Some demographic and exposure characteristics of the study group
| Characteristic |
Company A n (%) |
Company B n (%) |
Total n (%) |
| Sex: | |||
| Men | 77 (87) | 37 (90) | 114 (88) |
| Women | 12 (13) | 4 (10) | 16 (12) |
| Age (y): | |||
| 20–29 | 14 (16) | 7 (17) | 21 (16) |
| 30–39 | 27 (30) | 8 (20) | 35 (27) |
| 40–49 | 21 (24) | 13 (32) | 34 (26) |
| 50–59 | 24 (27) | 11 (27) | 35 (27) |
| ⩾60 | 3 (3) | 2 (5) | 5 (4) |
| Body mass index:3-150 | |||
| 18.5–24.9 (normal weight) | 29 (33) | 12 (29) | 41 (31) |
| 25.0–29.9 (grade 1 overweight) | 45 (51) | 17 (41) | 62 (48) |
| 30.0–34.9 (grade 2 overweight) | 11 (12) | 8 (20) | 19 (15) |
| 35.0–39.9 (grade 2 overweight) | 4 (4) | 4 (10) | 8 (6) |
| Smoking habits: | |||
| Non-smokers | 40 (45) | 19 (46) | 59 (45) |
| Ex-smokers | 27 (30) | 13 (32) | 40 (31) |
| Smokers | 22 (25) | 9 (22) | 31 (24) |
| Duration of employment (y): | |||
| –5 | 10 (11) | 6 (15) | 16 (12) |
| 5–9 | 29 (33) | 12 (29) | 41 (32) |
| 10–14 | 20 (22) | 6 (15) | 26 (20) |
| 15–19 | 8 (9) | 5 (12) | 13 (10) |
| 20–29 | 17 (19) | 9 (22) | 26 (20) |
| ⩾30 | 5 (6) | 3 (7) | 8 (6) |
| Total | 89 | 41 | 130 |
↵3-150 Classification according to the World Health Organisation.18