Fig 2. Risk of contracting any infection and pneumonia, being admitted to and intensive care unit and dying by pack years and years since smoking cessation.

Hazard ratio (HR) and 95% confidence interval (CI) of contracting any infection or pneumonia; being admitted to an intensive care unit and dying for pack years (panel A) and years since smoking cessation (panel B). Adjusted for age (as time scale), sex, Charlson’s weighted comorbidity index, education, marital status, exercise, walking and alcohol consumption.