ESPE Abstracts

Introduction: Children with obesity are at higher risk of asthma. It is known the relationship between asthma and obesity in children demonstrated by altered lung function in obese compared to normal weight children. However, few studies have evaluated changes in lung function in obese asthmatic patients undergoing therapy.

Objective: The aimwas to evaluate the role of weight gain in the development of spirometry alterations in children with a history of asthma during treatment and secondarily the effects of the severity of weight gain on lung functions parameters.

Meterials and Methods: A total of 66 asthmatic subject (27F/39M; age: 6-16 years) undergoing therapy were recruited. Only obese and overweight children were enrolled in the study. The study population was then divided into three groups according to the tertiles of BMI-SDS (1^th tertile: 1.25 < BMI SDS < 1.73, 2^th tertile: 1.73 < BMI SDS < 2.21, 3^rd tertile: BMI SDS > 2.21). Anthropometric and biochemical measurements were calculated. A spirometry with pre- and postbronchodilator responses were performed to obtain lung function parameters. Particularly, Forced Expiratory Volume in 1 s (FEV₁), Forced Vital Capacity (FVC), Tiffeneau-Index (FEV₁/FVC ratio), Peak Expiratory flow (PEF) were calculated. In addition, Maximum Expiratory Flow at 75%, 50% and 25% of vital capacity (MEF 75, MEF50 e MEF25) reflecting conversely the small airways function was also obtained.

Results: The three groups were similar for FVC, FEV₁, FEV₁/FVC ratio and PEF (all P >0.05). In contrast, a significant difference was documented for MEF75, MEF50 e MEF25 (P≤0.05) showing the 3^rd tertile the lower values at baseline. These results were confirmed after postbronchodilator responses for MEF50%. A significant correlation was demonstrated between BMI-SDS and MEF25% (P = 0.02), MEF50% (P = 0.01) and MEF75% (P = 0.02). The BMI SDS was also significantly related to Delta-FVC% (P = 0.02), delta FEV₁% (P = 0.02), delta MEF50% (P = 0.04) and delta MEF25% (P = 0.01) expressing the differences among pre and post bronchodilator.

Conclusion: Obesity has significant effects on respiratory function, which contribute significantly to the burden of respiratory disease. Asthmatic patients showed a reduction of MEF75, MEF50 and MEF25 values which is also related to the severity of obesity. However, they do not show significant variation in terms of FVC, FEV1, FEV₁/FVC ratio and PEF at baseline and may have no signs of an obstructive airway diseases. The correlation between BMI-SDS and small and medium airways function parameters demonstrates an independent effects of obesity on lung dysfunction. Further studies are needed to better prevent and characterize these results.