Reference equations for respiratory system resistance and reactance in adults

Aim: To determine reference equations for respiratory system resistance and reactance in a large randomly selected sample from a general, predominantly Caucasian population. Methods: A prospective respiratory health survey of the general population in Busselton, Western Australia, was conducted between 2005 and 2007. Subjects had measures of spirometry, and resistance and reactance at 6, 11, 19 Hz. Eligible subjects were never smokers, with no history of respiratory disease, no symptoms of cough, shortness of breath or chest tightness in the previous 12 months, and no respiratory tract infections in the previous 4 weeks. Results: 904 Eligible subjects (341 male) aged 18-92 years had technically satisfactory measurements. Reference equations were established for males and females separately. Both resistance and reactance were predicted by height and weight. Age was a predictor of reactance only. Conclusions: These data provide reference equations for forced oscillatory parameters, in well-characterized Caucasian subjects, with no respiratory symptoms, from a large general population. (C) 2010 Elsevier B.V. All rights reserved.