Smoking is Associated with Infection Risk in Healthy Blood Donors

Objectives: There is a gap in knowledge about the effects of smoking on overall infection risk in other-wise healthy populations, possibly leading to underestimation of the dangers of smoking. The present study aimed to examine the association of smoking with the risk of infections in a large cohort of healthy blood donors.Methods: This cohort study used questionnaire and health register data from 127 831 Danish blood donors. Multivariable Cox proportional hazards analysis was applied to estimate the association of current smoking with the risk of all-cause infection defined as hospital-based treatment for infection or filled prescriptions of antimicrobials stratified for age and adjusted for relevant confounders.Results: Among 18 272 current smokers, 12 272 filled an antimicrobial prescription and 2035 received hospital-based treatment for infections. Among 101 974 non-smokers, 65 117 filled a prescription and 8501 received hospital-based treatment for infections. Smokers had a higher risk of all-cause infection than non-smokers (hazard ratio estimates were 1.27 in males and 1.33 in females for hospital-based treatment and 1.11 in males and up to 1.20 in females for filled prescriptions). Smoking was most strongly associated with an increased incidence of respiratory tract infection, abscesses, skin infection, and prescriptions for these ailments (hazard ratio up to 2.29). Furthermore, smokers' risk of filled pre-scriptions of broad-spectrum penicillin was increased (hazard ratio up to 1.96).Conclusions: Current smoking was strongly associated with the risk of hospital-based treatment of infection and filled prescriptions of antimicrobials in a large cohort of healthy individuals. These findings warrant an increased focus on infectious disease risk among smokers. Bertram Kjerulff, Clin Microbiol Infect 2023;29:506 (c) 2022 The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/).