Air Health Science Division, Health Canada, Ottawa, Ontario, Canada; School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Ontario, Canada; Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada.
Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada.
Environ Int. 2021 Jul;152:106486. doi: 10.1016/j.envint.2021.106486. Epub 2021 Mar 5.
Several studies have found positive associations between outdoor fine particulate air pollution (≤2.5 μm, PM) and childhood asthma incidence. However, the impact of PM composition on children's respiratory health remains uncertain.
We examined whether joint exposure to PM mass concentrations and its major chemical components was associated with childhood asthma development.
We conducted a population-based cohort study by identifying 1,130,855 singleton live births occurring between 2006 and 2014 in the province of Ontario, Canada. Concentrations of PM and its seven major chemical components were assigned to participants based on their postal codes using chemical transport models and remote sensing. The joint impact of outdoor PM concentrations and its major components and childhood asthma incidence (up to age 6) were estimated using Cox proportional hazards models, allowing for potential nonlinearity.
We identified 167,080 children who developed asthma before age 6. In adjusted models, outdoor PM mass concentrations during childhood were associated with increased incidence of childhood asthma (Hazard Ratio (HR) for each 1 μg/m increase = 1.026, 95% CI: 1.021-1.031). We found that the joint effects of PM and its components on childhood asthma incidence may be 24% higher than the conventional approach. Specific components/source markers such as black carbon, ammonium, and nitrate appeared to play an important role.
Early life exposure to PM and its chemical components is associated with an increased risk of asthma development in children. The heterogeneous nature of PM should be considered in future health risk assessments.
多项研究发现，室外细颗粒物空气污染（≤2.5μm，PM）与儿童哮喘发病率之间存在正相关关系。然而，PM 成分对儿童呼吸健康的影响仍不确定。
我们研究了 PM 质量浓度及其主要化学成分的联合暴露是否与儿童哮喘发展有关。
我们进行了一项基于人群的队列研究，在加拿大安大略省确定了 2006 年至 2014 年间出生的 1,130,855 名单胎活产儿。使用化学传输模型和遥感技术，根据参与者的邮政编码将 PM 及其七种主要化学成分的浓度分配给参与者。使用 Cox 比例风险模型估计室外 PM 浓度及其主要成分与儿童哮喘发病率（至 6 岁）的联合影响，允许存在潜在的非线性。
我们确定了 167,080 名在 6 岁前患有哮喘的儿童。在调整后的模型中，儿童期室外 PM 质量浓度与儿童哮喘发病率增加相关（每增加 1μg/m 的危害比（HR）=1.026，95%CI：1.021-1.031）。我们发现，PM 及其成分对儿童哮喘发病率的联合影响可能比传统方法高 24%。特定成分/源标志物，如黑碳、铵和硝酸盐，似乎起着重要作用。
儿童早期暴露于 PM 及其化学成分与哮喘发病风险增加有关。在未来的健康风险评估中，应考虑 PM 的异质性。
