Pubblicato: 2021-06-08

COVID-19, a syndemic well before a pandemic disease! The role of tobacco smoking

Facoltà di Medicina Veterinaria, Università degli Studi di Teramo
Presidente Società Italiana di Tabaccologia (SITAB)


The term syndemics, another word derived from the ancient Greek language, was introduced for the first time during the ‘90s in the biomedical language by Dr Merrill Singer, an American medical anthropologist, who several years later signed, along with others, a popular editorial on this topic [1].

Indeed, the expression syndemics applies to a number of preexisting or concurrent disease conditions - with special emphasis on chronic, non-communicable illnesses like cardio-circulatory, hypertensive and neoplastic disorders - as well as to a variety of socio-economic (demographic density and distribution, educational, poverty and hygiene levels, social promiscuity, etc.), climatological-environmental (climate change, global warming, desertification, deforestation, use of land for agricultural purposes, etc.) and lifestyle (cigarette smoking/tobacco consumption, sedentary lifestyle, alimentary habits like eating foods of animal origin from wet markets as it commonly occurs among Chinese people, etc.) parameters/variables, which should be taken into adequate account when analyzing and evaluating the data, numbers and trends of any infectious disease condition. This is particularly true when dealing with globally distributed infections like the SARS-CoV-2/COVID-19 pandemic, the numbers of which at the end of 2020 have exceeded 80 million cases, with 1,800,000 deaths worldwide.

Such an “holistic” vision of pandemics by Merrill Singer, which is well summarized by the term syndemics, has been also the focus of a recent article by Dr Richard Horton, the Chief Editor of The Lancet, in an editorial titled COVID-19 is not a pandemic [2]. This paper was mainly aimed at underlying the mutual interactions occurring, at a global level, among each living creature and not just within mankind, with this additionally representing the explanatory key for life on Earth as well as for the origin and spread of the SARS-CoV-2 pandemic. Based upon the above, Dr Horton invites us to look at this global crisis “not merely as an infectious disease”, since “COVID-19 is not Black Death” but, instead, “a disease killing (mostly) disadvantaged and fragile people”. And, Richard Horton concludes, “without identifying and without intervening on the cofactors making SARS-CoV-2 a lethal virus, no measure will be truly effective. Not even vaccines”.

In this respect, and just to make some examples aimed at providing a clear-cut perception of the COVID-19-associated/related syndemic dimension, we could mention the many and serious hurdles frequently met by patients affected by preexisting illnesses, such as cardiovascular and tumour disease conditions, in getting proper access to health care and assistance as well as to their respective therapeutic regimens. Beside ranking among the most common causes of death in the Western world, cardiovascular and neoplastic disorders show a much higher prevalence in older people, who also represent the population segment more commonly affected by the most severe COVID-19 clinico-pathological disease phenotypes. And, as it is also well known, cardiopathic, hypertensive and neoplastic patients, with special reference to male subjects, are more prone to develop particularly impacting COVID-19 forms, with the heaviest death toll regarding just these individuals [3].

Said in other words, these patients appear to be the victims of a paradox, provided their preexisting disease conditions, which render them more “fragile” towards the most severe clinico-pathological forms of COVID-19, will not benefit in many cases from a level of health care and assistance comparable to the one the same individuals received in the pre-COVID-19 era!

Therefore, in view of a syndemic perspective of the current COVID-19 pandemic, it would be more appropriate to deal with lethality and/or morbidity rates taking into adequate account the relationships existing between SARS-CoV-2 infection and concurrent disease, environmental, social and behavioural conditions. Indeed, the latter ones would generate a sort of vicious circle, thereby enhancing viral spread and pathogenicity.

More in detail, individual behaviours and lifestyles may affect the health status, thus promoting the development of disease conditions like diabetes, Chronic Obstructive Pulmonary Disease (COPD), cardiovascular disorders and tumours, both pulmonary and extra-pulmonary, with all the aforementioned - as well as other simultaneously occurring – illnesses serving as an ideal pabulum increasing SARS-CoV-2 infection’s virulence and pathogenicity [3]. In this respect, most of COVID-19-associated comorbidities, with special emphasis on those characterized by a more severe prognosis [4], would mainly affect male and elderly patients [5], a population segment particularly represented in Italy, which ranks among the first Countries worldwide for longevity- and life expectancy-related parameters [3]. All of these pathologic affections and, especially, chronic cardio-respiratory, dysmetabolic and neoplastic disorders, which are known to increase the risk of developing severe COVID-19 forms [3], mostly result from incorrect lifestyles and habits. Within this framework, a relevant common denominator is represented by smoking, with an estimated over 1,300,000,000 smokers living on Earth [6] and with smoke-related deaths exceeding 7 millions each year [7,8].

The syndemic perspective of COVID-19 is clearly shown also by a number of socio-economic and climatological-environmental variables.

As a matter of fact, clusters of severe SARS-CoV-2 infection cases have been reported in geographical areas characterized by a high population density and by low economic income and educational level, as well as by social promiscuity and/or lack of hygiene and respect of viral spread mitigation measures (as it happens, for example, among the Afro-Americans living in USA, who are also very used to smoking).

Furthermore, the progressive increase in the mean temperatures throughout the last 140 years (especially for the 6 years period 2015-2020, with 2020 being the hottest year ever recorded on Earth), accompanied by enhanced desertification and deforestation - the latter originating also from the dramatic fires occurred in many geographical areas of the Planet in the recent past -, together with the alarming land loss due to intensive agriculture, would act synergistically in multiplying the chances of mutual interaction(s) between us and domestic animals, on one side, and wild animal species, on the other. As in the well-documented cases of bats and rodents, wild animals may serve, in fact, as reservoirs for a large number of infectious pathogens, thereby making possible - under the influence of the conditions cited above - the spillover of these agents from wildlife to humans. We should firmely keep in mind, within such context, that no less than 70% of the pathogens - both viral and non-viral - responsible for the so-called emerging infectious diseases have either a documented or suspect origin from a primary wild animal host [9]. This seems to apply also to SARS-CoV-2 as well as, with certainty, to its two betacoronavirus predecessors, namely SARS-CoV and MERS-CoV.

Based upon the above, an “holistic” approach efficiently summarized by the One Health concept, reciprocally and tightly linking human, animal and environmental health, would represent the winning solution and formula to be adopted in order to adequately tackle and foresee - with the strategic aid of “artificial intelligence, most hopefully - all the future epidemics and pandemics.

As a consequence, this would also render the use of the term and adjective syndemic more appropriate than pandemic when dealing with similar global emergencies.


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  2. Horton R. Offline: COVID-19 is not a pandemic. Lancet. 2020; 396:874. DOI
  3. Albini A, Di Guardo G, Noonan DM, Lombardo M. The SARS-CoV-2 receptor, ACE-2, is expressed on many different cell types: implications for ACE-inhibitor- and angiotensin II receptor blocker-based cardiovascular therapies. Intern Emerg Med. 2020; 15:759-66. DOI
  4. Yang H, Yang LC, Zhang RT, Ling YP, Ge QG. Risks factors for death among COVID-19 patients combined with hypertension, coronary heart disease or diabetes. Beijing Da Xue Xue Bao Yi Xue Ban. 2020; 52:420-4. DOI
  5. Zagà V, Gallus S, Gorini G, Cattaruzza MS. Perché il coronavirus è più mortale tra gli uomini che tra le donne. L’ipotesi tabagismo. Why coronavirus is more deadly among men than among women? A smoking hypothesis. Tabaccologia. 2020; 18:21-9.
  6. Zagà V, Gorini G, Amram DL, Gallus S, Cattaruzza MS. Epidemia o pandemia da tabacco? Tobacco epidemic or tobacco pandemic?. Tabaccologia. 2020; 18:2-3.
  7. Cattaruzza MS, Zagà V, Gallus S, D’Argenio P, Gorini G. Tobacco smoking and COVID-19 pandemic: old and new issues. A summary of the evidence from the scientific literature. Acta Biomed. 2020; 91:106-12. DOI
  8. Østbye T, Taylor DH, Jung SH. A longitudinal study of the effects of tobacco smoking and other modifiable risk factors on ill health in middle-aged and old americans: results from the Health and Retirement Study and asset and health dynamics among the oldest old survey. Prev Med. 2002; 34:334-45. DOI
  9. Casalone C, Di Guardo G. COVID-19 and mad cow disease: so different yet so similar. Science. 2020. Publisher Full Text


Giovanni Di Guardo

Facoltà di Medicina Veterinaria, Università degli Studi di Teramo

Vincenzo Zagà

Presidente Società Italiana di Tabaccologia (SITAB)


© Sintex Servizi S.r.l. , 2021

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