Increased asymptomatic airway hyper-responsiveness in obese individuals.

Objective. Asymptomatic airway hyper-responsiveness (AHR) represents a risk of further accelerated decline in lung function, and of asthma. Due to the fact that rare and contradictory results exist concerning the impact of obesity on BHR, we re-assessed the prevalence of bronchial hyper-responsiveness (BHR) in a large cohort of 60 lean, 84 overweight, and 360 class 1–3 obese non-asthmatic individuals, by coupled plethysmography and spirometry. Methods. Baseline-specific airway conductance (SGaw) and spirometric values were measured and then a methacholine challenge testing (MCT) was performed and considered as positive when a ≥200% increase in specific airway resistance (SRaw = 1/SGaw) was reached. Results. Compared to lean and overweight subjects, obese subjects of any class presented about a twice more frequent AHR (∼ 50% in obese vs. 17 and 26% in lean and overweight subjects, respectively). However, the bronchial sensitivity (methacholine dose doubling SRaw) and the shape of the relationship between S...