Background: It is well known that air pollution causes respiratory morbidity and mortality by inducing airway inflammation. However, whether long-term exposure to air pollution is associated with increased incidence of chronic obstructive pulmonary disease (COPD) is controversial. Methods: We conducted a systematic review and meta-analysis with a random-effects model to calculate the pooled risk estimates of COPD development per 10 μg/m³ increase in individual air pollutants. PubMed, Embase, and Cochrane Library were searched from the date of their inception to August 2019 to identify long-term (at least three years of observation) prospective longitudinal studies that reported the risk of COPD development due to exposure to air pollutants. The air pollutants studied included particulate matter (PM_2.5 and PM₁₀) and nitrogen dioxide (NO₂). Results: Of the 436 studies identified, seven met our eligibility criteria. Among the seven studies, six, three, and five had data on PM_2.5, PM₁₀, and NO₂, respectively. The meta-analysis results showed that a 10 μg/m³ increase in PM_2.5 is associated with increased incidence of COPD (pooled HR 1.18, 95% CI 1.13–1.23). We also noted that a 10 μg/m³ increase in NO₂ is marginally associated with increased incidence of COPD (pooled HR 1.07, 95% CI 1.00–1.16). PM₁₀ seems to have no significant impact on the incidence of COPD (pooled HR 0.95, 95% CI 0.83–1.08), although the number of studies was too small. Meta-regression analysis found no significant effect modifiers. Conclusions: Long-term exposure to PM_2.5 and NO₂ can be associated with increased incidence of COPD.

背景：众所周知，空气污染会引起呼吸道炎症，从而导致呼吸道疾病和死亡。然而，长期暴露于空气污染是否与慢性阻塞性肺疾病（COPD）的发生率增加有关。方法：我们使用随机效应模型进行了系统的回顾和荟萃分析，以计算每10μg/ m ³的COPD发生风险汇总个别空气污染物的增加。从成立日期到2019年8月，对PubMed，Embase和Cochrane库进行了检索，以鉴定长期（至少观察三年）的前瞻性纵向研究，该研究报告了由于暴露于空气污染物而导致COPD形成的风险。研究的空气污染物包括颗粒物（PM _2.5和PM ₁₀）和二氧化氮（NO ₂）。结果：在确定的436项研究中，有7项符合我们的资格标准。在这7项研究中，分别有6项，3项和5项具有PM _2.5，PM ₁₀和NO _2的数据。荟萃分析结果显示10μg/ m ³PM _2.5增加与COPD发生率增加相关（合并HR 1.18，95％CI 1.13-1.23）。我们还注意到，NO ₂增加10μg/ m ³与COPD的发生率增加相关（合并HR 1.07，95％CI 1.00-1.16）。尽管研究数量太少，但PM ₁₀似乎对COPD的发生率没有显着影响（合并HR 0.95，95％CI 0.83–1.08）。荟萃回归分析未发现明显的效应修饰因子。结论：长期暴露于PM _2.5和NO ₂可能与COPD发生率增加有关。