Subjects attended an initial screening visit at which demographic,
anthropometric and clinical data were recorded.
Subjects were selected if inclusion and exclusion criteria were
met, until the numbers of male and female study subjects with
normal, overweight and obese body habitus were balanced.
Inclusion criteria were being healthy and 20–50 yrs of age.
To decrease the likelihood of subclinical airways disease,
exclusion criteria were: current respiratory symptoms; history
of respiratory disease; ex-smokers with a smoking history
of .10 pack-yrs or who had smoked in the last year; cardiac
or neurological comorbidity; structural abnormalities of the
chest wall; and an exhaled nitric oxide concentration of
.35 ppb [15] or a positive methacholine challenge [16]. The
study was approved by the Lower South Ethics Committee
(Dunedin, New Zealand) and all participants gave written
informed consent