Association of Excess Weight and Degree of Airway Responsiveness in Asthmatics and Non-Asthmatics

Abstract

It is unclear whether obesity is associated with increasing degree of airway responsiveness in asthmatics. In this study, methacholine challenge test results of 1,725 subjects with respiratory symptoms were reviewed. Obesity was associated with asthma with an odds ratio of 1.72 (95% C.I. 1.36, 2.17). Although there was a significant difference in the degree of airway responsiveness between various body mass index categories of non-asthmatics (p = 0.01), no significant difference was noted among asthmatics (p = 0.93). A weakly significant interaction between asthma status and body mass index on the degree of airway responsiveness was noted (p = 0.08).

Airway Hyperresponsiveness Is Negatively Associated with Obesity or Overweight Status in Patients with Asthma

“…In an earlier report, BMI was negatively correlated with the presence of AHR confirmed by MBPT [11], and others have reported that obesity is a risk factor for asthma and wheezing, but not for AHR [2,8,9,10,11,20,21]. However, many studies have shown a link between obesity and increases in both AHR and the prevalence of asthma in the general population [4,5,6,7].…”

“…In studies assessing obesity and asthma, the definition of asthma is critical because obesity can mimic asthma by causing wheezing [10,24,25]. Studies in asthmatic patients have consistently shown no relationship, or even a negative association, between obesity and AHR [2,8,9,10,11]. It is inferred that obesity has different effects on AHR in asthmatic individuals compared with non-asthmatic individuals.…”

“…Asthma is an airway disease characterized by chronic airway inflammation and airway hyperresponsiveness (AHR), but the evidence regarding a relationship between obesity and AHR has been inconsistent [5]. Some studies have reported that obesity increased AHR and that weight gain was positively related to the prevalence of AHR in general populations [4,5,6,7]; in contrast, other studies have shown no relationship, or even a negative association, between obesity and the presence of AHR in asthma patients [2,8,9,10,11]. Furthermore, there is evidence indicating that the chronic inflammation associated with obesity lessens Th2 inflammation [12,13,14], which is closely related to AHR in asthma.…”

Modulation of inflammation and immunity by dietary conjugated linoleic acid

“…Leptin levels increase with obesity, resulting in a subsequent upregulation of pro-inflammatory cytokine production (Sood et al, 2006). Contrarily, obesity-related decrease in adiponectin levels can negatively regulate allergic airway inflammation (Shore et al, 2006).…”

Adiponectin attenuates human eosinophil adhesion and chemotaxis: implications in allergic inflammation

“…A recent meta-analysis of a prospective epidemiologic study demonstrated a clear dose-response relationship between body mass index (BMI) and incident asthma [2]. Obesity has also been associated with airway hyperresponsiveness [3][4][5] and reduced response to asthma medication [6,7]. Moreover, intervention consisting of weight reduction in obese asthmatics improved morbidity, lung function and the number of exacerbations [8].…”