ASSESSING THE ACUTE AND CHRONIC CARDIO-RESPIRATORY HEALTH IMPACTS OF AMBIENT AIR POLLUTION IN CHINA

环境空气污染（AAP）的急性和慢性健康影响现在在流行病学文献中得到一致的记录。然而，目前大多数证据适用于发达地区，在这些地区，健康结果数据和污染物数据更容易获得，质量保证程度更高。因此，从发达地区向包括中国在内的低收入和/或中等收入国家（LMIC's）的健康影响的一般外推在证据基础中越来越普遍。这种结果的外推通常是更好的选择，因为对低收入和中等收入国家本身的研究经常受到方法问题的限制。这些问题源于其复杂的医疗保健系统、缺乏统一的健康数据记录以及一贯的暴露错误分类。因此，关于AAP暴露对低收入和中等收入国家人口的健康影响的证据仍然是轶事。特别是在中国，经济的蓬勃发展是以牺牲空气质量为代价的，AAP每年造成约160万人死亡(1)。然而，即使在中国，就接触AAP对人口健康的确切影响而言，仍然存在很大的不确定性。此外，尽管AAP暴露无处不在，但大多数高质量的流行病学研究都是在中国的“特大城市”内进行的，很少考虑到更广泛地区的健康影响。因此，本项目旨在准确确定AAP暴露对中国不同地区的急性和慢性健康影响，使用以前几乎专门为发达地区保留的方法。方法本项目将利用中国嘉道里生物库（CKB），这是一个覆盖中国10个不同地区的50万参与者的队列。通过健康保险数据链接提供高质量的标准化健康数据，将使CKB内个人的健康结果能够准确地与AAP暴露有关。本文将从中国五个城市地区的心血管和呼吸系统住院病例的角度来研究AAP暴露对急性健康的影响。这将涉及从中国国家空气污染监测网络获得的主要空气污染物（PM2.5, PM10, SO2, NOx, O3）的单一污染物模型。将进行时间序列分析（使用预先指定的滞后时间），并生成广义的加性模型，以便准确确定AAP暴露与CKB参与者的急性心血管/呼吸事件之间的关系。与大多数研究只关注固定监测点的单一污染物模型不同，该项目将利用多污染物模型进行敏感性分析。除了主要的混杂因素包括人口特征、季节趋势和气象变量外，它还将检查各种潜在的影响调节因素，如不同的地理区域。就接触AAP的慢性健康影响而言，这将包括检查；慢性肾病参与者长期AAP暴露与血压/高血压的关系。慢性肾病参与者长期AAP暴露与心血管/呼吸系统疾病发病率的关系为了量化CKB参与者对AAP的长期暴露，将利用卫星对PM2.5的估计，并进一步校准固定监测测量和个人暴露评估。这些暴露评估方法将最大限度地减少暴露错误分类，为中国AAP暴露对健康的影响提供更可靠的估计。参考文献(1)卫生计量与评价研究所。恶劣的空气质量每年导致550万人死亡。2016年;可在：http://www.healthdata.org/news-release/poor-air-quality-kills-55-million-worldwide-annually。2016年10月24日发布。

BackgroundBoth the acute and chronic health impacts of ambient air pollution (AAP) are now consistently documented throughout epidemiological literature. However, the majority of evidence currently applies to developed regions where both health outcome data and pollutant data are more readily obtainable with greater degree of quality assurance. Thus, generic extrapolation of the health impacts from developed regions into low and/or middle income countries (LMIC's) including China is increasingly common within the evidence base. Such extrapolation of results often presents as the better option, with research in LMIC's themselves frequently restricted by methodological issues. These issues stem from their complex healthcare systems, lack of unified health data recording, and consistent exposure misclassification. Therefore, evidence on the health impacts of AAP exposure for populations within LMIC's exclusively remains anecdotal. Within China specifically, economic development has flourished at the inherent sacrifice of air quality, with AAP causing an estimated 1.6 million deaths annually (1). However, even within China there remains significant uncertainty in terms of the exact health impacts of AAP exposure on the population. Furthermore, the majority of high quality epidemiological studies are performed within the Chinese "mega-cities" with little consideration for the health effects in wider regions, despite the ubiquity of AAP exposure. This project therefore aims to accurately determine the acute and chronic health effects of AAP exposure within varying regions of China, using a methodology previously reserved almost exclusively for developed regions.MethodsThis project will utilise China Kadoorie Biobank (CKB), a cohort of 0.5 million participants covering 10 diverse regions of China. The availability of high quality standardised health data through health insurance data linkage will enable health outcomes to be accurately examined in relation to AAP exposure for individuals within the CKB. The acute health effects of AAP exposure will be examined in terms of both cardiovascular and respiratory hospital admissions, documented from five urban areas in China. This will involve single pollutant modelling for the primary air pollutants (PM2.5, PM10, SO2, NOx, O3) obtained from the Chinese National Air pollution monitoring network. Time-series analysis (using pre-specified lags) will be performed, and generalised additive models generated in order to accurately determine the association between AAP exposure and acute cardiovascular/respiratory events for CKB participants. Unlike the majority of studies which focus solely on single pollutant modelling from fixed monitoring sites, this project will perform sensitivity analysis utilising multi-pollutant modelling. It will also examine various potential effect modifiers such as differing geographic region, in addition to the main confounders including demographic characteristics, seasonal trends, and meteorological variables. In terms of the chronic health impacts of AAP exposure, this will involve examining;- The association of long term AAP exposure and blood pressure/hypertension in CKB participants. - The association of long term AAP exposure and incidence of cardiovascular/respiratory disease in CKB participants. To quantify long term exposure to AAP for CKB participants, satellite based estimates of PM2.5 will be utilised with further calibration from fixed monitoring measurements and personal exposure assessment. These methods of exposure assessment will minimise exposure misclassification providing a more reliable estimate of the health impacts of AAP exposure in China. Bibliography(1) Institute for Health Metrics and Evaluation. Poor air quality kills 5.5 million annually. 2016; Available at: http://www.healthdata.org/news-release/poor-air-quality-kills-55-million-worldwide-annually. Accessed 24/10, 2016.