Abstract
: We investigated the association between airway hyperresponsiveness (AHR) and obesity in adults referred for confirmation of asthma diagnosis. Data were analyzed for obesity class I (body mass index [BMI] 30-34.9 kg/m2), class II (BMI >/= 35-39.9 kg/m2), and class III (BMI >/= 40 kg/m2). Of 861 subjects, 401 demonstrated AHR; the mean dose of methacholine was 4.16 +/- 2.55 mg/mL. A significant association between obesity and AHR was evident for all subjects: the odds ratio was 1.37 (95% CI 1.02-1.82; p = .0317). One unit of increased BMI (1 kg/m2) was associated with a 3.1% increase in AHR risk (95% CI 1.01-1.05, p < .005). The odds ratio increased from 1.86 (95% CI 1.27-1.76; p = .0012) for class I to 2.61 (95% CI 1.48-4.60; p = .0006) for class III. Obesity was found to be associated with AHR and appears to be a risk factor for asthma.