School of Population and Public Health, University of British Columbia, British Columbia, Canada.
Environ Health Perspect. 2010 Feb;118(2):284-90. doi: 10.1289/ehp.0900916.
There is increasing recognition of the importance of early environmental exposures in the development of childhood asthma. Outdoor air pollution is a recognized asthma trigger, but it is unclear whether exposure influences incident disease. We investigated the effect of exposure to ambient air pollution in utero and during the first year of life on risk of subsequent asthma diagnosis in a population-based nested case-control study.
We assessed all children born in southwestern British Columbia in 1999 and 2000 (n = 37,401) for incidence of asthma diagnosis up to 34 years of age using outpatient and hospitalization records. Asthma cases were age- and sex-matched to five randomly chosen controls from the eligible cohort. We estimated each individual's exposure to ambient air pollution for the gestational period and first year of life using high-resolution pollution surfaces derived from regulatory monitoring data as well as land use regression models adjusted for temporal variation. We used logistic regression analyses to estimate effects of carbon monoxide, nitric oxide, nitrogen dioxide, particulate matter <or= 10 microm and <or= 2.5 microm in aerodynamic diameter (PM10 and PM2.5), ozone, sulfur dioxide, black carbon, woodsmoke, and proximity to roads and point sources on asthma diagnosis.
A total of 3,482 children (9%) were classified as asthma cases. We observed a statistically significantly increased risk of asthma diagnosis with increased early life exposure to CO, NO, NO2, PM10, SO2, and black carbon and proximity to point sources. Traffic-related pollutants were associated with the highest risks: adjusted odds ratio = 1.08 (95% confidence interval, 1.041.12) for a 10-microg/m3 increase of NO, 1.12 (1.071.17) for a 10-microg/m3 increase in NO2, and 1.10 (1.061.13) for a 100-microg/m3 increase in CO. These data support the hypothesis that early childhood exposure to air pollutants plays a role in development of asthma.
越来越多的人认识到早期环境暴露对儿童哮喘发展的重要性。室外空气污染是公认的哮喘诱因，但尚不清楚暴露是否会影响疾病的发生。我们在一项基于人群的巢式病例对照研究中，调查了宫内和生命第一年暴露于环境空气污染对随后哮喘诊断风险的影响。
我们评估了 1999 年和 2000 年在不列颠哥伦比亚省西南部出生的所有儿童（n = 37401），直到 34 岁时的哮喘诊断发病率，使用门诊和住院记录。哮喘病例按年龄和性别与合格队列中随机选择的 5 名对照匹配。我们使用高分辨率污染表面，该表面源自监管监测数据以及土地利用回归模型，对妊娠期和生命第一年的个体暴露于环境空气污染进行了估计，该模型根据时间变化进行了调整。我们使用逻辑回归分析来估计一氧化碳、一氧化氮、二氧化氮、空气动力学直径<或= 10 微米和<或= 2.5 微米的颗粒物（PM10 和 PM2.5）、臭氧、二氧化硫、黑碳、木烟以及接近道路和点源对哮喘诊断的影响。
共有 3482 名儿童（9%）被归类为哮喘病例。我们观察到，随着生命早期接触 CO、NO、NO2、PM10、SO2 和黑碳以及接近点源，哮喘诊断的风险呈统计学显著增加。交通相关污染物与最高风险相关：NO 每增加 10μg/m3，调整后的比值比= 1.08（95%置信区间，1.041.12）；NO2 每增加 10μg/m3，调整后的比值比= 1.12（1.071.17）；CO 每增加 100μg/m3，调整后的比值比= 1.10（1.061.13）。这些数据支持了这样的假设，即儿童早期暴露于空气污染物在哮喘的发展中起作用。
