Abstract

"Tobacco smoke is a proven risk factor for viral and bacterial respiratory infection. In adults without COPD, smoking is associated with a significant increase in the relative risk of pneumonia (OR = 2.0; 95% CI 1.24-3.24), invasive pneumococcal disease (OR = 2.6; 95% CI 1.9-3.5) and Legionella infection (OR =3.48; 95% CI 2.09-5.79). Smoking has clearly been shown to be associated with an increased risk of influenza (OR = 2.4; 95% CI 1.5-3.8), tuberculosis (OR = 2.6; 95% CI 2.2-3.1) and varicella pneumonia. In young children whose parents smoke, passive exposure to tobacco smoke is associated with an increased relative risk of seasonal infections (bronchitis, pneumonia) (OR = 1.72; CI 95% 1.55-1.91) and recurrent otitis media (OR = 1.88; 95% CI 1.02-3.49). Passive smoking also increases risk of pneumonia in adults (OR = 2.5; CI 95% 1.2-5.1). Plausible explanations of the increased risk of infection in active or passive smokers include increased bacterial adherence, decrease of lung and nasal clearance, and changes in the immune response. Conclusions: Exposure to tobacco smoke approximately doubles the risk of infection. This increased burden of infection has significant healthcare cost implications. Each infectious episode in an individual should prompt an attempt at smoking cessation"