Table 1.
Major clinical and basic research studies highlighting the association between obesity and asthma.
| Author | Major Finding |
|---|---|
| Clinical Research | |
| Shaheen et al., 1999 [4] | Higher BMI during adulthood is significantly associated with increased asthma prevalence |
| Rönmark et al., 2005 [6] | Obesity (BMI ≥ 30) and overweightness (BMI 25.0–29.9) increase asthma risk by 2.7- and 2.0-fold, respectively, as compared with normal-weight individuals |
| Jones et al., 2006 [10] | Lung volumes, including functional residual capacity (FRC) and expiratory reserve volume (ERV), reduce exponentially with increasing BMI |
| Sood et al., 2006 [11] | Serum leptin level and BMI are positively associated with asthma in women |
| Komakula et al., 2007 [12] | BMI is associated with lower exhaled nitric oxide and higher levels of oxidative stress markers, 8-isoprostanes, in exhaled breath |
| Thyagarajan et al., 2008 [13] | Increase in BMI is associated with reduced lung function by lowering FEV1 and FVC |
| Ciprandi et al., 2009 [14] | Increased BMI is significantly associated with enhanced bronchial hyperresponsiveness in asthma patients |
| Dixon et al., 2011 [15] | Bariatric surgery has a beneficial impact on improving airway hyperresponsiveness in non-atopic obese asthmatic individuals |
| Schatz et al., 2013 [16] | Increased BMI is associated with enhanced seasonal asthma exacerbation risk in pediatric and adult populations having persistent asthma |
| Sanchez Jimenze et al., 2014 [17] | Insulin resistance increases the risk of allergic asthma in obese children and adolescents. Increased waist circumference is associated with reduced FVC and FEV1 |
| Chen et al., 2017 [18] | Asthmatic children show higher risk (51%) of obesity during their later childhood and adolescence when compared with non-asthmatic children |
| To et al., 2018 [19] | Obesity is independently associated with reduced asthma control and increased exacerbation in severely asthmatic adult females |
| Luthe et al., 2018 [20] | Obese asthmatic individuals have increased acute severity of asthma that is associated with the enhanced use of mechanical ventilation and longer periods of hospitalization as compared with lean asthmatic individuals |
| Saheb Sharif Askari et al., 2019 [21] | Obese asthmatic children with BMI ≥ 85% are associated with increased asthma severity and enhanced frequency of hospital visits due to asthma as compared with lean individuals |
| Michalovich et al., 2019 [22] | Both obesity and asthma contribute additively to enhancing inflammation and microbiota alternation |
| Basic Research | |
| Calixto et al., 2010 [23] | High-fat-diet-induced obesity is associated with increased eosinophil migration from the bone marrow into lung tissue and enhanced expression of Th1 and Th2 cytokines, resulting in a prolonged stay of eosinophils in peribronchiolar segments of lungs |
| Dietze et al., 2012 [24] | HFD-induced obesity reduces the allergic sensitization threshold and increases eosinophilic airway inflammation in mice |
| Suzukawa et al., 2015 [25] | Obesity-associated hormone, leptin, promotes pro-the inflammatory phenotype, proliferation, migration, and apoptosis of airway epithelial cells |
| Diaz et al., 2015 [26] | Obese mice show reduced adiponectin level in plasma, decreased and increased infiltration of eosinophil and macrophages, respectively, into the lungs and BAL, increased expression of markers of macrophages (M1 and M2) in the lungs, and elevated expression of cytokines (Th1 and Th2) in BAL, and reduced response to dexamethasone as compared with lean mice upon house mite dust exposure |
| Zheng et al., 2016 [27] | Leptin augments inflammation in allergic asthma by activating lung immune cells |
| Silva et al., 2017 [28] | Obesity augments OVA-induced allergic inflammation in mice by prolonging the immune response by Th cells and increasing mixed granulocyte influx, macrophage activation, and mucous production |
| Andre et al., 2017 [29] | HFD-fed obese–asthmatic mice show impaired insulin signaling in their lungs due to reduced phosphorylation and enhanced tyrosine nitration of AKT, insulin receptor β, and insulin receptor substrate-1 as compared with lean-asthmatic mice |
| Orfanos et al., 2018 [30] | Airway smooth muscle cells of obese individuals show increased hyperresponsiveness to contractile antagonists as compared with those of lean individuals |
| Watanabe et al., 2019 [31] | Leptin induces the differentiation of lung fibroblasts by increasing the production of different inflammatory chemokines and cytokines |
Abbreviations: BMI: Body mass index; FEV1: Forced expiratory volume in 1 s; FVC: Forced vital capacity; Th: T Helper cell; HFD: High-fat diet; BAL; Bronchoalveolar lavage; OVA: Ovalbumin.