Elsevier

Pulmonary Pharmacology & Therapeutics

Chronic cough and obesity

Abstract

With respective prevalence of 13% and 9.6%, obesity and chronic cough are two common conditions worldwide. The crucial role of obesity has been highlighted in the development and progression of many respiratory diseases. According to the results of epidemiological studies, obesity, particularly abdominal obesity, may also be associated with chronic cough (CC). CC seems to be more severe in obese patients compared to normal-weight subjects. The management of CC may differ slightly in obese patients compared to non-obese patients. Indeed, asthma and reflux diseases, which are considered key factors in the onset of CC, are characterised by more severe symptoms in obese patients. Asthma is associated with a resistance to usual treatments in obese patients but no data are available on the effect of inhaled therapies in obese subjects with cough variant asthma. Other emergent causes of CC have been reported in obese patients. Obstructive sleep apnoea and diabetes may also be involved in the development of CC and should be taken into account in obese patients with CC. The beneficial effect of weight loss on chronic cough has been suggested.

Introduction

Obesity plays an important role in the development and progression of respiratory diseases. In asthma, obesity is considered a major comorbidity that exacerbates respiratory symptoms [1]. Many epidemiological studies have shown that obese patients have a higher risk of developing asthma than the general population demonstrating that obesity is involved in the development of asthma [2]. It is also well established that asthma associated with obesity is a phenotype with more difficult-to-treat asthma compared to non-obese subjects [3,4]. Obesity also plays an important role in chronic obstructive pulmonary disease (COPD) because it is associated with worse COPD-related outcomes and specific management of obesity reduces the risk of acute exacerbation of COPD [5]. In many lung diseases, weight loss is required to improve respiratory symptoms.

Chronic cough is a common entity in respiratory medicine. It is a complex disorder, the management of which has recently been defined in the guidelines of the American College of Chest Physicians [6]. All the steps covering the investigations and initial treatments are detailed in these guidelines. However, body mass index (BMI) measurement and assessment of obesity markers are not included in the evaluation of patients with chronic cough. As with other respiratory diseases, should obesity be taken into account in the management of chronic cough? Does obesity impact on the development of chronic cough? In this review, the link between chronic cough and obesity will be discussed as well as the clinical approach to an obese patient with chronic cough.

Section snippets

Epidemiological data on chronic cough and obesity

Over the last 40 years, obesity has tripled worldwide and is now considered a genuine public health problem [7]. In 2016, more than 1.9 billion people were overweight and more than 650 million were obese according to the World Health Organisation (WHO) [7]. Thirty-nine percent (39%) of adults are overweight and 13% are obese, worldwide [7]. Overweight and obesity are significantly associated with morbidity and mortality rates and a high BMI accounts for 4.0 million deaths globally [8].

Specificity of the clinical approach towards chronic cough in obese patients

As explained above, obesity is a very common disease worldwide but its prevalence in patients with chronic cough has been inadequately studied. In the epidemiological study carried out in the UK in 2006, 20% of patients with chronic cough were obese [14]. This means that the proportion of obese patients with chronic cough is probably high in clinical practice. Should we manage chronic cough in obese patients differently from non-obese patients? The guidelines on chronic cough management may be

Chronic cough and OSA

It is a well-established fact that obesity is a risk factor for the development and progression of obstructive sleep apnoeas (OSA) [32]. The prevalence of OSA in obese patients is nearly twice that of normal-weight adults [33]. An association between chronic cough and OSA was initially proposed in 2007 [34]. Birring et al. reported 4 patients presenting with an isolated chronic cough who were subsequently found to have obstructive sleep apnoea. Cough improved rapidly with nocturnal continuous

Chronic cough and diabetes

Obesity is a recognised risk factor of type 2 diabetes mellitus [45]. In a study carried out in 33,939 men, obesity was associated with type 2 diabetes with an OR of 3.88 [95% CI 1.94–7.77] [46]. Recently, it has been suggested that type 2 diabetes may be a risk factor of chronic cough. Indeed, in a cross-sectional study, self-reported chronic cough/phlegm was more common in diabetic patients compared to the general population but only in patients 45–64 years old [47]. Indeed, in those

Weight loss and chronic cough

Given the fact that inhaled corticosteroids are less effective in obese patients with asthma, weight loss has been suggested as an option in obese patients with asthma [51]. The combination of dietary intervention and exercise has been shown to improve asthma control in obese patients [52]. Despite a lack of evidence, diet and exercise intervention may be considered in obese patients with chronic cough associated with asthma. A significant improvement in the ACQ (Asthma Control Questionnaire)

Conclusion

The link between obesity and chronic cough has been suggested in the literature. In the guidelines on chronic cough management, no difference has been highlighted between obese and normal-weight individuals. However, emergent causes of chronic cough such as OSA or diabetes should be taken into account in clinical practice. The beneficial effect of weight loss has been demonstrated in many obesity-related diseases. Weight-loss procedures may constitute part of the treatment of chronic cough in

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