Role of Leptin as a Link between Asthma and Obesity: A Systematic Review and Meta-Analysis

Abstract

Asthma and obesity are considered as highly prevalent diseases with a great impact on public health. Obesity has been demonstrated to be an aggravating factor in the pathogenesis of asthma. Adipose tissue secretes proinflammatory cytokines and mediators, including leptin, which may promote the development and severity of asthma in obese patients. This study is a systematic review and a meta-analysis based on the relationship between leptin and asthma during obesity. MEDLINE, Cochrane, EMBASE and CINAHL databases were used. Data heterogeneity was analyzed using Cochran’s Q and treatment effect with the DerSimonian and Laird method. Random effect analyses were carried out to test data sensitivity. Asymmetry was estimated using Begg’s and Egger’s tests. All studies showed significant differences in leptin levels. The effect of the measures (p < 0.001), data sensitivity (p < 0.05) and data asymmetry were statistically significant, as well as tBegg’s test (p = 0.010) and Egge’s test (p < 0.001). Despite the existing limiting factors, the results of this study support the relevant role of leptin in the pathophysiology of asthma in obese subjects. Nevertheless, further studies are needed to obtain better insight in the relationship between leptin and asthma in obesity.

Evaluating the Association of Obesity and Chronic Rhinosinusitis: A Systematic Review and Meta‐analysis

“…Prior studies have shown increased serum leptin levels in asthma patients compared to controls. A Meta‐analysis by Sánchez‐Ortega et al demonstrated through 15 studies that patients with asthma and obesity had elevated levels of leptin 9 . Consequently, research has focused on investigating the potential connection between systemic leptin levels and CRS 62‐64 .…”

“…A Meta-analysis by Sánchez-Ortega et al demonstrated through 15 studies that patients with asthma and obesity had elevated levels of leptin. 9 Consequently, research has focused on investigating the potential connection between systemic leptin levels and CRS. [62][63][64] In our Meta-analysis of 2 published studies, we reported that the mean serum leptin level in patients with CRSwNP was over 2-times greater compared to healthy controls independent of BMI.…”

“…8 A recent systematic review on this topic found that the majority of the fifteen studies assessing the mean serum leptin levels of asthma patients with obesity reported elevated levels compared to the control subjects. 9 Similarly, previous research has found that patients with nasal polyposis have higher levels of serum leptin compared to healthy control subjects. 10,11 Although obesity is a well-characterized risk factor for airway inflammatory diseases, specifically asthma, which has overlapping inflammation with CRS, its coprevalence and role in CRS is controversial.…”

“…Leptin is involved in increasing the production of proinflammatory cytokines such as tumor necrosis factor‐α, IL‐6, and IL‐12, which may play a role in obesity‐associated respiratory disease 8 . A recent systematic review on this topic found that the majority of the fifteen studies assessing the mean serum leptin levels of asthma patients with obesity reported elevated levels compared to the control subjects 9 . Similarly, previous research has found that patients with nasal polyposis have higher levels of serum leptin compared to healthy control subjects 10,11 …”

Obesity-related asthma: new insights leading to a different approach

“…In a recent meta-analysis by Sánchez-Ortega et al [38], substantial evidence supports Leptin's role as a mediator in asthma development and severity. This may be because of its functional similarities with IL-6, a well known pro-inflammatory cytokine associated with asthma, and its impact on the survival and proliferation of ILC2 and Th2 cells, which are key cell types in T2-high asthma.…”