The world is struggling to fight the novel COVID‐19 pandemic caused by SARS‐CoV‐2 (severe acute respiratory syndrome coronavirus 2), previously known as “2019 novel coronavirus”. Per the World Health Organization (WHO), data converge that the infection fatality rate of COVID‐19 is 0.5‐1.0%; seasonal influenza has a rate of 0.1 In an attempt to identify the risk factors that might aggravate the prognosis of outpatients or hospitalized patients, obesity might be a potential suspect, since it seems to interfere with the presence or worsening of respiratory tract infections (RTIs), a major component of the mortality of COVID‐19.

Obesity is defined as having a body mass index equal to or higher than 30 kg/m² for all populations worldwide, with the exception of China, where according to the World Health Organization obesity is defined as having a BMI equal to or higher than 27.5 kg/m². Obesity rates have almost tripled during the last 40 years, establishing it as an epidemic. Statistics from WHO in 2016, showed that 13% of the world population suffer from obesity (over 650 million subjects in total) and that 39% (more than 1.9 billion subjects) are overweight. In industrialized countries, roughly half of the population is overweight or obese. In USA, the National Health and Nutrition Examination Survey (NHANES) report reported that 34% of inhabitants have obesity.

In the past, from the “Spanish” influenza of 1918 onwards, in all influenza epidemics, including the 2009 Influenza A virus (IAV) H1N1 pandemic, malnutrition and obesity were associated with severe disease, complications, hospitalization, need for treatment in intensive care units (ICU) and mortality. This pattern seems to be replicated with COVID‐19 and the World Obesity Federation has stated that “obesity‐related conditions seem to worsen the effect of COVID‐19; indeed, the Center for Disease Control and Prevention (CDC) reported that subjects with heart disease and diabetes are at higher risk of COVID‐19 complications and that severe obesity (body mass index [BMI] of 40 kg/m²or higher) poses a higher risk for severe illness”.

Many pathophysiological changes occurring with increased adiposity may contribute to poor prognosis of COVID‐19 patients. In the present review, we aimed to search the scientific literature for pathophysiologic pathways that associate obesity and COVID‐19. We discuss published data regarding the association of obesity with the incidence and severity of respiratory tract infections (RTIs), along with RTI caused by COVID‐19, focusing on molecular or hormonal pathways that may be possibly involved and drawing parallels to previous similar outbreaks of RTIs in previous epidemics.

Regards,

Jessica

Managing editor

Pancreatic disorder and therapy.