Is obesity the missing link between COVID-19 severity and air pollution?

Abstract

In the previous publication “Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?” Conticini et al. hypothesized that the surplus of lethality of the novel SARS-CoV-2 in Northern Italy may be at least in part explained by the evidence of highest pollution reported in this area, as both severe COVID-19 and smog exposure are correlated to an innate immune system hyper-activation with subsequent lung inflammation and injury. Since this hypothesis alone does not fully explain why specific subgroups of patients are at major risk, we hypothesized that obesity may be one of the links between COVID-19 severity and high level of air pollution. First, obesity is a predisposing factor for SARS-Cov-2 infection and worse COVID-19 outcomes, and unequivocal evidence demonstrated that fat mass excess is independently associated with several pulmonary diseases and lung inflammation. Moreover, it has been shown that obesity may intensify the detrimental effects of air pollution on the lungs, and this is not surprising if we consider that these conditions share an excessive activation of the immune system and a lung inflammatory infiltrate. Finally, fat mass excess has also been speculated to be itself a consequence of air pollutants exposure, which has been proved to induce metabolic disruption and weight gain in murine models. In conclusion, although many variables must be taken into account in the analysis of the pandemic, our observations suggest that obesity may act as effect modifier of smog-induced lung-injury, and the concomitant presence of these two factors could better explain the higher virulence, faster spread and greater mortality of SARS-CoV-2 in Northern Italy compared to the rest of the country.

The main factors influencing COVID-19 spread and deaths in Mexico: A comparison between phases I and II

“…In Phase I ( Phase II ), an increase in 1 metric ton in PM2.5 (log) per year would increase the COVID-19 death rate by a factor of 1.25 ( 1.96 ). The finding agrees with relevant studies tackling the atmospheric determinants of population’s vulnerability to COVID-19 in the U.S. ( Bashir et al, 2020 ; Wu et al, 2020 ), Italy ( Lubrano et al, 2020 ), China ( Lin et al, 2020a ), and some Latin American cities ( Bolaño et al, 2020 ). All of them unanimously confirmed the correlation between atmospheric conditions and COVID-19 cases, making poor air quality an additional co-determinant of COVID-19 lethality.…”

“…In the context of Mexico, our results at the municipal-level indicate that, regardless of lockdown policies, metabolic disorders, such as obesity or diabetes, can exacerbate infections and deaths. Our findings agree with the findings of Lubrano et al (2020) , who demonstrated that the extremely high level of COVID-19 lethality in Northern Italy, compared to the rest of the country, can be explained by differences in air pollution and obesity. Sanchis-Gomar et al (2020) also supported the above-mentioned link between obesity/air pollution and higher COVID-19 lethality.…”

“…Interestingly, there studies pointing to significant positive association between air pollution and lethality rates. This has been explained by the contribution of air pollution to respiratory tract infections, pulmonary disease, or diabetes burden ( Lubrano et al, 2020 ; Ma et al, 2020 ). With vastly different climates among its states and municipalities, Mexico has displayed differentiated effects on confirmed COVID-19 cases ( Méndez-Arriaga, 2020 ).…”

The main factors influencing COVID-19 spread and deaths in Mexico: A comparison between Phases I and II

“…Similarly, an enormous amount of scientific literature has provided strong evidence that climate factors such as high air temperature or exposure to air pollution lead to an increase of lethality rates (Lin et al, 2020a,b; Ahmadi et al, 2020; Bashir et al, 2020; Riccò et al, 2020; Sobral et al, 2020). This has been explained by the contribution of air pollution to respiratory tract infections, pulmonary disease, or diabetes burden (Lubrano et al, 2020; Ma et al, 2020; Xu et al, 2020). Mexico, with vastly different climates among its states and municipalities, has presented differentiated effects on COVID-19 confirmed cases (Méndez-Arriaga, 2020).…”

Common factors of COVID-19 cases and deaths among the most affected 50 countries

“…PM 2.5 ), climatic (i.e. temperature and humidity), and socio-economic inequality – all of these factors are widely documented [ [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] ]. Understandably, most of the confirmed cases are based on test results against symptomatic cases and asymptomatic cases are generally undocumented.…”