BACKGROUND Air pollution is both a sensory blight and a threat to human health. Inhaled environmental pollutants can be naturally occurring or human-made, and include traffic-related air pollution (TRAP), ozone, particulate matter (PM) and volatile organic compounds, among other substances, including those from secondhand smoking. Studies of air pollution on reproductive and endocrine systems have reported associations of TRAP, secondhand smoke (SHS), organic solvents and biomass fueled-cooking with adverse birth outcomes. While some evidence suggests that air pollution contributes to infertility, the extant literature is mixed, and varying effects of pollutants have been reported. OBJECTIVE AND RATIONALE Although some reviews have studied the association between common outdoor air pollutants and time to pregnancy (TTP), there are no comprehensive reviews that also include exposure to indoor inhaled pollutants, such as airborne occupational toxicants and SHS. The current systematic review summarizes the strength of evidence for associations of outdoor air pollution, SHS and indoor inhaled air pollution with couple fecundability and identifies gaps and limitations in the literature to inform policy decisions and future research. SEARCH METHODS We performed an electronic search of six databases for original research articles in English published since 1990 on TTP or fecundability and a number of chemicals in the context of air pollution, inhalation and aerosolization. Standardized forms for screening, data extraction and study quality were developed using DistillerSR software and completed in duplicate. We used the Newcastle-Ottawa Scale to assess risk of bias and devised additional quality metrics based on specific methodological features of both air pollution and fecundability studies. OUTCOMES The search returned 5200 articles, 4994 of which were excluded at the level of title and abstract screening. After full-text screening, 35 papers remained for data extraction and synthesis. An additional 3 papers were identified independently that fit criteria, and 5 papers involving multiple routes of exposure were removed, yielding 33 articles from 28 studies for analysis. There were 8 papers that examined outdoor air quality, while 6 papers examined SHS exposure and 19 papers examined indoor air quality. The results indicated an association between outdoor air pollution and reduced fecundability, including TRAP and specifically nitrogen oxides and PM with a diameter of ≤2.5 µm, as well as exposure to SHS and formaldehyde. However, exposure windows differed greatly between studies as did the method of exposure assessment. There was little evidence that exposure to volatile solvents is associated with reduced fecundability. WIDER IMPLICATIONS The evidence suggests that exposure to outdoor air pollutants, SHS and some occupational inhaled pollutants may reduce fecundability. Future studies of SHS should use indoor air monitors and biomarkers to improve exposure assessment. Air monitors that capture real-time exposure can provide valuable insight about the role of indoor air pollution and are helpful in assessing the short-term acute effects of pollutants on TTP.

中文翻译：

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室内外空气污染与夫妻生育能力：系统评价

背景技术空气污染既损害感官又威胁人类健康。吸入的环境污染物可以是自然产生的，也可以是人为产生的，包括与交通相关的空气污染 (TRAP)、臭氧、颗粒物 (PM) 和挥发性有机化合物以及其他物质，包括二手烟产生的物质。对生殖和内分泌系统的空气污染的研究报告了 TRAP、二手烟 (SHS)、有机溶剂和生物质燃料烹饪与不良出生结果之间的关联。虽然一些证据表明空气污染会导致不孕不育，但现有的文献褒贬不一，并且报道了污染物的不同影响。目标和理由 尽管一些综述研究了常见的室外空气污染物与怀孕时间 (TTP) 之间的关联，但还没有全面的综述也包括接触室内吸入污染物，例如空气传播的职业毒物和二手烟。当前的系统综述总结了室外空气污染、二手烟和室内吸入空气污染与夫妇生育能力之间关联的证据强度，并确定了文献中的差距和局限性，为政策决策和未来研究提供信息。检索方法 我们对 6 个数据库进行了电子检索，查找自 1990 年以来发表的关于 TTP 或生育力以及空气污染、吸入和气雾化背景下的多种化学品的英文原始研究文章。使用 DistillerSR 软件开发了筛选、数据提取和研究质量的标准化表格，并一式两份填写。我们使用纽卡斯尔-渥太华量表来评估偏差风险，并根据空气污染和生育能力研究的具体方法学特征设计了额外的质量指标。结果 检索返回 5200 篇文章，其中 4994 篇在标题和摘要筛选方面被排除。经过全文筛选，剩下35篇论文进行数据提取和综合。另外独立确定了 3 篇符合标准的论文，并删除了 5 篇涉及多种暴露途径的论文，从 28 项研究中产生了 33 篇文章进行分析。有 8 篇论文研究了室外空气质量，6 篇论文研究了二手烟暴露，19 篇论文研究了室内空气质量。结果表明，室外空气污染与生育能力下降之间存在关联，包括 TRAP，特别是直径≤2.5 µm 的氮氧化物和 PM，以及暴露于 SHS 和甲醛。然而，不同研究之间的暴露窗口差异很大，暴露评估方法也有很大差异。几乎没有证据表明接触挥发性溶剂与生育力降低有关。更广泛的影响 有证据表明，接触室外空气污染物、二手烟和一些职业吸入污染物可能会降低生育力。未来的二手烟研究应使用室内空气监测器和生物标记物来改进暴露评估。捕捉实时暴露情况的空气监测仪可以提供有关室内空气污染作用的宝贵见解，并有助于评估污染物对 TTP 的短期急性影响。