Department of Sports Medicine, Osaka City University Graduate School of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
Respir Med. 2011 Jan;105(1):24-30. doi: 10.1016/j.rmed.2010.07.015. Epub 2010 Aug 12.
The present study aimed to illustrate differences in characteristics and perception of dyspnea between young atopic adults who have no history of asthma (never-asthmatics) with or without asymptomatic airway hyperresponsiveness (AHR) and those who had childhood asthma and consider themselves to be grown out of the disease (past-asthmatics).
Blood parameters, lung function and methacholine PC(20) were measured in 88 never-asthmatics and 24 past-asthmatics. A perception score of dyspnea at 20% fall in FEV(1) (PS(20)) was obtained by interpolation of the two last points on the perception (modified Borg scale)/fall in FEV(1) curve during methacholine challenge.
Thirty-one of 88 never-asthmatics and eighteen of 24 past-asthmatics exhibited AHR (PC(20) was <8 mg/ml). Higher levels of specific IgE to house dust mite in past-asthmatics were observed than never-asthmatics with and without AHR. Mean values of FEV(1) and FEF(25-75) (%predicted) were significantly lower in past-asthmatics than never-asthmatics without AHR, and the values in never-asthmatics with AHR were intermediate between never-asthmatics without AHR and past-asthmatics. PC(20) was not significantly different between past-asthmatics and never-asthmatics with AHR. Of particular interest was that PS(20) was significantly lower in never-asthmatics with AHR compared with past-asthmatics.
The present findings suggest the possibilities that presence or absence of past history of outgrow of childhood asthma might be associated with airway narrowing, sensitization to house dust mite and perception of dyspnea in young asymptomatic adults with atopy and AHR.
本研究旨在阐明无哮喘既往史（从未患过哮喘）的特应性年轻人中，无症状气道高反应性（AHR）与无 AHR 者之间，以及有儿童期哮喘既往史但认为已摆脱疾病（既往哮喘）者之间，呼吸困难特征和感知的差异。
共测量了 88 名从未患过哮喘者和 24 名既往哮喘者的血液参数、肺功能和乙酰甲胆碱 PC20。通过在乙酰甲胆碱激发过程中，对呼吸困难知觉（改良 Borg 量表）/用力肺活量下降曲线的最后两点进行内插，获得用力肺活量下降 20%时的呼吸困难知觉评分（PS20）。
88 名从未患过哮喘者中有 31 名和 24 名既往哮喘者中有 18 名存在 AHR（PC20<8mg/ml）。既往哮喘者的屋尘螨特异性 IgE 水平明显高于有和无 AHR 的从未患过哮喘者。与无 AHR 的从未患过哮喘者相比，既往哮喘者的用力肺活量和 25%~75%用力呼气量（预计值的%）的平均水平明显较低，而有 AHR 的从未患过哮喘者的水平则介于无 AHR 的从未患过哮喘者与既往哮喘者之间。PC20 在既往哮喘者和有 AHR 的从未患过哮喘者之间无显著差异。值得注意的是，有 AHR 的从未患过哮喘者的 PS20 明显低于既往哮喘者。
本研究结果提示，有或无儿童期哮喘既往史的存在可能与特应性、无症状、有 AHR 的年轻成年人的气道狭窄、对屋尘螨的致敏和呼吸困难感知有关。
