Incidence and Case-Fatality Ratio of COVID-19 infection in relation to Tobacco Smoking, Population Density and Age Demographics in the USA: could Particulate Matter derived from Tobacco Smoking act as a Vector for COVID-19 transmission?

  1. Yves Muscat Baron

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

BACKGROUND

Tobacco smoking is known to increase the risk for bacterial and viral respiratory infections and this also applies to second-hand smoking. Smoking has been shown to increase the severity of COVID-19 infection and the consequent risk for intra-tracheal ventilation in smokers. Tobacco smoking exposes the user and nearby individuals to very high concentrations of particulate matter in a short period of time. Genes appertaining to COVID-19 have been found adherent to particulate matter. Particulate matter has been shown to travel beyond the social distance of 2 metres up to 10 metres. COVID-19 related mortality has been linked to elevated atmospheric levels of the particulate matter, PM2.5. The aim of the study was to observe the incidence of infection rate and case fatality ratios in the USA, comparing States with partial bans on tobacco smoking, to States with more restrictive smoking regulation, exploring a possible link between smoke-related particulate matter and COVID-19 transmission.

METHODOLOGY

Two groups of USA States, differentiated by the degree of smoking legislative restrictions, had a number of variables compared. The incidence of COVID-19 infection, case-fatality ratio and testing frequency were obtained from the John Hopkins Coronavirus Resource Centre. The degree of smoking bans in the USA States was obtained from the websites of the Nonsmokers Rights Foundation. The percentage of the State population which smokes was collected from the Centres of Disease Control database. Population density, Body Mass Index and population percentages of individuals 65+/75+years were obtained from databases concerning USA demographics.

RESULTS

With the available data there was no significant difference in COVID-19 testing prevalence between the partial smoking ban group and the more restrictive regulated group. The incidence of COVID-19 infection in the States with limited bans on tobacco smoking was 2046/100,000 (sd+/-827) while the infection incidence in States with more restrictive rulings on tobacco smoking was 1660/100,000 (sd+/-686) (p<0.038). The population percentage of smokers in States with minor limitations to smoking was 18.3% (sd+/-3.28), while States with greater smoking restrictions had a smoking population percentage of 15.2% (sd+/-2.68) (p<0.0006).

The two populations of both groups did not differ numerically (p<0.24) and numbered 157,820,000 in the partial smoking ban group and 161,439,356 in the more restrictive group. Population density correlated significantly with the case-fatality ratio (R=0.66 p<0.0001), as did the 75+year age group (R=0.29 p<0.04). Reflecting the possibility of trans-border transmission, the smoking status of adjacent partial smoking ban States may influence the COVID-19 incidence of bordering States (e.g. Utah) even if the smoking regulations of the latter were stricter than the former.

Other factors that could impact the COVID-19 pandemic in the USA such as the State case-fatality ratio, population density, population percentage with elevated body mass index and the percentage of the state population aged 65years or above did not show any significant difference between both groups of States.

CONCLUSION

States in the USA with high levels of tobacco smoking and limited regulation had significantly higher rates of COVID-19 infection incidences than States with greater smoking restrictions. Population density and the age group of 75+years, showed a positive significant correlation with the case-fatality ratio. Besides the adverse effects of tobacco smoking on pulmonary defences, it would be interesting to explore the possibility of infection transmission via coronavirus-laden particulate matter from exhaled fumes derived from tobacco smoking.

Article activity feed

  1. ScreenIT

    SciScore for 10.1101/2020.10.04.20206383: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    There a number of limitations to the observations noted in this paper. There is some asynchrony in a number variables assessed. The population percentage of smokers was derived from 2018 data from the Centre of Disease Centre and Prevention. This also applies to the States’ population, population density and percentage of individuals deemed overweight or obese. The data regarding incidence of COVID-19 infection, case-fatality ratio and testing frequency were collected over the period between the 18th and 25th September so as to reduce the bias for the constantly evolving fluctuations. Testing frequency was not available for all States, however there did not appear a significant difference of the testing frequency between both groups of states in the data available. Not all the required data from the District of Columbia, Puerto Rico, American Samoa and North Mariana Islands was available for assessment, so these territories were excluded from this study. These four regions constitute 1.37% of the whole USA population. The paper did not review the inter-State differences in infrastructure, healthcare provision, lifestyle differences and the poverty index, all of which may directly or indirectly impact on infection transmission and case-fatality ratios. Moreover the State bans considered were those imposed in 2018 and since then smoking regulations may have been altered. This study presupposes the unlikely assumption that adherence to smoking bans is enacted across the USA unif...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2020.10.04.20206383v1 on medRxiv