# Reference Values for Methacholine Reactivity (SAPALDIA Study)

 Title: Reference Values for Methacholine Reactivity (SAPALDIA Study) Author: Jayet, Pierre-Yves; Schindler, Christian; Künzli, Nino; Zellweger, Jean-Pierre; Brändli, Otto; Perruchoud, André Paul; Keller, Roland; Ackermann-Liebrich, Ursula; Leuenberger, Philippe; Schwartz, Joel David Note: Order does not necessarily reflect citation order of authors. Citation: Jayet, Pierre-Yves, Christian Schindler, Nino Künzli, Jean-Pierre Zellweger, Otto Brändli, André Paul Perruchoud, Roland Keller, Joel Schwartz, Ursula Ackermann-Liebrich, Philippe Leuenberger, and SAPALDIA team. 2005. Reference values for methacholine reactivity (SAPALDIA study). Respiratory Research 6(1): 131. Full Text & Related Files: 1298336.pdf (360.6Kb; PDF) Abstract: Background: The distribution of airway responsiveness in a general population of non-smokers without respiratory symptoms has not been established, limiting its use in clinical and epidemiological practice. We derived reference equations depending on individual characteristics (i.e., sex, age, baseline lung function) for relevant percentiles of the methacholine two-point dose-response slope. Methods: In a reference sample of 1567 adults of the SAPALDIA cross-sectional survey (1991), defined by excluding subjects with respiratory conditions, responsiveness during methacholine challenge was quantified by calculating the two-point dose-response slope (O'Connor). Weighted L1-regression was used to estimate reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope. Results: Reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope were estimated using a model of the form a + b* Age + c* FEV$$_1$$ + d* (FEV$$_1$$)$$^2$$ , where FEV$$_1$$ corresponds to the pre-test (or baseline) level of FEV$$_1$$. For the central half of the FEV$$_1$$ distribution, we used a quadratic model to describe the dependence of methacholine slope on baseline FEV$$_1$$. For the first and last quartiles of FEV$$_1$$, a linear relation with FEV$$_1$$ was assumed (i.e., d was set to 0). Sex was not a predictor term in this model. A negative linear association with slope was found for age. We provide an Excel file allowing calculation of the percentile of methacholine slope of a subject after introducing age – pre-test FEV$$_1$$ – and results of methacholine challenge of the subject. Conclusion: The present study provides equations for four relevant percentiles of methacholine two-point slope depending on age and baseline FEV$$_1$$ as basic predictors in an adult reference population of non-obstructive and non-atopic persons. These equations may help clinicians and epidemiologists to better characterize individual or population airway responsiveness. Published Version: doi://10.1186/1465-9921-6-131 Other Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1298336/pdf/ Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8000913 Downloads of this work: