Effect of weight reduction on respiratory function and airway reactivity in obese women

Background: Population-based studies have documented an association between obesity and an increased prevalence of asthma in women. Methods: We prospectively studied 58 obese women with a body mass index of > 30 kg/m(2), 24 of whom had asthma, who were enrolled in an intensive 6-month weight loss program to determine whether loss of body mass would be correlated with improvements in bronchial reactivity, lung function, and disease-specific health status. Results: Patients lost air average of 20 kg over the 6-month period. For every 10% relative loss of weight, the FVC improved by 92 mL (p = 0.05) and the FEV1 improved by 73 mL (p = 0.04), however, bronchial reactivity did not significantly change with weight loss (p = 0.23). Patients who lost > 13% of their pretreatment weight experienced improvements in FEV1 (p = 0.01), FVC (p = 0.02), and total lung capacity (p = 0.05) compared to patients in the lowest quartile who failed to lose significant amounts of weight. Neither group experienced any significant change in methacholine responsiveness (p = 0.57). Patients who completed the 6-month weight loss program experienced improvements in respiratory health status, irrespective of weight loss. Conclusion: We concluded that weight loss can improve lung function in obese women, however, the improvements appear to be independent of changes in airway reactivity.