR=2.80, 95%CI=2.33-3.37), friends smoking (OR=2.24, 95%CI=1.71-2.92), and teaching the tobacco hazards in class (OR=0.77, 95%CI=0.64-0.93) were the influencing factors of secondhand smoke exposure in four types of places for nonsmoking middle school students in 2019. Both parents smoking (OR=3.93, 95%CI=2.29-6.75), fathers smoking (OR=3.30, 95%CI=2.72-3.99), and teaching the tobacco hazards in the class (OR=0.81, 95%CI=0.68-0.97) were the influential factor of secondhand smoke exposure in four types of places of nonsmoking junior middle school students in 2021 (P<0.05). Conclusions The secondhand smoke exposure of nonsmoking middle school students in Beijing has improved, but still is a high level. It is necessary to take corresponding measures to effectively protect nonsmoking junior middle school students from the harm of secondhand smoke.

Under the limitation of cross-sectional studies, more researchers are turning their attention to maternal and child cohort studies. However, some problems do exist in the traditional maternal and child cohort studies, if data is only gathered from the hospitals. The limitation would include the contents of research and the high rate of loss to follow-up. With the integration of different medical traits and the progress in big data, the development of maternal and child related cohorts, with characteristics of dynamic follow-up and data sharing, through combining the information and health service systems of different institutions, seem in urgent need. This paper aims to provide some basic achievements in conducting maternal and child cohorts that can serve the related health problems through full-life cycle, and provide new references on conducting cohort studies, aiming at special population or diseases.

Objective:To understand the research progress and quality of lung cancer screening guidelines and consensus in China and abroad, and to provide reference for the formulation of high-quality lung cancer screening guidelines in China.Methods:Databases including PubMed, Medline, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, SinoMed, VIP and Wanfang Data were searched, websites and important references were also searched by hand retrieval. The Appraisal of Guidelines for Research & Evaluation Ⅱ(AGREE Ⅱ) and Reporting Items for Practice Guidelines in Healthcare (RIGHT) were used to assess the quality of newly published or updated guidelines and consensus.Results:A total of 9 guidelines and consensus published between 2015 and 2020 were included in this study, with countries including the United States, China, Canada, Saudi Arabia and South Africa. The field of scope and purpose and clarity of presentation scored relatively high but the rigor of development and applicability scored low. Five guidelines were judged to be A-level, all of which were published abroad, and the remaining four were B-level, including three guidelines and consensus issued by China and 1 guideline issued by South Africa. The report rate of RIGHT were higher in basic information and background, lower in review and quality assurance, funding and declaration and management of interests. There were 5 guidelines with a good level and 4 guidelines and consensus with a moderate level. The best overall quality guidelines were those published by the American College of Chest Physicians in 2018 and by the Canadian Task Force on Preventive Health Care in 2016.Conclusions:The number of countries and institutions that issue lung cancer screening guidelines and consensus had been increasing gradually, but the quality in China remained low. It is necessary to develop high-quality lung cancer screening guidelines suitable for China's national conditions in combination with evidence-based methods to guide practice.

Data standard plays an important role in the process of data collection, Integration and sharing in clinical cohort studies, and more attention have been paid to it. This paper summarizes the 5 international proven data standard model, analyze their characteristics and development status, and match their data modules with the general data set of the clinical cohorts to evaluate the international data standard models' applicability and provide reference for the development and improvement of the data standard model for clinical cohort studies in China.