The prevalence of obesity has increased dramatically over the last decades. Over 1.6 billion adults worldwide are overweight, of which 400 million are obese. Obesity has emerged as an important risk factor for a wide range of chronic medical conditions, including cardiovascular and metabolic diseases, hypercoagulable states, and cancer. Its association with the respiratory system diseases, including obstructive sleep apnea syndrome (OSAS), obesity hypoventilation syndrome (OHS), chronic obstructive pulmonary disease (COPD), asthma, pulmonary embolism, and aspiration pneumonia, is now widely recognized. In many instances, obesity influences the development and presentation of disease and is associated with the outcome of symptomatic improvement.

With the rise of weight, the lung volume decreases. This leads to more restricted air entry. In addition, fat tissue in the abdominal wall and around the abdominal organs hampers movement of the diaphragm and reduces the lung expansion. However, the molecular mechanisms of obesity in respiratory disorders have not been fully elucidated. This special issue will highlight the current state of knowledge about obesity in the pathophysiology of multiple respiratory disorders. We invite authors to contribute original research articles as well as review articles that will emphasize understanding the molecular mechanisms underlying the relationship between lung biology and obesity.

Potential topics include but are not limited to the following:

• Pulmonary function and the metabolic effects of obesity
• Obstructive sleep apnea syndrome
• Obesity hypoventilation syndrome
• Effect of obesity on chronic obstructive pulmonary disease with obesity
• Effect of obesity on asthma with obesity
• Effect of obesity on pulmonary embolism and obesity
• Effect of obesity on aspiration pneumonia and obesity