Baur X, Huber H, Degens P O, Allmers H, Ammon J
Institute for Occupational Medicine, BGFA, Ruhr University, Bochum, Germany.
Am J Ind Med. 1998 Feb;33(2):114-22. doi: 10.1002/(sici)1097-0274(199802)33:2<114::aid-ajim3>3.0.co;2-y.
Inhalative methacholine challenge (MC) was performed in 229 subjects presumed to suffer from occupational asthma due to exposure to airborne latex allergens (n = 62), flour (n = 28), isocyanates (n = 114), or irritants in hairdressers' salons (n = 25). They were also subjected to specific challenges with the occupational agents they were exposed to, completed a questionnaire using an abbreviated version of the ATS-DLD, and were interviewed by an experienced physician. Bronchial hyperresponsiveness in MC was defined by the results obtained in a previous study with 81 healthy volunteers. The threshold in these controls was set at a cumulative MC dose of 0.3 mg, corresponding to a sensitivity of 95%. The main purpose of the study was to investigate whether the MC and/or the occupational asthma case history are reliable predictors of the specific challenge test outcomes. In 40-72% of examined subjects, workplace-related asthma complaints occurred, with bronchial hyperreactivity in the MC ranging from 48% to 61%. However, only 12-25% demonstrated a significant bronchoconstructive reaction in the specific challenge test. MC results are only moderately associated with workplace-related asthma case histories. Positive outcomes of challenges with occupational agents are well correlated with positive MC results plus occupational asthma case histories. The combination of MC and occupational asthma case history shows a relatively high specificity (62%, 86%, 80%), but the sensitivity was moderately low (83%, 71%, 52%). MC sensitivities were 92%, 71%, and 62% (case histories of hairdressers were not available). We conclude that in most cases, occupational asthma (as defined by a specific challenge test response) is combined with bronchial hyperresponsiveness and workplace-related asthmatic symptoms. However, subjects of each exposure group demonstrated bronchial hyperresponsiveness and complained of workplace-related asthmatic symptoms, but occupational asthma could not be proved in the specific challenge test. In subjects with a positive occupational asthma case history, a negative MC test result can almost rule out a positive specific challenges test result. Hence, the MC test can reduce performance of the laborious specific challenge test.
对229名被推测因接触空气中的乳胶过敏原（n = 62）、面粉（n = 28）、异氰酸酯（n = 114）或美发沙龙中的刺激物（n = 25）而患有职业性哮喘的受试者进行了吸入性乙酰甲胆碱激发试验（MC）。他们还接受了所接触职业性因素的特异性激发试验，使用美国胸科学会-丹麦胸科学会（ATS-DLD）简化版完成了一份问卷，并接受了一位经验丰富的医生的访谈。MC试验中的支气管高反应性根据先前一项对81名健康志愿者的研究结果来定义。这些对照的阈值设定为累积MC剂量0.3毫克，对应敏感度为95%。该研究的主要目的是调查MC试验和/或职业性哮喘病史是否是特异性激发试验结果的可靠预测指标。在40%至72%的受检受试者中，出现了与工作场所相关的哮喘症状，MC试验中的支气管高反应性范围为48%至61%。然而，只有12%至25%的受试者在特异性激发试验中表现出明显的支气管收缩反应。MC试验结果与工作场所相关的哮喘病史仅呈中度相关。职业性因素激发试验的阳性结果与MC试验阳性结果及职业性哮喘病史密切相关。MC试验和职业性哮喘病史的组合显示出相对较高的特异性（62%、86%、80%），但敏感度适中偏低（83%、71%、52%）。MC试验的敏感度分别为92%、71%和62%（美发沙龙工作人员的病史数据不可用）。我们得出结论，在大多数情况下，职业性哮喘（由特异性激发试验反应定义）与支气管高反应性及工作场所相关的哮喘症状并存。然而，每个暴露组的受试者都表现出支气管高反应性并抱怨有工作场所相关的哮喘症状，但在特异性激发试验中无法证实患有职业性哮喘。在职业性哮喘病史阳性的受试者中，MC试验结果为阴性几乎可以排除特异性激发试验结果为阳性。因此，MC试验可以减少繁琐的特异性激发试验的实施。
