Smoking is associated with worse outcomes of COVID-19 particularly among younger adults: A systematic review and meta-analysis

Abstract

Background: Smoking impairs lung immune functions and damages upper airways, increasing risks of contracting and severity of infectious diseases. Methods: We searched PubMed and Embase for studies published from January 1-May 25, 2020. We included studies reporting smoking behavior of COVID-19 patients and progression of disease, including death. We used a random effects meta-analysis and used meta-regression and lowess regressions to examine relationships in the data. Results: We identified 47 peer-reviewed papers with a total of 31,871 COVID-19 patients, 5,759 (18.1%) experienced disease progression and 5,734 (18.0%) with a history of smoking. Among smokers, 29.2% experienced disease progression, compared with 21.1% of non-smokers. The meta-analysis confirmed an association between smoking and COVID-19 progression (OR 1.56, 95% CI 1.32-1.83, p=0.001). Smoking was associated with increased risk of death from COVID-19 (OR 1.19, 95% CI 1.05-1.34, p=0.007). We found no significant difference (p=0.432) between the effects of smoking on COVID-19 disease progression between adjusted and unadjusted analyses, suggesting that smoking is an independent risk factor for COVID-19 disease progression. We also found the risk of having COVID-19 progression among younger adults (p=0.023), with the effect most pronounced among people under about 45 years old. Conclusions: Smoking is an independent risk for having severe progression of COVID-19, including mortality. The effects seem to be higher among young people. Smoking prevention and cessation should remain a priority for the public, physicians, and public health professionals during the COVID-19 pandemic.

WITHDRAWN: Reply to "Smoker, Former Smoker and COVID-19: Nicotine Does Not Protect Against SARS-CoV-2"

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Smoking and risk of negative outcomes among COVID-19 patients: A systematic review and meta-analysis

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“…The copyright holder for this this version posted March 12, 2021. ; https://doi.org/10.1101/2021.03.11.21253207 doi: medRxiv preprint 14 is known to be associated with poorer outcomes of acute COVID-19 39 . Symptoms like fatigue or shortness of breath have initially neither been assessed by validated scoring methods nor objectivated by examinations, since at that time, the rapid acquisition of reconvalescent plasma donors was top priority.…”