COVID‐19 and tobacco products use among US adults, 2021 National Health Interview Survey

Abstract Background Smoking and vaping are linked to lung inflammation and lowered immune response. Objective Examine the prevalence of coronavirus disease 2019 (COVID‐19) cases, testing, symptoms, and vaccine uptake, and associations with tobacco product use. Methods Data came from the 2021 National Health Interview Survey. The 2021 Sample Adult component included 29,482 participants with a response rate of 50.9%. We investigated COVID‐19‐related outcomes by tobacco product use status and reported national estimates. Multivariable regression models were performed accounting for demographics (e.g., age, sex, poverty level), serious psychological distress, disability, and chronic health conditions. Results In our regression analyses, odds of self‐reported COVID‐19 infection were significantly lower for combustible tobacco product users (vs. nonusers; adjusted odds ratio [AOR = 0.73; 95% confidence interval [CI] = 0.62–0.85]). Combustible tobacco users also were less likely to report ever testing for COVID‐19 (AOR = 0.88; 95% CI = 0.79–0.98), ever testing positive for COVID‐19 (AOR = 0.66; 95% CI = 0.56–0.77), and ever receiving COVID‐19 vaccine (AOR = 0.58; 95% CI = 0.51–0.66) compared with their nonuser peers. Compared to nonusers, users of any type of tobacco who contracted COVID‐19 had higher odds of losing smell (AOR = 1.36; 95%CI = 1.04–1.77), which was more pronounced among exclusive e‐cigarette users. The odds of receiving vaccine were lower for all current exclusive tobacco product users compared to nonusers (AORs = 0.40 to 0.70). Conclusions Continued monitoring of tobacco product use and its association with respiratory diseases such as COVID‐19 is crucial to inform public health policies and programs. In addition, efforts to promote vaccination, especially among tobacco product users, are warranted.

Smoking remains the main cause of premature death in the United States (US) and globally. 1,2Smoking and vaping are linked to lung inflammation and lowered immune response. 3,4Previous research demonstrated that smoking increases the risk and severity of multiple respiratory diseases, including chronic obstructive pulmonary disease (COPD) and lung cancer. 5Remarkably, prior studies on the impact of smoking on the clinical severity of coronavirus disease 2019 (COVID- 19) have shown conflicting results.In the early COVID-19 pandemic, some claimed protective effects of nicotine (mainly biological aspects on cell receptors) against COVID-19 infection [6][7][8] ; however, recent evidence suggests that nicotine (from any tobacco products) does not protect against COVID-19. 4,9,10The current evidence suggests that conventional cigarette smoking is associated with a greater risk of severe COVID-19 symptoms, as evidenced by the need for hospitalization. 4e adverse effects of smoking on vulnerability to respiratory infections are well-established. 11,12Nevertheless, the lack of association between current smoking and COVID-19 outcomes in some studies [13][14][15][16][17][18] may not be surprising given that the effects of testing and vaccination for COVID-19 among tobacco users have been understudied using large, nationally representative samples.In fact, current evidence on the association between smoking and COVID-19 risk is inadequate and conflicting, highlighting the need for consistent national studies with rigorous study designs. 18A cohort study 13 of vaccination against COVID indicated that vaccination was protective against death, with emphasis on current and former smokers relative to never smokers.Although evidence shows a lessened serological response to COVID-19 vaccines in smokers, 19 among vaccinated patients, current smokers had the lowest mortality rate, and former smokers and never-smokers had comparable rates. 13erefore, monitoring the frequency of receiving vaccines (though cross-sectionally) along with other characteristics of COVID-19 (e.g., symptoms) might be useful for addressing vaccine hesitancy in these groups. 20and informing tobacco users about the positive consequences of vaccines.In this study, we analyzed data from the 2021 National Health Interview Survey (NHIS) to examine the prevalence of COVID-19, testing, symptoms, and vaccine uptake among users of different tobacco products among a nationally representative sample of US adults aged ≥18 years.

| Study design and participants
NHIS is an annual, nationally representative survey of the noninstitutionalized US civilian population. 21The 2021 Sample Adult component included 29,482 adults aged ≥18 with a response rate of 50.9%. 21The Sample Adult module included specific questions about COVID-19. 21

| Covariates
Current cigarette smoking was defined as having smoked at least 100 cigarettes in one's lifetime and now smoking every day or some days.
Current use/smoking of other products (e-cigarettes (electronic nicotine delivery systems; ENDS), cigars, pipes/hookah, or smokeless tobacco) was defined as ever using the product and now smoking or using it every day or some days.Any tobacco product use was defined as ever used and now using "every day" or "some days" at least one tobacco product.Any combustible tobacco product use was defined as using on "every day" or "some days" at least one combustible tobacco product: cigarettes; cigars, cigarillos, filtered little cigars; pipes, or hookahs.Further, we defined exclusive use of each product as currently using only one product (e.g., exclusive ENDS users who did not use any other products).Response items were "no difficulty," "some difficulty," "a lot of difficulty,"

| Independent variables
or "cannot do at all." Respondents were categorized as having a disability if they reported "a lot of difficulty" or "cannot do" at all to any of the six questions mentioned earlier. 22,23These six questions are based on the short set of questions recommended by the Washington Group on Disability Statistics. 22e Kessler Psychological Distress Scale is a series of six questions that ask about feelings of sadness, nervousness, restlessness, worthlessness, and feeling like everything is an effort in the past 30 days.Participants responded on a Likert scale ranging from "None of the time" (score = 0) to "All of the time" (score = 4).Responses were summed over the six questions; individuals with a score of ≥13 were coded as having serious psychological distress, and respondents with a score of <13 were coded as not having serious psychological distress. 24ronic health condition was collected by asking, "Ever been told you had coronary heart disease, high cholesterol, angina, heart attack, stroke, cancer," or "ever had diabetes, asthma, weak/failing kidneys, weakened immune system due to prescriptions, epilepsy or having a current respiratory allergy."Those who answered "no" to all questions were considered not to have chronic health conditions.

| Data analysis
Unweighted frequencies and weighted percentages with corresponding 95% confidence intervals (CI) of measures associated with COVID-19 (e.g., ever tested) were calculated overall and by current tobacco product use and other covariates.To assess an association between each COVID-19 measure with tobacco product use, multivariable models were performed with the COVID-19 measure (i.e., being told having or tested for COVID-19, symptoms, testing, and vaccine) as the outcomes and tobacco product use as the exploratory variable controlling for all other study variables (Table 1).
Since each COVID-19-related measure was considered as an individual outcome, we included those participants who provided information for examined outcome in each regression model.Some independent variables had <1% missingness and were excluded from the analysis.All analyses were weighted using survey procedures in SAS (version 9.4; SAS Institute) to account for the complex survey design and generate nationally representative and unbiased estimates.The statistical significance level was set at α = 0.05.

| RESULTS
Among US adults in 2021, 18

| DISCUSSION
There is inconsistent evidence on whether tobacco users are at higher risk of acquiring COVID- Another interesting finding in this study was the association between hookah smoking and higher odds of getting tested for COVID-19.Unlike other tobacco products that are typically used solitarily, hookah smoking usually occurs in groups, where smokers often pass the same hose to smoke with friends. 26It is possible that because of the sharing culture of hookah smoking, smokers are more concerned regarding the risk of infection, 27 therefore, were more likely to get tested for COVID-19.Although it is hard to parse out the pipe from a hookah in NHIS (since they were asked within the same item), this finding has important public health implications while awaiting future studies to explore vaccine hesitancy and acceptance based on the specific type of tobacco product as well as the pattern of use (e.g., intensity and frequency).
Users of any tobacco product exclusive ENDS users-were more likely than nonusers to report loss of smell due to COVID-19.These results align with previous studies showing that ENDS users versus nonusers experience a higher frequency of COVID-19-related symptoms, including loss of smell. 28Knowing that a positive coronavirus infection diagnosis has been strongly correlated with changes in smell and taste, 29 our findings show that this correlation is more likely among exclusive ENDS users than non-users.However, some initial evidence suggests that constant flavoring chemical exposure, 30 particularly at high concentrations from ENDS use, may result in olfactory dysfunctions, which include a diminished sense of smell. 30,31Therefore, it is possible that COVID-19 infection could exacerbate the already diminished smell sensation among ENDS users.Nevertheless, given the study's cross-sectional design, future longitudinal studies are needed.
In general, COVID-19 vaccine hesitancy has been reported previously 20,32,33 and can stem from a combination of factors such as misinformation (or misconception), concerns about side effects and safety, distrust of the healthcare system/governments, and pre-existing beliefs about vaccines.Tobacco users, in general, hesitate to vaccinate more than nonusers. 34Although it was not the case for hookah users as alluded to above, this hesitancy could be explained by health consciousness against tobacco use. 34In other words, it is possible that adults who are more likely to seek the COVID-19 vaccine may also be more likely to refrain from tobacco use to avoid harmful consequences. 20,34Providing clear and accurate information about the vaccine through campaigns, public health messaging, and healthcare providers can aid dispel myths and provide accurate information to counteract misinformation and vaccine hesitancy, especially among tobacco users.In addition, targeted tailored health communication messaging to resonate with the values and attitudes of tobacco users, while also providing evidence-based information about the benefits of vaccination.
These study findings are subject to a few limitations.First, responses were self-reported and were not validated by biochemical testing, and recall information bias may occur.Nevertheless, selfreported smoking status correlates highly with serum cotinine levels. 35Second, because NHIS is limited to the noninstitutionalized US civilian population, the results are not generalizable to institutionalized populations such as the military.Finally, the NHIS Sample Adult response rate of 50.9% can introduce nonresponse bias.However, all analyses were weighted to avoid this limitation.