The study presents an analysis of the current smoking prevalence among hospitalized patients with COVID-19 in China, compared to the population smoking prevalence in China (52.1% in males and 2.7% in females). Through a systematic research of the literature (PubMed) we identified 7 studies examining the clinical characteristics of a total of 2352 hospitalized COVID-19 patients that presented data on the smoking status.
The expected number of smokers was calculated using the formula Expected smokers = (males x 0.521) + (females x 0.027). An unusually low prevalence of current smoking was observed among hospitalized COVID-19 patients (8.7%, 95%CI: 7.6-9.9%) compared to the expected prevalence based on smoking prevalence in China (30.3%, 95%CI: 28.4-32.1%; z-statistic: 22.80, P < 0.0001). This preliminary analysis does not support the argument that current smoking is a risk factor for hospitalization for COVID-19, and might even suggest a protective role.
The latter could be linked to the down-regulation of ACE2 expression that has been previously known to be induced by smoking. However, other confounding factors need to be considered and the accuracy of the recorded smoking status needs to be determined before making any firm conclusions. As a result, the generalized advice on quitting smoking as a measure to improve health risk remains valid, but no recommendation can currently be made concerning the effects of smoking on the risk of hospitalization for COVID-19.
No studies recording e-cigarette use status among hospitalized COVID-19 patients were identified. Thus, no recommendation can be made for e-cigarette users. – READ MORE
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