School of Public Health, University of California, Berkeley, CA, United States.
ResMed, San Diego, CA, United States.
Front Public Health. 2024 Oct 9;12:1417450. doi: 10.3389/fpubh.2024.1417450. eCollection 2024.
Air pollution is widely acknowledged as a significant factor in respiratory outcomes, including coughing, wheezing, emergency department (ED) visits, and even death. Although several literature reviews have confirmed the association between air pollution and respiratory outcomes, they often did not standardize associations across different studies and overlooked other increasingly impactful pollutants such as trace metals. Recognizing the importance of consistent comparison and emissions of non-exhaust particles from road traffic, this study aims to comprehensively evaluate the standardized effects of various criteria pollutants and trace metals on respiratory health.
We conducted a comprehensive meta-analysis of peer-reviewed journal articles on air pollution and respiratory outcomes published between 1 January 2000, and 1 June 2024. The study included children (age < 18 years), adults (age ≥ 18 years), and all age groups exposed to criteria pollutants established by the US Environmental Protection Agency National Ambient Air Quality Standards and over 10 trace metals. Using databases, such as PubMed, MEDLINE, Web of Science Core Collection, and Google Scholar, we identified 579 relevant articles. After rigorous screening and quality assessment using the Newcastle-Ottawa Scale, 50 high-quality studies were included. We converted various reported outcomes (e.g., odds ratios, relative risk, and percent increase) to a standardized odds ratio (OR) for comparability and performed meta-analyses using R 4.4.0 and related packages, ensuring the robustness of our findings.
Our meta-analysis indicated significant associations between air pollutants and respiratory outcomes. For particulate matter with diameter ≤ 2.5 μm (PM), the overall ORs for children, adults, and combined age groups were 1.31, 1.10, and 1.26, respectively, indicating a consistent positive association. Similar positive associations were observed for particulate matter with diameter ≤ 10 μm (PM) and other pollutants, with children showing higher susceptibility than adults. The analysis of trace metals also showed significant associations; however, these findings require cautious interpretation due to the small number of studies.
Our study supports associations between air pollutants, including non-exhaust trace metals, and respiratory outcomes across different age groups. The findings underscore the need for stringent environmental health policies and further research, especially in regions with higher pollution levels. The future studies should consider long-term and short-term exposures separately and include diverse populations to improve the accuracy and generalizability of the results.
空气污染被广泛认为是呼吸系统疾病的重要因素，包括咳嗽、喘息、急诊就诊，甚至死亡。尽管有几项文献综述已经证实了空气污染与呼吸系统疾病之间的关联，但它们往往没有对不同研究中的关联进行标准化，也忽略了其他越来越有影响的污染物，如痕量金属。鉴于一致比较和道路交通非排放颗粒排放的重要性，本研究旨在全面评估各种标准污染物和痕量金属对呼吸健康的标准化影响。
我们对 2000 年 1 月 1 日至 2024 年 6 月 1 日期间发表的有关空气污染与呼吸系统疾病的同行评议期刊文章进行了全面的荟萃分析。该研究包括儿童（年龄 < 18 岁）、成人（年龄 ≥ 18 岁）和所有年龄段的人群，他们接触的是美国环境保护署国家环境空气质量标准规定的标准污染物，以及超过 10 种痕量金属。我们使用数据库，如 PubMed、MEDLINE、Web of Science Core Collection 和 Google Scholar，识别了 579 篇相关文章。然后，我们使用纽卡斯尔-渥太华量表进行了严格的筛选和质量评估，最终纳入了 50 项高质量的研究。我们将各种报告的结果（例如，比值比、相对风险和百分比增加）转换为标准化比值比（OR）以进行可比性，并使用 R 4.4.0 和相关软件包进行了荟萃分析，以确保我们的发现具有稳健性。
我们的荟萃分析表明，空气污染物与呼吸系统疾病之间存在显著关联。对于直径≤2.5μm 的颗粒物（PM），儿童、成人和混合年龄组的总体 OR 分别为 1.31、1.10 和 1.26，表明存在一致的正相关关系。对于直径≤10μm 的颗粒物（PM）和其他污染物也观察到了类似的正相关关系，儿童的敏感性高于成人。痕量金属的分析也显示出显著的关联；然而，由于研究数量较少，这些发现需要谨慎解释。
我们的研究支持包括非排放痕量金属在内的空气污染物与不同年龄组的呼吸系统疾病之间的关联。这些发现强调了需要制定严格的环境健康政策和进行进一步的研究，特别是在污染水平较高的地区。未来的研究应分别考虑长期和短期暴露，并纳入更多样化的人群，以提高结果的准确性和普遍性。
