Dietary restriction and exercise improve airway inflammation and clinical outcomes in overweight and obese asthma: a randomized trial

Background: Obesity and asthma are associated conditions; however, the mechanisms linking the two remain unclear. Few studies have examined the effects of weight loss on inflammation and clinical outcomes in obese-asthma. Objective: To compare the effects of weight loss achieved by dietary restriction, exercise or combined dietary restriction and exercise on airway inflammation and clinical outcomes in overweight and obese adults with asthma. Methods: Participants (n = 46; 54.3% female, body mass index (mean +/- SD) 33.7 +/- 3.5 kg/m(2) ) were randomized to complete a 10-week dietary, exercise or combined dietary and exercise intervention. Dual-energy x-ray absorptiometry was performed, the Juniper Asthma Control Questionnaire and Juniper Asthma Quality of Life Questionnaire completed and inflammatory markers, dietary intake and physical activity measured. The trial was registered with the Australian Clinical Trials Registry: ACTRN12611000235909. Results: Retention was 82.6%. Mean +/- SD weight loss was 8.5 +/- 4.2%, 1.8 +/- 2.6% and 8.3 +/- 4.9% after the dietary, exercise and combined interventions respectively. Asthma control improved after the dietary (mean +/- SD; -0.6 +/- 0.5, P