Forastiere F, Pistelli R, Michelozzi P, Corbo G M, Agabiti N, Bertollini R, Ciappi G, Perucci C A
Epidemiologic Unit, Latium Regional Health Authority, Rome, Italy.
Chest. 1991 Oct;100(4):927-34. doi: 10.1378/chest.100.4.927.
A cross-sectional survey of the prevalence of asthma and bronchial hyperreactivity among schoolchildren (7 to 11 years old) was carried out in three areas of the Latium region (Central Italy). Out of 1,777 children tested with methacholine challenge (MCT), 15.1 percent had a 20 percent fall in FEV1 after a provocative concentration (PC20FEV1) of 4 mg/ml of methacholine or less; 69.7 percent had a PC20FEV1 less than 64.0 mg/ml, whereas 50.3 percent were nonresponders. Two continuous measures of bronchial responsiveness, the slope (percentage of change in FEV1 per mg/ml of methacholine) and the area under the dose response curve, were calculated in order to avoid the loss of information in nonresponders. Applying a receiver operating characteristic (ROC) curve analysis, the three estimators did not show any statistically significant difference in their overall performance in detecting asthma (ROC areas: PC20FEV1 = 0.683, slope = 0.681, area = 0.702 or asthma-like symptoms. The log transformation of slope, having a unimodal and slightly skewed shape, is an appealing continuous measure of bronchial responsiveness useful for epidemiologic studies. The final choice of an appropriate estimator of the concentration-response curve to methacholine, however, depends upon both the statistical tests or the modelling procedures to be used and clarification of the prognostic value of different indices of bronchial responsiveness.
在意大利中部拉齐奥地区的三个区域，对7至11岁学童的哮喘患病率和支气管高反应性进行了横断面调查。在1777名接受乙酰甲胆碱激发试验（MCT）的儿童中，15.1%的儿童在乙酰甲胆碱激发浓度（PC20FEV1）为4mg/ml或更低时，第一秒用力呼气容积（FEV1）下降了20%；69.7%的儿童PC20FEV1低于64.0mg/ml，而50.3%的儿童无反应。为避免无反应者信息丢失，计算了支气管反应性的两个连续指标，即斜率（每毫克/毫升乙酰甲胆碱引起的FEV1变化百分比）和剂量反应曲线下面积。应用受试者工作特征（ROC）曲线分析，这三个指标在检测哮喘（ROC面积：PC20FEV1 = 0.683，斜率 = 0.681，面积 = 0.702）或哮喘样症状方面的总体表现没有统计学显著差异。斜率的对数转换呈单峰且略偏态分布，是一种适用于流行病学研究的有吸引力的支气管反应性连续指标。然而，最终选择合适的乙酰甲胆碱浓度 - 反应曲线估计指标，既取决于要使用的统计检验或建模程序，也取决于明确不同支气管反应性指标的预后价值。
