1. Supplementary Table 1. Impact of pretransplant factors on the incidence of pulmonary complications FactorUnivariate RR (95% CI)P-valueMultivariate RR *1 (95% CI)P-valueMultivariate RR *1*2 (95% CI)P-value Age < 42 years1.00 ≥ 42 years1.31 (0.86-1.99)0.21 Sex Male1.00 Female0.65 (0.41-1.01)0.06 Disease risk *3 Low1.00 High1.57 (1.03-2.38)0.041.61 (1.04-2.48)0.031.60 (1.04-2.46)0.03 Stem cell source Bone marrow1.00 Peripheral blood0.48 (0.22-1.06)0.07 Cord blood1.52 (0.87-2.66)0.14 Donor type Related1.00 Unrelated2.10 (1.22-3.62)< 0.012.09 (1.20-3.67)0.011.93 (1.09-3.41)0.02 Conditioning regimen Myeloablative1.00 Reduced intensity1.53 (0.98-2.38)0.06 GVHD prophylaxis Cyclosporine-based1.00 Tacrolimus-based1.18 (0.79-1.76)0.44 Smoking dose (BI) 01.00 1-3991.51 (0.92-2.47)0.111.43 (0.87-2.36)0.16 ≥ 4002.02 (1.21-3.35)< 0.011.78 (1.06-3.00)0.03 Smoking dose (BI *2 per 10)1.01 (1.00-1.01)< 0.011.01 (1.00-1.01)0.02 Abbreviations: RR, relative risk; CI, confidence interval; BI, Brinkman index *1: The variables with P < 0.05 on univariate analysis were subjected to multivariate analysis. *2: BI was treated as a continuous variable *3: Low-disease risk included acute leukemia in first complete resmission (CR), chronic myelogenous leukemia in first chronic phase, myelodysplasia refractory anemia, malignant lymphoma in CR and non-malignant hematologic diseases; while high-disease risk included all other diagnoses.

2. Supplementary Table 2. Causes of pulmonary complications Never smokers (N=31) Smokers Low-dose (BI, 1-399) (N=31) High-dose (BI ≥400) (N=28) Infection Pneumonia21 (17%)23 (25%)22 (33%) Tuberculosis1 (1%)01 (2%) Non-infection Organizing pneumonia4 (3%)3 (3%)2 (3%) Interstitial pneumonia4 (3%)1 (1%)1 (2%) Bronchiolitis obliterans1 (1%)3 (3%)1 (2%) Pulmonary veno-occlusive disease01 (1%)0 Lung cancer001 (2%) Abbreviation: BI, Brinkman index

3. Supplementary Table 3. Causes of death (N = 122) Never smokers (N=58) Smokers Low-dose (BI, 1-399) (N=37) High-dose (BI ≥400) (N=37) Disease progression19 (33%)11 (30%)13 (35%) Non-relapse mortality Pulmonary Pneumonia 14 (24%)5 (14%)10 (27%) Bronchiolitis obliterans01 (3%)0 Alveolar hemorrhage01 (3%) Interstitial pneumonia1 (2%)1 (3%)0 Infections other than pneumonia10 (17%)7 (18%)3 (7%) GVHD3 (5%)3 (8%)4 (11%) VOD/TMA3 (5%)2 (5%)0 Organ failure3 (5%)3 (8%)3 (7%) Others5 (9%)3 (8%)3 (7%) Abbreviations: BI, Brinkman index; GVHD, graft-versus-host disease; VOD, veno-occlusive disease; TMA, thrombotic microangiopathy