Obese Asthma Syndrome, Glucocorticoids, and Vitamin D: Mechanisms and Implications

The obese asthma syndrome (OAS) is characterized by increased airway inflammation and impaired lung function. Obesity-induced inflammation, characterized by elevated pro-inflammatory cytokines and reduced anti-inflammatory adipokines, contributes to airway inflammation and asthma symptoms. Asthmatic patients with obesity often have a poor response to inhaled corticosteroids (ICS), which are the mainstay of asthma treatment. They achieve less asthma control, more hospitalizations, and experience a poorer quality of life. The detrimental effects of obesity on lung function and the additive or synergistic effects of systemic inflammation contribute to this reduced response to glucocorticoids. Additionally, studies have suggested a potential association between vitamin D deficiency, obesity, and asthma exacerbations. Low vitamin D levels have also been linked to glucocorticoid resistance, while in vitro evidence suggests that vitamin D can enhance the effectiveness of glucocorticoids. Weight loss through bariatric surgery shows promising results in improving asthma control and reducing airway inflammation.