key: cord-0859942-nm3dzxoy authors: Barrera, Emiliano Lopez; Miljkovic, Dragan title: The link between the two epidemics provides an opportunity to remedy obesity while dealing with Covid-19 date: 2022-03-29 journal: J Policy Model DOI: 10.1016/j.jpolmod.2022.03.002 sha: fb39c651dcff9bad13a1da11482e1a109ed1ee7d doc_id: 859942 cord_uid: nm3dzxoy The World Health Organization proclaimed the global epidemic of obesity more than twenty years ago. However, there has never been a coordinated action to address the problem on the global level. Covid-19 virus pandemic is world’s largest public health problem currently. Many comorbidities associated with Covid-19 and obesity mortality are common. We determine that obesity is single largest and most common cause of mortality in Covid-19 patients globally based on a sample of 171 countries, while economic variables have no impact. This creates an opportunity to finally address the obesity global epidemic through an effort coordinated on the global level. Obesity is a complex disease involving an excessive amount of body fat (Mayo Clinic, 2022). The World Health Organization (WHO) described obesity as a global epidemic more than twenty years ago (World Health Organization, 2000) . The problem remains as continuous global increase of obesity did not subside. In 2016, more than 1. Organization, 2020). It has been long hypothesized and confirmed that globalization is a major contributor to spreading of obesity and diet-related chronic diseases globally (e.g., Miljkovic et al., 2015 and 2018; Oberlander et al., 2017) . If we understand globalization as a process by which national/regional economies, societies and cultures have become integrated through a global network of economic, technological, socio-cultural, political and biological factors (Croucher, 2018) , rather than the trade liberalization only, the possibility of its resulting externalities, including increasing rate of obesity, rises significantly . Overweight and obesity are major causes of many comorbidities which can lead to further morbidity and mortality. For example, increased overweight and obesity have been associated with increased death rates for all cancers combined and for cancers at multiple specific sites (Calle et al., 2003) . Furthermore, increasing body mass index (BMI), as a standard measure of obesity in adults, is associated with glucose intolerance, dyslipidemia, hypertension, We empirically test and demonstrate in this paper that higher obesity rates indeed cause an increase in mortality rates in those infected by COVID-19 globally. Moreover, we also demonstrate that, on global level, high obesity rates are the primary cause of higher mortality rates due to COVID-19. This also holds true across all COVID-19 mortality rate quantiles and after controlling for several other comorbidities or exogenous factors. As obesity is a noncontagious disease, it has always been difficult to establish international standards on how to address the problem. Considering findings on causal linkage between obesity and COVID-19 mortality, we propose more wholistic policies to combat global obesity with the goal to decrease comorbidities and mortality rates associated with both obesity and COVID-19. J o u r n a l P r e -p r o o f There are 171 countries in the sample, and they are listed in the Appendix. The definition of and sources for each variable are provided in Table 1 . We use the methods of Directed Acyclic Graphs (DAGs) (Pearl, 1995 (Pearl, , 2000 Two different models are analyzed for the period starting at the beginning of the pandemic through February 01, 2022: first assumes that vaccinated people are those who received at most two shots of the vaccine, while the second includes those who received booster dose as well. Although we considered other variables in the preliminaries of this study (e.g., number of hospital beds, macro-economic variables), their inclusion in the final analysis would be to the detriment of the number of countries that could be examined in the study. In other words, due to the lack of data, there is a trade-off between a more comprehensive approach to the causality of the COVID-19 attributable diseases and a broader examination that could bring most countries into the analysis (which is the scope of the present study). In addition to that, variables such as GDP or number of hospital beds are also indicators of the level of economic development and are highly correlated with but less comprehensive than the HDI. Hence, most comprehensive economic development indicator/variable (HDI) is selected in the model. Figure 1 contains the DAG while the associated statistical results are provided in Table 2 . We now turn to the second model which includes those who received not only two vaccine shots but a booster dose as well. These results remain similar but with one fundamental difference: larger share of the population older than 65 does not cause increase mortality from COVID-19. This has important implications as older population seems to be better protected due to booster shot from COVID-19 and thus less vulnerable. Obesity, however, remains the key direct causal contributor to mortality from COVID-19. The level of economic development as presented by HDI has two important indirect causal impacts on mortality from COVID-19, moving in opposite directions. Just like before, relative affluence leads to increased obesity J o u r n a l P r e -p r o o f 9 levels and, in turn, increased mortality from COVID-19. However, higher HDI also implies larger share of older population and causes more booster vaccines being inoculated. In this case, it seems that the larger affluence level does serve as a protector of older population via high rates of booster shots injected. Figure 2 contains the DAG while the statistical results are provided in Table 3 associated with this model. Results from the DAGs analysis are used in this step to facilitate proper econometric model specification and serve as an indirect test for endogeneity (Miljkovic et al., 2016) . Quantiles have been designated in 10 percentile increments. The results are reported in Table 4 . The results indicate that strong positive relationship between the adult obesity rates and the COVID-19 attributed deaths persists at 10 percent significance level or lower for all but the lowest thirty percentile. Coincidentally, countries with lowest mortality rates are also the countries with lowest prevalence of obesity. An important policy implication of this result is its global nature thus enabling universal policy that could address both obesity and COVID-19 epidemics globally. The results indicate that strong positive relationship between the adult obesity rates and the COVID-19 attributed deaths persists at 10 percent significance level or lower for all but the lowest thirty percentile. An important policy implication of this result is its global nature thus enabling universal policy that could address both obesity and COVID-19 epidemics globally. The relationship between the share of 65 and older population and the COVID-19 attributed mortality rates is equally transparent. It is positive and statistically significant at 5 percent or lower significance level at all but the lowest 20 percentiles only. This result is consistent with the DAGs established in the first model, positive causation between the share of 65 and older population and the COVID-19 mortality rates. Finally, no significant correlations at any percentile but the 90 th are observed between the HDI and mortality rates, and none at all between the vaccination rate or population density and the COVID-19 attributed mortality rates. The robustness of the results is checked by running the analysis for the period from the beginning of the pandemic through August 01, 2021, i.e., the early vaccination stage. We consider people who received at least one dose of a COVID-19 vaccine. The results are qualitatively identical to those of the double vaccinated population on February 01, 2022. The DAGs and associated statistics are presented in Figure 3 and Table 5 , respectively. Table 6 . The results indicate that strong positive relationship between the adult obesity rates and the COVID-19 attributed deaths persists at 5 percent significance level (or better) for all but the lowest twenty percentile. Countries with lowest mortality rates are also the countries with lowest prevalence of obesity. The relationship between the share of 65 and older population and the COVID-19 attributed mortality rates is also strong. It is positive and statistically significant at 10 percent significance level (or better) at all but the lowest and highest 10 percentiles only. This result is consistent with the DAGs established positive causal relationship between the share of 65 and older population and the COVID-19 mortality rates. Finally, no significant correlations at any percentile are observed between the vaccination rate and population density, and the COVID-19 attributed mortality rates. The HDI is negatively correlated, at 10 percent significance level, only at the 60 th percentile with the COVID-19 attributed mortality rates. Hence, direct impact of economic affluence on the mortality due to COVID-19 is all but negligible globally. To further check for the robustness of the above results, same analysis is conducted but on the mortality data through November 30, 2020. Therefore, we consider the period prior to the J o u r n a l P r e -p r o o f beginning of the COVID-19 vaccination worldwide in December of 2020. While we lose the vaccination control variable here, all other data remains the same with the exception of mortality data. In one final robustness check run, we also substitute the GDP per capita for HDI, as an alternative measure of relative affluence or development. DAGs results are presented in Figure 4 and related Tables 7 and 8 Tables 7 and 8 ). HDI has an indirect impact on mortality via both obesity and older age. -0.0136 0.0242 -0.5618 0.5750 *Null hypothesis for T and P is that the parameter is zero. The results of the quantile regression follow and they indicate similar pattern as in the original time-frame: that strong positive relationship between the adult obesity rates and the COVID-19 attributed deaths persists at 1 percent significance level for all but the lowest ten percentile. Countries with lowest mortality rates are also the countries with lowest prevalence of obesity. The relationship between the share of 65 and older population and the COVID-19 attributed mortality rates positive and statistically significant at 10 percent significance level at the 20th, 40 th , 60 th , 70 th and 80 th percentiles only, and not significant at other percentiles. This result is again consistent with the DAGs established positive but statistically weak causal relationship between the share of 65 and older population and the COVID-19 mortality rates. The impact of older population on increased COVID-19 attributed mortality rates is established but is not as obvious as the popular narrative seems to imply. Finally, no significant correlations J o u r n a l P r e -p r o o f at any percentile are observed between the HDI or GDP per capita and population density, and the COVID-19 attributed mortality rates; hence, these results are not included in Table 9 . The implications of globalization are different for different countries and regions. Rich, more developed countries are leading the charge and promote the idea of globalization, which enables them to enlarge the markets for their products and increase the socio-political influence on the rest of the world (Croucher, 2018) . Many positive aspects of globalization are likely to lead to an increase in standard of living in most countries of the world. Yet, there are some unwanted sideeffects of globalization such as the increase in obesity, which is now considered a global epidemic . Likewise, the impact of globalization on spreading of infectious diseases, including COVID-19, is even more easily observed and measured (e.g., regression results indicate that for no sample (quantile) of countries, from those with the lowest to those with the highest mortality rates attributed to COVID-19 does the vaccination rate have any impact on death from COVID-19. Only indirectly vaccination may have an impact on lesser mortality from COVID-19 as there is no direct causal link between the population of 65 and older who received booster shot, and the mortality rate from COVID-19. Obesity, however, remains largest contributor to mortality from COVID-19 in all considered cases. While our results point to obesity as the largest and most persistent contributors to mortality from COVID-19, all global and national public health efforts seem to be directed into intensifying vaccination rate while no efforts are made to address obesity and related comorbidities as at least long-term target variables. In conclusion, comorbidities associated with obesity are same as many attributed to COVID-19 deaths. Most important finding is that obese population is identified as most-at-risk if infected by COVID-19. In turn, this finding underlines the need for centralized long-term strategy and leadership in fighting global obesity as the largest long-lasting global public health issue. J o u r n a l P r e -p r o o f How does globalization affect COVID-19 responses? Overweight, obesity, and mortality from cancer in a prospectively studied cohort of US adults Globalization and Belonging: The Politics of Identity in a Changing World WHO declares COVID-19 a pandemic Globalization and infectious diseases Obesity and mortality of COVID-19. Meta-analysis Potential outcome and directed acyclic graph approaches to causality: Relevance for empirical practice in economics The Danish tax on saturated fat-short run effects on consumption, substitution patterns and consumer prices of fats Advancements in the economics of food security Regression Quantiles Quantile Regression Comorbidity associated with obesity in a large population: The APNA study 20375742#:~:text=Obesity%20is%20a%20complex%20disease,blood%20pressure%20a nd%20certain%20cancers. (Last accessed on Dual Nature and the Human Face of Food (In)Security Estimating dynamics of US demand for major fossil fuels Determinants of obesity in Brazil: the effects of trade liberalization and socio-economic variables Regional obesity determinants in the United States: A model of myopic addictive behavior in food consumption Economic factors affecting the increase in obesity in the United States: Differential response to price Globalisation and obesity Measuring postharvest loss inequality: Method and applications Food politics: How the food industry influences nutrition and health Globalisation and national trends in nutrition and health: A grouped fixed-effects approach to intercountry heterogeneity Causal diagrams for empirical research Causality: Models, Reasoning, and Inference The book of why: the new science of cause and effect A million variables and more: the Fast Greedy Equivalence Search algorithm for learning high-dimensional graphical causal models, with an application to functional magnetic resonance images Globalization and Infectious Diseases: A Review of the Linkages Causal discovery of feedback networks with functional magnetic resonance imaging A linear non-Gaussian acyclic model for causal discovery Preference heterogeneity and habit persistence: The case of breakfast cereal consumption WHO Technical Report Series World Health Organization Habit formation and demand for sugar-sweetened beverages