Relation of smoking behaviour with severity of COVID-19 infections in a sample of Iraqi patients

This cross-sectional study done in 658 adult Iraqi patients (aged 20 to 39) did not find an association between smoking habit, its types and frequencies with the severity of COVID-19 symptoms.

The World Health Organization (WHO) reported that smokers have a higher risk of developing severe disease with COVID-19 compared to non-smokers[1]. However, a few reports refuted this relationship [2] despite established knowledge that smoking raises the risk of bacterial and viral illness infections, especially respiratory infections [3]. We have examined the differences in COVID-19 symptom severity between smokers and non-smokers, its frequency and type with COVID-19 symptom severity in a sample of Iraqi COVID-19 recovered individuals.

We have recruited 658 (411 women and 247 men) COVID-19 Iraqi patients (aged 20-39) who recovered from a recent attack (before two weeks) of COVID-19 at Al-Yarmok Teaching Hospital and Al-Shifa Medical Centre between January and August 2021. Their participation was voluntary, and informed consent was obtained. The data collection questionnaire included age, sex, severity of symptoms (severe: symptoms that required hospitalisation and oxygenation therapy; moderate: those bedridden; and mild: flue-like symptoms), and smoking, its frequency (daily, non-daily) and types (cigarette, hookah, both). We excluded those with asthma, chronic respiratory, and other chronic systemic diseases.

The key results of the chi-square analysis are presented in Table 1. The smoking proportions, frequencies, and types are similar across the COVID-19 severity categories (P>0.1 for all). Nicotine has been demonstrated to impede the growth of SARS-CoV-2, possibly by reducing the lungs' cytokine storm and lessening the severity of COVID-19 infection [4]. However, smoking is arguably the biggest risk factor that can be avoided [5]. Giving up smoking can reduce SARS-CoV-2 infection risk in addition to illnesses associated with tobacco use [6]. Nicotine increases the amount of viral entry, and SARS infection downregulates the expression of angiotensin-converting enzyme-2 as a regulatory mechanism after infection [7]. Well-designed clinical trials are necessary to examine the effect of nicotine on this.

According to the German news website N-TV, a medical team at Pitié Salpêtrière Hospital in the French capital, Paris, conducted a study that suggested nicotine may have protective properties against the COVID-19 virus, meaning that smokers may be less likely to get the virus than non-smokers [2].  This finding has surprised the scientific community because the harms of smoking are beyond debate nowadays [8]. There are reports of higher mortality among smokers compared to non-smokers. Well-designed studies do not refute the smoking habits' putative effect on COVID-19.1 Our results agree with a few previous studies that smoking’s association with COVID-19 severity is not cognisable. While tobacco smoking may provide some protection against respiratory infections, it is a potentially dangerous chemical that may negatively affect the respiratory epithelium and health in general. In conclusion, we did not find any protective or putative relationship between smoking and COVID-19 severity in this Iraqi sample of post-COVID-19 patients.

Table 1 Smoking behaviour of patients with severity of COVID 19 patients, results are number (percent)a

We acknowledge the COVID-19 Centers in Al-Karkh and Al-Rusafa for their assistance in this work.

Conception or design of the work; or the acquisition, analysis, or interpretation of data for the work: KIN, NHK, MES, RHG. Drafting the work or reviewing it critically for important intellectual content: KIN, NHK, MES, RHG. Final approval of the version to be published: KIN, NHK, MES, RHG. Accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: KIN.

We do not have any conflict of interest.

We confirm that the data supporting the findings of the study will be shared upon reasonable request. 

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