Folinsbee L J
Clinical Research Branch, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711.
Toxicol Ind Health. 1992 Sep-Oct;8(5):273-83.
A number of reports have suggested that exposure to nitrogen dioxide (NO2) may cause increased airways responsiveness (AR). Twenty studies of asthmatics and five studies of healthy subjects exposed to NO2 were used to test this hypothesis using a simple method of meta-analysis. Individual data were obtained for the above studies and the direction of change in AR was determined for each subject. Only studies with available individual data were used. Subjects from these studies whose directional change in AR could not be determined were excluded. The fraction of positive responses (i.e. increased AR) was determined for all subjects within a group and tested for significance using a sign test. Data were also grouped according to NO2 concentration and by whether the exposure included exercise. There was an overall trend among asthmatics for AR to increase (60%) but this was primarily due to increased AR seen in resting exposures (70%). Among healthy subjects AR also increased with NO2 exposure but only at concentrations above 1.0 ppm. This analysis suggests that NO2 exposure causes increased airway responsiveness in healthy and asthmatic subjects but that exercise during exposure may modify this response in asthmatics.
多项报告表明，接触二氧化氮（NO₂）可能会导致气道反应性（AR）增强。本研究采用一种简单的荟萃分析方法，对20项针对哮喘患者以及5项针对接触NO₂的健康受试者的研究进行分析，以验证这一假设。获取了上述研究的个体数据，并确定了每个受试者AR的变化方向。仅使用了具有可用个体数据的研究。排除了这些研究中无法确定AR方向变化的受试者。确定了一组内所有受试者的阳性反应比例（即AR增加），并使用符号检验进行显著性检验。数据还根据NO₂浓度以及接触是否包括运动进行了分组。哮喘患者中总体存在AR增加的趋势（60%），但这主要是由于静息接触时AR增加（70%）所致。在健康受试者中，AR也随NO₂接触而增加，但仅在浓度高于1.0 ppm时出现。该分析表明，接触NO₂会导致健康受试者和哮喘患者的气道反应性增加，但接触期间的运动可能会改变哮喘患者的这种反应。
