SARS-Co-V2 infection in never, former, and current tobacco/nicotine users: a cohort study of 4040 Egyptian healthcare workers

BACKGROUND: Smoking negatively impacts COVID-19 severity and adverse outcomes. Evidence on whether smoking is associated with SARS-Co-V2 infection and having a positive test is scarce, particularly from low-and middle-income countries, where most of the world’s billion smokers live. The inconsistency in relevant findings calls for study designs and analyses to account for possible confounders including background characteristics and pre-existing co-morbidities, to disentangle the specific effect of smoking. In healthcare workers (HCWs) the frequency of exposure to COVID-19 cases adds another layer of risk that was not factored in previous studies. We examined the association of HCWs’ tobacco/nicotine use (never, former, and current use) with having a positive SARS-Co-V2 test result and symptoms suggestive of infection, accounting for demographics, exposures, and co-morbidities. METHODS: A prospective cohort study of 4040 healthcare workers with baseline and follow-up screening took place during April–June 2020 in 12 healthcare facilities in Cairo, Egypt. Data on demographics, tobacco/nicotine use (manufactured or roll-your-own cigarettes, waterpipe tobacco, and electronic devices), co-morbidities, symptoms, exposures, and SARS-Co-V2 investigations were analyzed. Multinomial and multivariable logistic regression analyses were performed. RESULTS: Overall, 270/4040 (6.7, 95%CI: 5.9–7.5) had positive SARS-CoV-2 tests, 479 (11.9%) were current and 79 (2.0%) were former tobacco/nicotine users. The proportion of positive tests was 7.0% (243/3482, 95%CI: 6.1–7.8) among never, 5.1% (4/79, 95%CI: 0.1–10.0) among former, and 4.8% (23/479, 95%CI: 2.9–6.7) among current users. HCWs’ SARS-CoV-2 test results did not vary significantly by single/multiple or daily/non-daily tobacco/nicotine use. Compared to never users, former users were more likely to self-report a pre-existing medical condition (OR(adjusted)1.87, 95%CI: 1.05–3.33, p = 0.033), and to experience symptoms suggestive of COVID-19 (OR(adjusted)1.76, 95%CI: 1.07–2.90, p = 0.027). After adjustment, former (OR(adjusted)0.45, 95%CI: 0.11–1.89, p = 0.273) and current (OR(adjusted)0.65, 95%CI: 0.38–1.09, p = 0.101) tobacco/nicotine use was not associated with HCWs’ SARS-CoV-2 positive test results. CONCLUSIONS: This is the first report on this association from low- and middle-income countries with high tobacco/nicotine use prevalence. In this HCW cohort, having a positive SARS-CoV-2 test was not associated with tobacco/nicotine use after accounting for demographics, exposures, and co-morbidities. Additional population-based studies could use such preliminary evidence to investigate this controversial association. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-021-11290-x.