Pulmonary function and blood gases after gastric bypass and lifestyle intervention: a comparative study
Article first published online: 8 JUL 2013
© 2013 The Authors. Clinical Obesity © 2013 International Association for the Study of Obesity
Volume 3, Issue 5, pages 117–123, October 2013
How to Cite
Gabrielsen, A.-M., Lund, M. B., Kongerud, J., Viken, K. E., Røislien, J., Hjelmesæth, J. and Hofsø, D. (2013), Pulmonary function and blood gases after gastric bypass and lifestyle intervention: a comparative study. Clinical Obesity, 3: 117–123. doi: 10.1111/cob.12024
- Issue published online: 17 SEP 2013
- Article first published online: 8 JUL 2013
- Manuscript Accepted: 27 MAY 2013
- Manuscript Revised: 18 APR 2013
- Manuscript Received: 23 JAN 2013
- Bariatric surgery;
- morbid obesity;
- respiratory function tests and blood gas analysis;
- weight loss
What is already known about this subject
- Impaired lung function associated with obesity improves with weight loss.
What this study adds
- This is the first study to compare the effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases.
- Arterial oxygenation and pulmonary function improved to a greater extent after gastric bypass than after lifestyle intervention.
- The superiority of surgical treatment might be mediated by greater weight loss after gastric bypass.
Impaired lung function associated with obesity improves with weight loss. The effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases have not previously been subjected to comparative examination. In this 1-year non-randomized controlled clinical trial (ClinicalTrials.gov identifier NCT00273104), 139 morbidly obese subjects (19–66 years, mean [standard deviation] body mass index [BMI] 45.1 kg m−2 [5.6], 107 women) were treated with either Roux-en-Y gastric bypass surgery (n = 76) or intensive lifestyle intervention (n = 63). Mean weight reduction was 30 (8)% and 8 (9)%, respectively. Dynamic and static lung volumes, gas diffusing capacity and arterial blood gases were measured. Compared with lifestyle intervention, surgery resulted in a significantly greater increase in forced vital capacity (mean [95% confidence interval] between-group difference, 7 [4–10]%), forced expiratory volume in 1 s (7 [5–9]%), total lung capacity (5 [1–8]%), vital capacity (7 [4–9]%), functional residual capacity (18 [12–24]%), expiratory reserve volume (48 [30–66]%) and partial pressure of oxygen in arterial blood (0.5 [0.0–1.0] kPa). These associations either disappeared or diminished after adjusting for weight loss. Reduced central adiposity (waist circumference and waist-to-hip ratio) and systemic inflammation (C-reactive protein and adiponectin) had no effect on pulmonary function beyond the effect of reduced general adiposity (BMI). In morbidly obese subjects, gastric bypass surgery is more effective than lifestyle intervention at improving arterial oxygenation and pulmonary function. The effect might be mediated by greater weight loss after surgical treatment.