Islam Talat, Gauderman W James, Berhane Kiros, McConnell Rob, Avol Ed, Peters John M, Gilliland Frank D
Department of Preventive Medicine, Keck School of Medicine, Los Angeles, California 90033, USA.
Thorax. 2007 Nov;62(11):957-63. doi: 10.1136/thx.2007.078964. Epub 2007 May 21.
The interrelationships between air pollution, lung function and the incidence of childhood asthma have yet to be established. A study was undertaken to determine whether lung function is associated with new onset asthma and whether this relationship varies by exposure to ambient air pollutants.
A cohort of children aged 9-10 years without asthma or wheeze at study entry were identified from the Children's Health Study and followed for 8 years. The participants resided in 12 communities with a wide range of ambient air pollutants that were measured continuously. Spirometric testing was performed and a medical diagnosis of asthma was ascertained annually. Proportional hazard regression models were fitted to investigate the relationship between lung function at study entry and the subsequent development of asthma and to determine whether air pollutants modify these associations.
The level of airway flow was associated with new onset asthma. Over the 10th-90th percentile range of forced expiratory flow over the mid-range of expiration (FEF(25-75), 57.1%), the hazard ratio (HR) of new onset asthma was 0.50 (95% CI 0.35 to 0.71). This protective effect of better lung function was reduced in children exposed to higher levels of particulate matter with an aerodynamic diameter <2.5 microm (PM(2.5)). Over the 10th-90th percentile range of FEF(25-75), the HR of new onset asthma was 0.34 (95% CI 0.21 to 0.56) in communities with low PM(2.5) (<13.7 microg/m(3)) and 0.76 (95% CI 0.45 to 1.26) in communities with high PM(2.5) (> or = 13.7 microg/m(3)). A similar pattern was observed for forced expiratory volume in 1 s. Little variation in HR was observed for ozone.
Exposure to high levels of PM(2.5) attenuates the protective effect of better lung function against new onset asthma.
空气污染、肺功能与儿童哮喘发病率之间的相互关系尚未明确。开展了一项研究以确定肺功能是否与新发哮喘相关，以及这种关系是否因暴露于环境空气污染物而有所不同。
从儿童健康研究中确定了一组9至10岁、研究开始时无哮喘或喘息的儿童，并对其进行了8年的随访。参与者居住在12个社区，这些社区的环境空气污染物种类繁多且进行了连续测量。每年进行肺活量测定测试并确定哮喘的医学诊断。采用比例风险回归模型来研究研究开始时的肺功能与随后哮喘发病之间的关系，并确定空气污染物是否会改变这些关联。
气道气流水平与新发哮喘相关。在呼气中期用力呼气流量（FEF(25 - 75)）的第10 - 90百分位数范围内（57.1%），新发哮喘的风险比（HR）为0.50（95%置信区间0.35至0.71）。在暴露于空气动力学直径<2.5微米的颗粒物（PM(2.5)）水平较高的儿童中，较好肺功能的这种保护作用减弱。在FEF(25 - 75)的第10 - 90百分位数范围内，PM(2.5)水平低（<13.7微克/立方米）的社区中，新发哮喘的HR为0.34（95%置信区间0.21至0.56），而在PM(2.5)水平高（≥13.7微克/立方米）的社区中为0.76（95%置信区间0.45至1.26）。对于1秒用力呼气量也观察到了类似模式。对于臭氧，HR几乎没有变化。
暴露于高水平的PM(2.5)会减弱较好肺功能对新发哮喘的保护作用。
