COVID-19, smoking and inequalities: a study of 53 002 adults in the UK

  1. Sarah E Jackson
  2. Jamie Brown
  3. Lion Shahab
  4. Andrew Steptoe
  5. Daisy Fancourt

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

This study aimed to examine associations between smoking and COVID-19 relevant outcomes, taking into account the influence of inequalities and adjusting for potential confounding variables.

Methods

Cross-sectional data were used from an online study of adults in the UK (n=53 002). Main outcome measures were confirmed and suspected COVID-19, worry about catching or becoming seriously ill from COVID-19 and adherence to protective behaviours. Covariates included age, sex, ethnicity, education (post-16 qualifications: yes/no), key worker status and comorbid health conditions.

Results

Compared with never smokers (0.26% (95% CI 0.21% to 0.33%)), prevalence of confirmed COVID-19 was higher among current (0.56% (0.41% to 0.75%)) but not ex-smokers (0.19% (0.13% to 0.28%)). Associations were similar before (current: OR=2.14 (1.49–3.08); ex-smokers: OR=0.73 (0.47–1.14)) and after (current: OR=1.79 (1.22–2.62); ex-smokers: OR=0.85 (0.54–1.33)) adjustment. For current smokers, this was moderated by socio-economic position, with higher rates only seen in those without post-16 qualifications (OR=3.53 (2.04–6.10)). After including suspected cases, prevalence was higher among current smokers (11.2% (10.6% to 11.9%), OR=1.11 (1.03–1.20)) and ex-smokers (10.9% (10.4% to 11.5%), OR=1.07 (1.01–1.15)) than never smokers (10.2% (9.9% to 10.6%)), but remained higher only among ex-smokers after adjustment (OR=1.21 (1.13–1.29)). Current and ex-smokers had higher odds than never smokers of reporting significant stress about becoming seriously ill from COVID-19 (current: OR=1.34 (1.27–1.43); ex-smokers: OR=1.22 (1.16–1.28)). Adherence to recommendations to prevent spread of COVID-19 was high (96.3% (96.1% to 96.4%)), but lower among current than never smokers (OR=0.70 (0.62–0.78)).

Conclusions

In a population sample, current smoking was independently associated with self-reported confirmed COVID-19 infection. There were socio-economic disparities, with the association only apparent among those without post-16 qualifications. Smokers reported lower adherence to guidelines despite being more worried than non-smokers about catching or becoming seriously ill from COVID-19.

Article activity feed

  1. Version published to 10.1136/tobaccocontrol-2020-055933
  2. ScreenIT

    SciScore for 10.1101/2020.04.30.20086074: (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

    Software and Algorithms
    SentencesResources
    Analyses were conducted on complete cases using SPSS v.24.
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    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 were also several limitations. First, rates of COVID-19 testing are lower in the UK than many other countries, suppressing numbers of confirmed COVID-19 cases; but this would only affect our results if testing rates differed by smoking status. Secondly, recency of cessation among former smokers was not assessed, so this group ranges from those who stopped smoking many years or decades previously to those who quit in the days or weeks prior to the survey. Future studies should ask former smokers about time since quitting in order to better evaluate whether abrupt quitting following the onset of COVID-19 symptoms may contribute to the lower rates of smoking recorded among hospitalised patients (4,16,17). Thirdly, the measure of smoking less underestimates those making reductions in their smoking because those who quit altogether in the last week are not included. Fourthly, the measure of changes in smoking was not anchored to the pandemic (i.e. did not ask about changes since COVID-19 started to affect the respondent’s life), so may not be sensitive to detect early changes in smoking in response to the pandemic. We observed associations between the date participants completed the survey and the odds of smoking less (which decreased over time) and smoking more (increased over time), which suggests changes in smoking behaviour in reaction to the pandemic may be changing as time passes, possibly in response to conflicting messages on smoking increasing or decreasing COVID-19...

    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.

  3. Version published to 10.1101/2020.04.30.20086074v1 on medRxiv