Results of 1,000 Monte Carlo GAM models with imputed missing smoking information for four scenarios (in gray). Scenario a: Missing data 60% smokers. Scenario b: Missing data 15% smokers. Scenario c: Missing data positively correlated with IHD mortality (80% smokers/20% non-smokers). Scenario d: Missing data negatively correlated with IHD mortality (20% smokers/80% non-smokers). Dose-response association of main case-control model plus 95% confidence limits is shown in blue and point estimates of main case-control model additionally adjusted for original, non-imputed, smoking status are shown in red.