Table 1 Sample description
Variable | No COPD n = 279 | COPD n = 21 | Total n = 300 | p-value |
|---|---|---|---|---|
Gender, women, n (%) | 141 (50.5) | 10 (47.6) | 151 (50.3) | 0.07 |
Mean age, years, m (SD) | 52.2 (5.3) | 53.5 (5.4) | 52.3 (5.3) | 0.22 |
Age category, n (%) | ||||
40–45 | 38 (13.6) | 2 (9.5) | 40 (13.3) | |
45–50 | 43 (15.4) | 2 (9.5) | 45 (15.0) | |
50–55 | 91 (32.6) | 7 (33.3) | 98 (32.7) | |
55–60 | 98 (35.1) | 8 (38.1) | 106 (35.3) | |
60 + | 9 (3.2) | 2 (9.5) | 11 (3.7) | 0.55 |
BMI (kg/m2), m (SD) | 26.0 (4.3) | 25.3 (4.4) | 25.9 (4.3) | 0.67 |
Ethnicity, n (%) | ||||
Caucasian | 225 (80.6) | 17 (81.0) | 242 (80.7) | |
African | 44 (15.8) | 4 (19.0) | 48 (16.0) | |
Other | 4 (1.4) | 0 (0.0) | 4 (1.3) | 0.84 |
Smoking category, n (%) | ||||
Non smoker | 147 (52.7) | 7 (33.3) | 154 (51.3) | |
Current smoker | 95 (34.1) | 13 (61.9) | 108 (36.0) | |
Ex-smoker | 37 (13.3) | 1 (4.8) | 38 (12.7) | 0.04 |
Tobacco exposure, pack-years, m (SD) | 14.8 (14.6) | 21.5 (17.2) | 15.4 (14.9) | 0.11 |
Occupation, n (%) | 0.91 | |||
Station agent | 123 (44.1) | 9 (42.9) | 132 (44.0) | |
Locomotive operator | 113 (40.5) | 8 (38.1) | 121 (40.3) | |
Security guard | 43 (15.4) | 4 (19.0) | 47 (15.7) | |
Employement duration, years, m (SD) | 24.0 (6.1) | 24.9 (7.5) | 24.1 (6.2) | 0.54 |
Spirometry, m (SD) | ||||
FEV1% predicted (GLI) | 99.3 (13.1) | 83.6 (17.0) | 98.2 (14.0) | < 0.001 |
FVC % predicted (GLI) | 101.1 (12.9) | 103.6 (17.8) | 101.2 (13.2) | 0.26 |
FEV1/FVC % predicted (GLI) | 98.0 (5.4) | 80.0 (6.8) | 96.7 (7.2) | < 0.001 |
FEF 25–75% predicted (GLI) | 97.7 (28.2) | 48.1 (18.7) | 94.2 (30.4) | < 0.001 |
COPD Stage, n (%) | ||||
PRISm | 18 (6.5) | - | - | |
Pre-COPD: At-risk | 63 (22.6) | - | - | |
GOLD 1: Mild | - | 12 (57.1) | - | |
GOLD 2: Moderate | - | 8 (38.1) | - | |
GOLD 3: Severe | - | 1 (4.8) | - | |
GOLD 4: Very severe | - | 0 (0.0) | - | |
Self declared symptoms, n (%) | ||||
Cough | 44 (15.8) | 11 (52.4) | 55 (18.3) | < 0.001 |
Phlegm | 41 (14.7) | 6 (28.6) | 47 (15.7) | 0.11 |
Shortness of breath (Dyspnea) | 40 (14.3) | 4 (19.0) | 44 (14.7) | 0.53 |
Wheezing | 22 (7.9) | 5 (23.8) | 27 (9.0) | < 0.01 |
At least one above symptom | 90 (32.2) | 12 (57.1) | 102 (34.0) | 0.01 |
Mean number symptoms above, m (SD) | 0.5 (0.9) | 1.2 (1.4) | 0.6 (1.0) | 0.03 |
At least one COPD symptom exacerbation | - | 7 (33.3) | - | |
Medical history, n (%) | ||||
Asthma | 27 (9.7) | 3 (14.3) | 30 (10.0) | 0.42 |
Bronchitis | 7 (2.5) | 1 (4.8) | 8 (2.7) | 0.45 |
COPD | 0 (0.0) | 2 (9.5) | 2 (0.7) | 0.44 |
Emphyzema | 3 (1.1) | 2 (9.5) | 5 (1.7) | < 0.01 |
Eczema | 56 (20.1) | 3 (14.3) | 59 (19.7) | 0.04 |
Pollen Allergies | 60 (21.5) | 6 (28.6) | 66 (22.0) | 0.78 |