Let's talk about obesity in respiratory disease

Obesity is a chronic and relapsing condition where weight loss is often associated with regain of weight over time.1 The prevalence of obesity is increasing, and it is now referred to as a global pandemic.2 Prevalence data suggest that by 2035, over 4 billion people worldwide may be living with overweight (BMI ≥25 kg/m2) or obesity, compared with the 2020 prevalence of 2.6 billion.3 The prevalence of obesity (BMI ≥30 kg/m2) alone is expected to increase from 14% to 24% of the world's population over this time, leading to almost 2 billion adults, children, and adolescents living with obesity by 2035. Whilst obesity is currently defined as a BMI ≥30 kg/m2, experts call for a move away from this sole criterion for diagnosis, rather clinical obesity should be conceptualized as a chronic disease, not based on body weight but on excess or dysfunctional adiposity.4 To combat the global and increasing prevalence, the World Obesity Federation in collaboration with its global members, convenes a World Obesity Day on the 4th of March. World Obesity Day is a unified day of action that calls for a cohesive, cross-sector response. https://www.worldobesityday.org/about-wod. This year's theme is 'let's talk about obesity' and what better context to talk about obesity than in respiratory health. The prevalence of obesity is high in many chronic diseases that affect the breathing system, asthma, chronic obstructive pulmonary disease (COPD), obstructive sleep apnoea (OSA), and COVID-19, to name a few. In fact, you could say that obesity and these individual conditions are syndemic. That is, the conditions coexist, interact with each other, produce a larger burden of disease as coexisting conditions than what they cause individually, and have common societal determinants, leading to vulnerability.2, 5 Many diseases of the respiratory system are associated with obesity, which leads to increased complexity for management. In the Australasian Severe Asthma Web-based Database, the prevalence of obesity in severe asthma and non-severe uncontrolled asthma was 49.5% and 26.5%, respectively.6 Obesity is not only a risk-factor for the development of asthma, but also associated with increased severity, more symptoms, poorer quality of life, and increased medication use.7 Losing as little as 5% body weight improves asthma control and quality of life.8 Similarly, obesity is the primary risk-factor for the development of OSA. The Wisconsin Sleep Cohort demonstrated that an increase in BMI of 10% was associated with a 32% increase in the aponea-hypopnoea index (AHI). Although weight loss contributes to an improvement in AHI, the impact is not equivalent. Specifically, a 10% reduction in weight is associated with a 26% decrease in AHI.9 COPD is a condition that is often associated with low body weight; however, obesity is reported in over one third of the COPD of the population.10 An obesity paradox has also been observed in COPD, and current data suggest that a BMI around 30 kg/m2 is associated with the greatest survival, but as weight continues to increase, this effect is lost. These data highlight the need for personalized approaches to weight loss.11 Respiratory infections and obesity are also concerning, with COVID 19 being a leading example. Obesity is associated with an increased risk of severe COVID-19 and higher mortality.12 While these are only a few respiratory conditions that are complicated by obesity they highlight the importance of obesity in the respiratory clinic. It is due to these reasons that obesity has been proposed as a treatable trait in asthma, COPD, OSA, interstitial lung disease (ILD), and COVID-19.13 There are many barriers to effective treatment of obesity. Lack of understanding about the biology of obesity leads to a misperception that a person's lack of weight loss is related solely to their lifestyle or lack of willpower.1 However, treatment success is multifactorial. Barriers are systemic and societal, and include a lack of political action and investment into obesity management, an absence of training for health care professionals involved in obesity care, high costs associated with efficacious treatments, food insecurity, obesogenic environments, obesity not being classified as a chronic disease, and of course stigma associated with obesity.2, 3, 14 Unfortunately, obesity continues to be associated with stigma—and people with obesity are often blamed for their 'self-inflicted lifestyle condition', with language like 'stupid, ugly, unhappy, less competent, sloppy, lazy, and lacking in self-discipline and motivation', used to describe people with obesity. Instead, we should be thinking of obesity as a chronic disease, which requires management, just as any disease does. This weight stigma causes discrimination and halts progress in health promotion.4 Bias experienced by people living with obesity is unfortunately ingrained in healthcare professionals, families, and society.14 Have a look at recent publications investigating obesity among respiratory patients and you will read 'obese subjects, obese asthmatics, obese people', these terms focus on the condition rather than the person. Thinking about the person with obesity allows a more person-centred approach to care. So, how do we rethink this approach? The theme of this year's World Obesity Day provides clues. Let's talk about obesity! If obesity was a pulmonary trait, it would take primacy during clinical consults. Given the major deleterious impacts of obesity on people with respiratory disease, why do we not prioritize this important trait? A qualitative study of healthcare professionals involved in the care of people living with obesity within a tertiary care hospital suggests that clinicians are not comfortable in raising the topic, or they perceive a lack of skills, or familiarity with how to address treatment.14 Now with effective pharmacotherapies available for weight loss, even more we should be thinking about the management of obesity for people with respiratory disease like we do for people who smoke cigarettes. In fact, the behavioural change model of the 5 As (Ask, Assess, Advise, Agree, Assist) has been proposed for use when treating people living with obesity, incorporating appropriate language, effective behavioural, lifestyle, pharmacological and surgical treatments, and referral and follow up as part of a holistic approach.15, 16 Figure 1 gives examples of how this can be used as part of effective consultations. Obesity and respiratory diseases co-exist, worsen outcomes, and share risk-factors. To improve the lives of people living with co-existing obesity and respiratory disease we need to drop the stigma, practice in a person-centred approach, talk about obesity empathetically and respectfully, agree on and implement effective treatment strategies, refer to multidisciplinary healthcare professionals, and review and support patients in their treatment journey. Paola Urroz Guerrero for image design. Open access publishing facilitated by The University of Newcastle, as part of the Wiley - The University of Newcastle agreement via the Council of Australian University Librarians. Vanessa M. McDonald reports speaker and advisory board fees from AstraZeneca, GlaxoSmithKline, Boehringer Ingelheim and grants from AstraZeneca, GlaxoSmithKline, outside the submitted work.