Weeberb J. Requia and Moataz Mahmoud are with McMaster University, McMaster Institute for Transportation and Logistics, Hamilton, Ontario, Canada. Matthew D. Adams is with Ryerson University, Department of Geography and Environmental Studies, Toronto, Ontario. Altaf Arain is with McMaster University, School of Geography and Earth Sciences, Hamilton. Stefania Papatheodorou is with Cyprus University of Technology, Cyprus International Institute for Environmental and Public Health, Limassol, Cyprus. Petros Koutrakis is with Harvard University, Harvard T. H. Chan School of Public Health, Boston, MA.
Am J Public Health. 2018 Apr;108(S2):S123-S130. doi: 10.2105/AJPH.2017.303839. Epub 2017 Oct 26.
Little is known about the health risks of air pollution and cardiorespiratory diseases, globally, across regions and populations, which may differ because of external factors.
We systematically reviewed the evidence on the association between air pollution and cardiorespiratory diseases (hospital admissions and mortality), including variability by energy, transportation, socioeconomic status, and air quality.
We conducted a literature search (PubMed and Web of Science) for studies published between 2006 and May 11, 2016.
We included studies if they met all of the following criteria: (1) considered at least 1 of these air pollutants: carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, or particulate matter (PM or PM); (2) reported risk for hospital admissions, mortality, or both; (3) presented individual results for respiratory diseases, cardiovascular diseases, or both; (4) considered the age groups younger than 5 years, older than 65 years, or all ages; and (5) did not segregate the analysis by gender.
We extracted data from each study, including location, health outcome, and risk estimates. We performed a meta-analysis to estimate the overall effect and to account for both within- and between-study heterogeneity. Then, we applied a model selection (least absolute shrinkage and selection operator) to assess the modifier variables, and, lastly, we performed meta-regression analyses to evaluate the modifier variables contributing to heterogeneity among studies.
We assessed 2183 studies, of which we selected 529 for in-depth review, and 70 articles fulfilled our study inclusion criteria. The 70 studies selected for meta-analysis encompass more than 30 million events across 28 countries. We found positive associations between cardiorespiratory diseases and different air pollutants. For example, when we considered only the association between PM and respiratory diseases ( Figure 1 , we observed a risk equal to 2.7% (95% confidence interval = 0.9%, 7.7%). Our results showed statistical significance in the test of moderators for all pollutants, suggesting that the modifier variables influence the average cardiorespiratory disease risk and may explain the varying effects of air pollution.
Variables related to aspects of energy, transportation, and socioeconomic status may explain the varying effect size of the association between air pollution and cardiorespiratory diseases. Public Health Implications. Our study provides a transferable model to estimate the health effects of air pollutants to support the creation of environmental health public policies for national and international intervention.
全球范围内，人们对空气污染与心肺疾病之间的健康风险知之甚少，且因外部因素的影响，不同地区和人群之间可能存在差异。
我们系统地回顾了有关空气污染与心肺疾病（住院和死亡率）之间关联的证据，包括因能源、交通、社会经济地位和空气质量不同而产生的可变性。
我们对 2006 年至 2016 年 5 月 11 日期间发表的文献进行了文献检索（PubMed 和 Web of Science）。
如果研究符合以下所有标准，则将其纳入：（1）考虑了以下至少 1 种空气污染物：一氧化碳、二氧化硫、二氧化氮、臭氧或颗粒物（PM 或 PM）；（2）报告了住院、死亡率或两者的风险；（3）呈现了呼吸疾病、心血管疾病或两者的个体结果；（4）考虑了 5 岁以下、65 岁以上或所有年龄组；（5）未按性别对分析进行细分。
我们从每项研究中提取数据，包括地点、健康结果和风险估计。我们进行了荟萃分析，以估计总体效应并考虑到研究内和研究间的异质性。然后，我们应用模型选择（最小绝对收缩和选择算子）来评估修饰变量，最后，我们进行了荟萃回归分析，以评估导致研究间异质性的修饰变量。
我们评估了 2183 项研究，其中选择了 529 项进行深入审查，有 70 篇文章符合我们的研究纳入标准。这 70 项研究纳入荟萃分析的结果涵盖了 28 个国家的 3000 多万例事件。我们发现心肺疾病与不同空气污染物之间存在正相关关系。例如，当我们仅考虑 PM 与呼吸疾病之间的关联时（图 1），我们发现风险等于 2.7%（95%置信区间=0.9%，7.7%）。我们的结果表明，所有污染物的修饰变量检验均具有统计学意义，这表明修饰变量会影响心肺疾病的平均风险，并可能解释空气污染的不同影响。
与能源、交通和社会经济地位方面相关的变量可能解释了空气污染与心肺疾病之间关联的效应大小差异。公共卫生意义。我们的研究提供了一种可转移的模型来估计空气污染物对健康的影响，以支持为国家和国际干预制定环境健康公共政策。
