A Complex Interplay: Navigating the Crossroads of Tobacco Use, Cardiovascular Disease, and the COVID-19 Pandemic: A WHF Policy Brief

Pandemic response and mental health

The COVID-19 pandemic compelled countries to enforce strict sanitation regimes and social distancing measures, including lockdowns. These interventions, alongside fears surrounding SARS-CoV-2 infection, generated large amounts of stress in the population. As a result, the mental health of society as a whole has been severely affected by the global epidemic, to the extent that the term “COVID depression” was coined [21]. In fact, the pandemic has led to a substantial increase in the number of people showing signs of depression and cases of suicides worldwide [22].

According to a survey conducted by the United Nations, the percentage of people who felt distress during the COVID-19 pandemic rose to 35% in China, 45% in the United States, and 60% in Iran [23]. In addition, a Centers for Disease Control and Prevention online survey of 5,412 US adults, conducted in June 2020, found that 40.9% of respondents reported experiencing some form of mental disorder, such as symptoms of anxiety or depressive disorders. Of these respondents, 10.7% indicated that they had seriously contemplated suicide in the past 30 days [24]. In Japan, suicide rates increased for 4 consecutive months from July 2020. In particular, October 2020 reported a staggering 39.9% increase from the previous year, with an alarming 82.6% increase among women, in particular [25]. In general, prolonged curfews following major natural disasters are known to have significant negative impacts on people’s psyche, as exemplified by the surge in incidence of mental illness following lockdown measures [26]. The above findings suggest that individuals may be prone to poor and/or irrational decision-making under high-stress circumstances, such as a declared state of emergency [27].

Mental health issues often coincide with the initiation, continuation, and escalation in use of addictive substances (e.g., tobacco, alcohol, drugs, etc.) as well as with negative changes in diet and physical activity; this raises concerns about potential harmful downstream effects, such as an increase in noncommunicable diseases and specifically, cardiovascular disease [28].

Pandemic response and tobacco consumption

The COVID-19 pandemic has had a noticeable influence on smoking behaviours. Factors such as stress and poor mental health are known to increase smoking frequency, quantity and dependence, as well as trigger relapses in ex-smokers [29]. While some countries have reported an increase in cigarette consumption, others have observed varied usage patterns at the population level [30].

A study in the United Kingdom involving current smokers (n = 329) reported that 25.2% smoked more cigarettes than usual, 50.9% smoked the same amount and 20.2% smoked less. The study also found significantly worse mental health, anxiety, stress and depressed mood among those who smoked more, suggesting a pandemic-induced deterioration in mental health and psychosocial well-being, as well as an associated increase in smoking [31]. In a sample of individuals in the US from vulnerable populations (i.e., those with lower-socioeconomic status or with psychiatric conditions, N = 332) current smokers reported smoking more cigarettes during the pandemic compared to the pre-pandemic period, even leaving their homes specifically to purchase cigarettes [32]. In Japan, among current smokers (n = 1,000), 18% smoked more cigarettes than usual, 69.6% smoked the same amount and 11.4% smoked less [33]. Elevated stress due to changes in daily life as well as the social environment was reported as the primary cause of the shift in consumption pattern.

A number of studies have reported no significant change in the total number of cigarettes smoked, as increases in some demographics may have been offset by decreases in others. In fact, it is plausible that disadvantaged populations (e.g., those with mental health disorders, etc.) either continued to smoke or smoked more, while more advantaged groups seized the opportunity to quit tobacco. Those who smoked less were often motivated by a desire to mitigate the risk of severe COVID-19 illness and to protect family members from second-hand smoke [34, 35, 36].

Access to health services during the COVID-19 pandemic: delayed diagnosis and treatment of acute and chronic NCD conditions

During the COVID-19 pandemic, and particularly during the first waves, access to healthcare facilities was severely disrupted. Tobacco use is a risk factor for many of the acute and chronic conditions that are exacerbated by poor access to the healthcare system, with special implications for vulnerable populations (e.g., homeless, migrants, etc). According to the WHO Pulse Survey on the Continuity of Essential Health Services During the COVID-19 Pandemic, disruptions of essential health services were reported by 90% of countries. These included services for communicable diseases, noncommunicable diseases (with a 69% reduction in diagnosis and treatment), mental health and nutrition, as well as reproductive, maternal, newborn, child and adolescent health. Significant reductions in outpatient care attendance were reported by 76% of countries and potentially life-saving emergency services were disrupted in almost a quarter of countries. These disruptions were caused by a combination of demand- and supply-side factors, with 76% of the countries reporting a lower demand in outpatient care attendance due to lockdowns (48%) or financial difficulties (33%). Cancellation of elective services was the most commonly reported issue on the supply side (66%), in addition to staff redistribution to provide COVID-19 care, lack of sufficient personal protective equipment for healthcare professionals, closures of services or healthcare facilities, and interruption of supplies for health products [37].

During the first waves, most hospitals were overwhelmed by acute COVID-19 admissions, and primary care nearly collapsed in some countries. Many healthcare professionals were infected or diverted from their usual activities to provide COVID-19 related care. As a result, the scarcity in human resources had become a major barrier to dealing with the health crisis. For instance, preventive activities, such as smoking cessation programmes, were interrupted for several months. Many surgical services, notably cancer surgeries, were also cancelled or delayed. In addition, the follow-ups of many chronic conditions were interrupted, which led to severe consequences in terms of health outcomes [38].

During the lockdowns, a significant decline in hospitalisations for cardiovascular events was recorded in many countries. Different studies have reported a drop in the number of patients admitted for acute coronary syndromes (ACS) as well as a reduction in the number of cardiac catheterisations [39, 40, 41, 42]. A retrospective analysis of consecutive patients admitted for ACS performed in 15 hospitals from northern Italy with primary percutaneous coronary intervention programmes during the first months of the pandemic, showed a decline in ACS admissions compared to the same period the previous year (i.e., 13.3 admissions per day versus 18.0, incidence rate ratio, 0.74; 95% confidence interval [CI], 0.66 to 0.82; P < 0.001). In addition, a further reduction in ACS admissions was reported after the national lockdown [40]. Even though the exact reasons for such a decrease are difficult to determine, it has been reported that some patients avoided seeking medical attention during the first months of the pandemic due to fear of contagion. Social distancing and avoidance of medical care are potential behavioural explanations, as has been reported in previous pandemics [43]. In a multicentre retrospective observational registry conducted in 75 specific ACS care centres in Spain, comparing patients treated before and after COVID-19, the number of suspected ST-elevation myocardial infarction (STEMI) patients treated decreased by 27.6% after the COVID-19 outbreak, as the number of confirmed STEMI fell by 22.7%. In addition, there were no changes in reperfusion strategy or time from first medical contact to reperfusion, despite patients presenting longer ischaemic times (233 vs 200 minutes, p < 0.001). The belated consultations of health services were presumably the main cause of delay to reperfusion. It is worth noting that early management of acute STEMI is crucial in reducing cardiovascular morbidity and mortality. In fact, in the Spanish study, in-hospital mortality was significantly higher during COVID-19 (7.5% vs 5.1%; unadjusted OR, 1.50; 95%CI, 1.07–2.11; P <.001) [42]. Evidence from the United Kingdom suggests that return to pre-pandemic levels of cardiovascular disease care activity for numerous procedures has been slow [39].

Secondary prevention was also severely impacted. Access to cardiac rehabilitation and structured secondary prevention programmes was compromised, undermining the recent progress in delivering secondary prevention. In a cross-sectional study with a survey completed by 1,062 cardiac rehabilitation programmes across 70 countries, 75% reported ceasing temporarily their activity or interrupting the admission of new patients [44]. Additionally, many cardiac rehabilitation centres, especially those that served rural and socially vulnerable populations, closed permanently due to interruptions in payments for preventive services [45]. Smoking cessation is an important goal in secondary prevention and a core component of cardiac rehabilitation; thus, cessation efforts were further stymied by these closures. The interruption of smoking cessation programmes, coupled with the stressful social and economic conditions of the pandemic, have been a barrier to advancing tobacco cessation efforts.

Interruption of smoking cessation services

The COVID-19 pandemic emphasised the importance of preserving respiratory as well as cardiovascular health, providing a unique window of opportunity to further promote tobacco cessation and control. Unfortunately, excessive pressure on healthcare systems resulted in drastic interruptions to smoking cessation services.

A cross-sectional US study analysing the cessation behaviour of adults aged 18 years and above reported that, for the first time in a decade, the annual past-year quit attempt prevalence decreased (i.e., from 65.2% in 2019 to 63.2% in 2020), with the largest relative decreases being among individuals aged 45 to 64 years, individuals with 2 or more comorbidities, Black individuals, individuals with lower educational attainment, and women. Concurrently, retail sales of nicotine replacement therapies across 31 US states decreased by an average of 1% to 13% compared to expected sales. Possible explanations for this decrease include healthcare disruptions and pandemic-induced stress [46].

In response to the challenges imposed by the pandemic, many healthcare systems have established or strengthened digital health solutions to facilitate access to health professionals and counterbalance limited access to healthcare facilities. In particular, telemedicine has been especially well-integrated into our post-COVID practices. Telehealth can play a crucial role in providing advice and monitoring smoking cessation attempts. It can also facilitate access to smoking cessation interventions for socially disadvantaged populations or individuals living in remote areas. The promotion of tobacco cessation through apps and digital public health campaigns can play a key role in reducing the burden of tobacco in the post-COVID-19 era. According to recent studies, many smokers expressed interest in accessing various forms of cessation assistance during the pandemic [47].

Indeed, the COVID-19 pandemic presumably also provided smokers with additional incentives and motivation to quit tobacco. In fact, a recent study reported a positive effect of the pandemic on smoking cessation rates in patients attending a specialised clinic in Turkey, with successful cessation rates raising from 23% to 31% during the pandemic [48].

Health authorities and regulators worldwide need to provide a synergistic response to the intertwined public health issues of COVID-19 and the tobacco epidemic. Effective smoking cessation programmes, telemedicine tools, and smoking cessation campaigns will play a key role in the post-COVID era.

The case for sustaining NCD and tobacco cessation services through health emergencies

COVID-19 is one the most devastating pandemics in human history, disproportionately affecting those with co-morbid diseases [5, 49]. Data suggest that smokers infected with COVID-19 are at greater risks of longer hospital stays, ICU admission and need for mechanical ventilation [5, 49, 50, 51]. In fact, several studies have corroborated that patients with COVID-19 who are former or current smokers face significantly higher mortality rates in comparison to never smokers [5, 49, 50, 51, 52, 53, 54, 55, 56]. In addition, smoking was also identified as a risk factor for increased mortality among COVID-19 patients with underlying chronic health conditions, such as obesity, cancer, chronic obstructive pulmonary disease and cardiovascular disease [5, 49, 57, 58, 59]. Some studies also illustrated that COVID-19-associated mortality among smokers may vary based on sex, with female smokers exhibiting higher mortality rates than male smokers [56].

Although some reports suggested that smoking was not significantly associated with mortality among patients with COVID-19 [60], various meta-analysis collectively demonstrated that mortality rates are statistically higher among current and/or former smokers affected by COVID-19 [5, 57]. It should be evident that smoking remains a risk factor for increased disease severity, morbidity and mortality. As such, comprehensive preventive and treatment services should be fully utilised to lessen the burden of tobacco and COVID-19, especially among vulnerable patients [5, 57].

Biological evidence and plausibility

Biologically plausible pathways suggest that tobacco use could potentially increase susceptibility to, and severity of, COVID-19. Longstanding evidence indicates that smokers, especially current ones, are more susceptible to viral and bacterial respiratory infections, both in mild and more severe forms [61]. Cigarette smoking aggravates respiratory infections, leading to an increased risk of susceptibility to, and severity of, pathogens such as influenza and tuberculosis [62, 63]. The mechanisms connecting cigarette smoking and respiratory illnesses include both immune suppression and physiological changes, such as abnormal cilia function [64]. In addition, many of the harmful chemicals present in tobacco products, along with those generated during aerosolisation through heating or combustion, have deleterious effects on the respiratory system, thereby potentially increasing both susceptibility to and severity of SARS-CoV-2 [65]. Conversely, evidence suggests that the immune system starts to recover and reduces vulnerability to infections within just one month of quitting tobacco [66, 67].

Epidemiologic evidence from prior coronavirus outbreaks

Epidemiological studies of prior coronavirus outbreaks, specifically SARS-1 and MERS, found no evidence to support the hypothesis that smoking offers protection against coronaviruses. In fact, the prevailing body of research suggests that smoking contributes to both a greater risk of illness onset and increased severity. Despite rumours that emerged in 2003 suggesting that smokers were less likely to contract SARS-CoV-1, subsequent studies demonstrated no difference between smokers and nonsmokers in their risks of developing the illness [68]. In addition, studies of another coronavirus strain, the Middle East Respiratory Syndrome (MERS-CoV), revealed that smoking significantly increased the probability of contracting the illness [69]. Additionally, it was found that the case fatality rate among smokers was twice that of non-smokers [70].

Limitations of clinical records and case series designs

Research exploring the relationships between tobacco use and SARS-CoV-2 have primarily relied on clinical data from hospitals and other healthcare settings. Even before the COVID-19 pandemic, multiple studies highlighted significant concerns and gaps regarding accurate documentation of tobacco use in clinical records. For instance, a Finnish study found that only 60% of patients admitted to hospital between 2010 and 2016 had tobacco use documented in their clinical records. Furthermore, the likelihood of tobacco use being documented varied based on the patients’ illness and disease diagnoses [3].

The COVID-19 pandemic, which overwhelmed many health systems, likely made the collection of accurate clinical data on tobacco use even more challenging for clinicians and other health personnel. For example, a review found that 80% (186 out of 233) of studies published between February and August 2020 had ‘poor’ documentation, with more than 20% of clinical records lacking information on tobacco use status [71]. These incomplete or inaccurate clinical records pose substantial methodological issues for studying the relationships between tobacco use and COVID-19.

Another methodological concern is the predominant use of, and reliance on, ‘case series’ medical research designs in the majority of published studies on smoking and COVID-19. These studies draw from a pool of subjects engaged in clinical care, without the potential for control or comparison groups. While much of the research regarding smoking and COVID-19 relies on individuals who are actively engaged in clinical settings, researchers have pointed out that smokers participating in these clinical studies may not be representative of the general population. For instance, Simons and colleagues suggest that uninfected smokers may be overrepresented in SARS-CoV-2 testing data because they are more likely to present with COVID symptoms (e.g., coughing, altered sense of smell or taste, etc.) that meet community criteria for testing [71].

The potential underreporting of current smoking is evident across many studies using clinical data. For example, out of 74,439 case report forms of patients with COVID-19 submitted to the US Centers for Disease Control and Prevention during the early phase of the pandemic, only 1.3% of patients were classified as current smokers, far lower than what would be expected from the general population [72]. Studies like this do not provide a clear understanding of the association between smoking and COVID-19. Without study designs that better ensure accurate documentation of tobacco use in clinical records and better represent the general population, it will be challenging to determine the extent to which smoking is a prognostic factor for SARS-CoV-2.

Is smoking protective against SARS-CoV-2 infection?

Despite substantial methodological issues, as outlined above, several studies published in the early stages of the pandemic suggested that smoking decreased the risk of infection from SARSCoV-2 [73]. Pro-tobacco constituents amplified these findings, with the media seemingly eager to highlight these potentially counter-intuitive preliminary findings [74].

A rigorous review of the studies that were published from the start of the pandemic through August 2021 found inconsistent and contradictory results with regard to the relationship between smoking and SARS-CoV-2 infection [65]. The review identified 26 studies suggesting that cigarette smoking was associated with reduced SARS-CoV-2 infection rates. However, it also identified 20 studies associating smoking with increased SARS-CoV-2 infection rates, as well as 7 studies that found no association between smoking and SARS-CoV-2 infection. Despite presenting inconsistent results pertaining to infection, the review provided clear evidence that smokers were more likely to experience more severe disease outcomes.

While additional research is required to fully understand the exact relationship between smoking and infection from SARS-CoV-2, it has been well-documented that smoking is a major risk factor for the incidence of respiratory infection, including other coronaviruses such as MERS, as well as for the severity of disease progression [75, 76].

Tobacco and long COVID

Most patients afflicted by COVID-19 will experience symptoms relief within 2–6 weeks. However, in some cases, after recovery from initial infection, various symptoms may persist for 2–3 months, or even longer, as sequelae. These lingering symptoms, often referred to as long COVID, can occur irrespective of age and severity of COVID-19.

Symptoms of long COVID can be diverse, including fatigue, arthralgia, muscle pain, cough, phlegm, shortness of breath, chest pain, hair loss, memory impairment, poor concentration, insomnia, headache, depression, olfactory disturbance, dysgeusia (i.e., taste disorder), palpitations, diarrhoea, abdominal pain, sleep disturbance, and muscle weakness. Although precise data are not yet available, as diagnostic criteria and methods of investigation vary from country to country, it is estimated that 10–20% of patients experience long COVID [77]. Approximately two-thirds of these sequelae will disappear within three months, but in some cases, recovery may extend to years. Concerningly, long COVID has been associated with significant psychiatric issues, including suicidal ideation and behaviour [78].

Various theories have been posited regarding the pathogenic mechanisms of long COVID, including direct damage to virus-infected tissues (especially the lungs), progressive and continued inflammation due to immune dysregulation, vascular damage and tissue ischaemia caused by increased blood coagulation and subsequent thrombus formation, dysregulation of the renin-angiotensin system caused by viral infection, and post-intensive care syndrome in critically ill patients [79].

Notably, smoking and e-cigarettes, apart from being independent risk factors for more severe clinical manifestations and worsening of COVID-19, also contribute to the development of long COVID. These correlations have been reported in several large cohort studies [80, 81, 82]. The risk of sequelae in smokers is reported to be 8.39 times higher than in individuals who never smoked [83]. Furthermore, smoking has also been identified as an independent risk factor for delayed recovery from long COVID [84]. Therefore, implementing tobacco control measures is critical in preventing and managing long COVID effectively.

Tobacco use and risk of severe COVID-19

Risk factors for severe COVID-19 outcomes include smoking, advanced age and pre-existing conditions, such as cardiovascular disease, diabetes, malignant neoplasms and chronic respiratory disease. A multivariate study from China identified four key factors contributing to COVID-19 severity: a history of smoking, temperature upon admission, respiratory failure and age 60 years or older [85]. Of these, the odds ratio associated with smoking history was the largest at 14 (confidence interval [1.6–45]; p = 0.018), surpassing the odds ratios for the other aggravating factors (8.5–9.0). Reports on 1,099 infected individuals in China indicate that 12.4% of current smokers and 23.8% of former smokers experienced severe outcomes, including admission to intensive care units, ventilator use, or death. In contrast, only 4.7% of nonsmokers experienced similar outcomes [75]. Furthermore, the proportion of patients with severe outcomes was 21.2% for current smokers and 42.9% for past smokers, both higher than the 14.5% for nonsmokers [75]. The increased severity of COVID-19 symptoms in former smokers could be explained by the fact that they may have been, on average, older than current smokers. Another possibility would be that past smokers may have more comorbidities and, consequently, an increased risk of serious illness compared to current smokers (e.g., quitting tobacco after contracting a disease, etc).

As noted above, smoking is an important determinant of COVID-19 severity. It is important to highlight that most underlying diseases associated with severe COVID-19 outcomes, such as cardiovascular disease, chronic obstructive pulmonary disease and diabetes mellitus, are all strongly associated with tobacco use.

Tobacco control opportunities and missed opportunities

The pandemic has created a unique set of challenges and opportunities for tobacco control efforts. It has spotlighted the importance of preserving respiratory and cardiovascular health, highlighting the urgency of promoting smoking cessation and minimising tobacco use.

As restrictions eased, some countries implemented measures to protect their populations against exposure to second-hand smoke. For instance, in some cases, policies were implemented to prohibit smoking in outdoor areas of bars and restaurants, with customers required to smoke at a designated distance. Unfortunately, these protective measures were often withdrawn as the de-escalation of restrictions progressed.

The pandemic has also disrupted ongoing smoking cessation programs, leading to missed opportunities to further alleviate both the burden of COVID-19 and tobacco-related diseases. With healthcare systems overwhelmed by the influx of COVID-19 cases, many healthcare professionals were diverted from their usual responsibilities to manage the pandemic, leaving other health services, such as smoking cessation interventions, neglected [38]. However, these obstacles also spurred the development of innovative strategies, including digital solutions such as telemedicine, public health campaigns, and smoking cessation apps, to provide support for individuals trying to quit smoking [46]. Telemedicine and smoking cessation apps can play key roles in providing critical advice and support to individuals trying to quit, especially for those in remote areas or vulnerable populations.

Tobacco control and lessons learnt from the COVID-19 pandemic

The correlation between tobacco use and increased severity of, and mortality from, COVID-19 among hospitalised patients highlights an urgent need for countries to accelerate the implementation of the WHO Framework Convention on Tobacco Control (FCTC) [93]. In fact, the implementation of the WHO FCTC would reduce fatalities from tobacco, COVID-19 and potential future pandemics as many articles within the treaty are highly relevant in the context of the COVID-19 pandemic. For instance, Article 5.3 addresses interference from the tobacco industry, Article 8 protects nonsmokers from second-hand exposure, Article 6 outlines taxation measures which could serve to raise income for national pandemic responses, and Article 14 promotes tobacco cessation [93, 94, 95].

Many countries have demonstrated both the capacity and political will to enact key tobacco control measure throughout the pandemic. For instance, Spain temporarily expanded its smoke-free policies to include outdoor areas [93]. This political resolve was formalised with the quasi-unanimous adoption of a Declaration on WHO FCTC and Recovery from the COVID-19 Pandemic at the Ninth Session of the Conference of the Parties to the WHO FCTC in 2021 [4]. Nevertheless, it is essential that countries maintain and extend these measures beyond the COVID-19 crisis [96].

Furthermore, the pandemic has also exacerbated the health equity and equality issues associated with tobacco use [94, 97]. Studies indicate that the social determinants of health, particularly education, significantly impact both tobacco consumption as well as cardiovascular disease morbidity and mortality. In fact, disadvantaged groups, such as populations with lower socio-economic status and health literacy, are more susceptible to developing cardiovascular disease [98, 99] and more prone to using tobacco products [100, 101]. In the context of the COVID-19 pandemic, families under financial strain and household with lower levels of education experienced worse living conditions (e.g., poor housing, increased exposure to tobacco smoke, etc.) and displayed detrimental health-related behaviour (e.g., physical inactivity, unhealthy diets, etc.) during lockdowns [97]. Therefore, pandemic preparedness and response plans must consider health equity and the social determinants of health.

Case study of India

In India, tobacco-related deaths account for 9.5% of all deaths at the country level, with 48% of these deaths caused by cardiovascular disease, most commonly due to ischaemic heart disease [102]. Furthermore, tobacco use is responsible for the development of cardiovascular disease among younger people, accounting for 26% of CVD cases in the age group of 30–44 years [102]. Studies indicate that smokeless tobacco (ST) use is also a risk factor for cardiovascular disease [103]. According to the INTERHEART study estimates, over 6 million disability-adjusted life years (DALYs) and 258,006 lives lost due to ischaemic heart disease can be attributed to ST use in 2017 [103].