Assessment of smoking exposure by urine cotinine levels in severe COVID-19 patients: a case-control study
Abstract
Coronavirus Disease 2019 (COVID-19), caused by SARS-CoV-2, has posed a significant global public health challenge, with long-term sequelae such as post-COVID-19 syndrome continuing to burden health systems. Tobacco use, a major preventable cause of morbidity and mortality, impairs the immune response and exacerbates respiratory diseases, including COVID-19. Passive smoking, an important but often overlooked public health problem, exposes non-smokers to harmful health risks and may contribute to worse outcomes in respiratory disease. This study aims to investigate the relationship between smoking exposure, including passive smoking, and the severity of COVID-19 using urinary cotinine levels to provide objective insights into a critical public health issue. This prospective observational study was conducted over six months in 2021 in the ICU of a tertiary care hospital. Forty-two patients were divided into four groups based on smoking and COVID-19 status: non-smoker/non-COVID-19, smoker/non-COVID-19, non-smoker/COVID-19, and smoker/COVID-19. COVID-19 diagnosis was confirmed by RT-PCR and/or imaging. Data collected included demographic information, clinical scores [APACHE II, mSOFA, GCS], respiratory function [stPaO2/FiO2 ratio], arterial blood gas parameters and routine laboratory findings. Urinary cotinine levels were measured by ELISA and normalised to spot urine creatinine levels to ensure accuracy. Urine cotinine levels were highest in the smoker/COVID-19 group and…
How strong is the evidence?
Evidence Hub reads this as a case-control, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 19 participants or records.
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