Study on PM2.5 pollution and the mortality due to lung cancer in China based on geographic weighted regression model.

BACKGROUND: PM2.5 has become a major component of air pollution in China and has led to a series of health problems. The mortality rate caused by lung cancer has reached the point where it cannot be ignored in China. Air pollution is becoming more and more serious in China, which is increasingly affecting people's lives and health. METHODS: Considering the variations in the geographical environment in China, this paper studied the relationship between PM2.5 concentration and lung cancer mortality based on the geographical weighted regression model in 31 provinces in 2004 and 2008, autonomous regions and municipalities of China. RESULTS: The results indicated there was a significant positive correlation between PM2.5 concentration and lung cancer mortality (r = 0.0052, P = 0.036). Additionally, the longer the time of exposure to PM2.5 is, the higher morbidity is. CONCLUSION: It is suggested that the Chinese government should launch some environmental policy, especially in those areas with severe PM2.5 pollutions, and keep the citizens away from exposure to PM2.5 pollution in the long term.

A reverse factual analysis of the association between smoking and memory decline in China.

BACKGROUND: Whether smoking accelerates memory recession has been a topic of significant research. However, randomised controlled trials are not easy to carry out, and does not comply with the ethics of research. And observation method which based on the most readily observed data is easy to draw the wrong conclusions without adjustment. The memory difference between smokers and non-smokers may not really represent the real differences between their memories. METHODS: In response to these limitations, we adopt propensity score method to match the samples and solve the estimated selection bias and confounding bias on elderlies aged 60 years and over based on Chinese Longitudinal Healthy Longevity Survey (2011) data. The respondents are divided into non-smokers, people who used to smoke but not now, and people who used to smoke and still now. To balance the similarity between different groups on their propensity score weighted distributions of pretreatment covariates, we use generalized boosted models to estimate the multiply treatment propensity scores. RESULTS: The results show that compared with non-smokers, people who used to smoke and still now respectively have a decrease 0.0283, 0.0735, 0.0091 on self-evaluation memory, daily living activities, and cognitive function. People who used to smoke but not now have a decrease 0.0224 on daily living activities, while have an increase 0.0054 and 0.0104 on self-evaluation memory, and cognitive function. CONCLUSION: The PSM has considerable utility to control pre-treatment imbalances on observed covariates in non-randomised or observational data.

How the Establishment of the National Civilized City Promotes Urban Green Development: From the Perspective of Administrative Competing Theory-A Quasi Experiment Study in China.

Green development is the core goal for contemporary urban areas. It has become essential to explore new types of urban green development, and the concept of the "national civilized city" which is the most influential city brand in China, has emerged. Drawing upon the administrative competing theory, based on the panel data of 281 cities in China from 2000 to 2018, this paper employs a propensity scores matching (PSM) design and a difference-in-difference (DID) approach to examine the influence of the establishment of the national civilized city policy on the green development of prefecture-level cities in China. First, the result shows that the establishment of the national civilized city policy can significantly improve the urban green total factor productivity (GTFP). Second, the mediation mechanism analyses show that the establishment of national civilized city policy can promote cities to increase their investment in R&D, increase the financial investment in environmental governance, and optimize the industrial structure, which further lays a solid foundation for urban green development. Third, the heterogeneity analysis shows that the impact of civilized city construction on urban GTFP is different in terms of population and economic scales. The results show that the weight of environmental management and R&D investment should be increased in the evaluation index of the national civilized city, and the promotion of urban green development should be maximized.

Depression among left-behind children in China.

By retrieving literature published from 2005 to 2015 from Chinese National Knowledge Infrastructure, Wanfang, Vip, PubMed, and Web of Science, we filtered out studies using the Children's Depression Inventory only and compared left-behind children and non-left-behind children. The methodological quality of the papers was evaluated using the Newcastle-Ottawa Scale. Finally, we included six studies to carry out a meta-analysis. The results showed that the Children's Depression Inventory scores of left-behind children are significantly higher than those of non-left-behind children (standardized mean difference: -0.233, 95% confidence interval: -0.036 to -0.430, p < 0.05).