| Ever-smokers | DLCO >60% pred | DLCO ≤60% pred | p-value | Never-smokers | DLCO >60% pred | DLCO ≤60% pred | p-value | |
| Subjects n | 125 | 78 | 47 | 33 | 25 | 8 | ||
| Age | 46.1±9.2 | 45.4±10.0 | 47.3±7.6 | 0.25 | 48.8±10.7 | 48.4±11.6 | 50.0±8.2 | 0.71 |
| Female | 38 (30.4) | 25 (32.1) | 13 (26.7) | 0.61 | 7 (21.2) | 4 (16.0) | 3 (37.5) | 0.32 |
| African American | 70 (56.0) | 43 (55.1) | 27 (57.5) | 0.37 | 10 (30.3) | 7 (28.0) | 3 (37.5) | 0.61 |
| HIV risk factor | 0.26 | 0.28 | ||||||
| MSM | 60 (48.4) | 39 (50.0) | 21 (44.7) | 18 (54.6) | 15 (60.0) | 3 (37.5) | ||
| Heterosexual contact | 41 (30.1) | 28 (35.9) | 13 (27.7) | 10 (30.3) | 7 (28.0) | 3 (37.5) | ||
| Intravenous drug use | 15 (12.1) | 6 (7.7) | 9 (19.1) | 0 (0) | ||||
| Blood transfusion/unknown/refused | 9 (7.2) | 5(6.4) | 3 (6.4) | 5 (15.2) | 3 (12.0) | 2 (20.0) | ||
| Body mass index | 26.7±5.7 | 27.5±5.7 | 25.4±5.5 | 0.02 | 27.3±5.2 | 26.6±4.9 | 29.3±6.1 | 0.21 |
| Smoking status | 0.14 | NA | ||||||
| Never | 33 (100) | 25 (100) | 8 (100) | |||||
| Former | 39 (31.2) | 28 (35.9) | 11 (23.4) | |||||
| Current | 86 (68.8) | 50 (64.1) | 36 (76.6) | |||||
| Pack-years smoked | 14.2 (0–75) | 10 (0–75) | 17.4 (0–70) | 0.03 | 0 (0–0) | 0 (0–0) | 0 (0–0) | NA |
| Secondhand smoke exposure# | ||||||||
| Childhood home | 77 (78.6) | 40 (69.0) | 37 (92.5) | 0.01 | 19 (70.4) | 14 (70.0) | 5 (71.4) | 0.94 |
| Adult home | 83 (84.7) | 48 (82.8) | 35 (87.5) | 0.52 | 20 (74.1) | 14 (70.0) | 6 (85.7) | 0.63 |
| Adult outside of home | 85 (86.7) | 50 (86.2) | 35 (87.5) | 0.85 | 18 (66.7) | 13 (65) | 5 (71.4) | 0.76 |
| Marijuana use ever | 80 (64.0) | 51 (65.4) | 29 (61.7) | 0.68 | 8 (24.2) | 5 (20.0) | 3 (37.5) | 0.37 |
| Cocaine use ever | 34 (27.2) | 16 (20.5) | 18 (38.3) | 0.03 | 3 (9.1) | 2 (8.0) | 1 (12.5) | 1.0 |
| Hepatitis C | 19 (15.2) | 11 (14.1) | 8 (17.2) | 0.68 | 5 (15.2) | 4 (16.0) | 1 (12.5) | 1.0 |
| Occupational exposure | 30 (24.0) | 18 (23.1) | 12 (25.5) | 0.76 | 6 (18.2) | 5 (20.0) | 1 (12.5) | 0.63 |
| Using pneumonia prophylaxis | 38 (30.4) | 23 (29.5) | 15 (31.9) | 0.85 | 7 (21.2) | 6 (24.0) | 1 (12.5) | 0.65 |
| Prior pneumonia | 32 (25.6) | 21 (20.6) | 17 (31.5) | 0.13 | 6 (18.2) | 4 (16.0) | 2 (25.0) | 0.62 |
| Prior Pneumocystis pneumonia | 3 (2.4) | 2 (2.6) | 1 (2.1) | 0.81 | 0 | NA | ||
| Antiretroviral use | 110 (88.0) | 67 (85.9) | 43 (91.5) | 0.35 | 27 (81.8) | 20 (80.0) | 7 (87.5) | 1.0 |
| CD4+ T-lymphocytes per μL | 561.5 (24–2094) | 571 (33–2094) | 528.5 (24–1798) | 0.59 | 533 (179–1327) | 513 (179–1140) | 685.5 (265–1327) | 0.48 |
| Plasma HIV RNA ln copies·mL−1 | UD (UD–13.2) | UD (UD–13.2) | UD (UD–12.1) | 0.88 | UD (UD–13.7) | UD (UD–13.7) | UD (UD–8.9) | 0.65 |
| DLCO % pred | 64.1 (15.0) | 73.0 (9.5) | 49.4 (10.0) | NA | 72.7 (13.4) | 78.1 (10.5) | 55.8 (3.5) | NA |
Data are presented as mean±sd, n (%) or median (range), unless otherwise stated. DLCO: diffusing capacity of the lung for carbon monoxide; % pred: % predicted; MSM: males who have sex with males; NA: not available; UD: undetectable. #: data on secondhand smoke exposure was collected for 125 participants, 98 smokers and 27 never-smokers. p-values represent comparisons between the participants with DLCO >60% pred and those with a DLCO ≤60% pred.