Current tobacco smoking and risk of SARS-CoV-2 infection and hospitalization: Evaluating the role of socio-demographic factors and comorbidities

• Published in: Preventive medicine Vol. 172; p. 107523
• Main Authors: Young-Wolff, Kelly C., Slama, Natalie, Sakoda, Lori C., Prochaska, Judith J., Fogelberg, Renee, Alexeeff, Stacey E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2023; The Authors. Published by Elsevier Inc
• Subjects: Adult; Age; Cardiovascular Diseases; Comorbidities; Comorbidity; COVID-19; COVID-19 - epidemiology; Diabetes Mellitus - epidemiology; Ethnicity; Hospitalization; Humans; Nicotine; Race; Retrospective Studies; Risk Factors; SARS-CoV-2; Short Communication; Smoking; Tobacco; Tobacco Smoking; COVID-19; SARS-CoV-2; Tobacco; Comorbidities; Race; Hospitalization; Age; Smoking; Nicotine
• ISSN: 0091-7435; 1096-0260
• DOI: 10.1016/j.ypmed.2023.107523

Our recently published study of >2.4 million adults in Northern California indicated that current versus never-tobacco smoking was associated with lower risk of SARS-CoV-2 infection and less severe coronavirus disease 2019 (COVID-19). We extended this research by evaluating whether these associations were moderated by socio-demographic factors and medical comorbidities. This retrospective cohort study of 1,885,826 adults with current or never-smoking status in Kaiser Permanente Northern California from 3/5/2020 (baseline) to 12/31/2020 (pre-vaccine) included electronic health record-based socio-demographics (sex, age, race/ethnicity, neighborhood deprivation index (NDI)) and medical comorbidities (obesity, cardiovascular conditions, diabetes, renal disease, respiratory conditions). We estimated the adjusted risk of SARS-CoV-2 infection and hospitalization (≤30 days of infection) associated with smoking status using Cox proportional hazard regression models. We estimated associations within subgroups of socio-demographics and comorbidities, and tested for effect modification using interaction terms. During the study, 35,627 patients had SARS-CoV-2 infection. Current versus never-smoking status was associated with lower adjusted rates of SARS-CoV-2 infection (aHR ranging from 0.51 to 0.89) and hospitalization (aHR ranging from 0.32 to 0.70) within nearly every socio-demographic and comorbidity subgroup. Statistically significant interactions showed that the magnitude of protection for SARS-CoV-2 infection varied by sex, age, race/ethnicity, NDI, cardiovascular conditions and diabetes, and for SARS-CoV-2 hospitalization by age and renal disease. Taken together, results indicated that while some socio-demographics and comorbidities moderated the associations, the lower risk of SARS-CoV-2 infection and hospitalization associated with current versus never-smoking status persisted among patients regardless of socio-demographics or comorbidities.