Comparison of respiratory symptoms and potentially confounding variables between welders and non-welding manual labourers who took part in the cross-sectional survey
| All N=529 | Welders n=274 | Manual labourers n=255 | p Value | |
|---|---|---|---|---|
| Age—median (IQR) | 38 (33; 45) | 38 (32; 44) | 40 (33; 46) | 0.058 |
| Nationality: n (%) | ||||
| Bangladesh | 262 (50) | 146 (53) | 116 (45) | |
| India | 182 (34) | 86 (31) | 96 (38) | |
| Philippines | 53 (10) | 30 (11) | 23 (9) | |
| Pakistan | 32 (6) | 12 (4) | 20 (8) | 0.101 |
| Smoking: n (%) | ||||
| Current | 129 (24) | 67 (24) | 62 (24) | |
| Past | 65 (12) | 34 (12) | 31 (12) | |
| Never | 334 (63) | 173 (63) | 161 (63) | 0.997 |
| Pack-years current smokers: median (IQR) | 4 (2; 8) | 5 (2; 8) | 4 (2; 7) | 0.474 |
| Tenure in years: median (IQR) | 5.9 (4.5; 8) | 5.7 (4.4; 7.1) | 6.2 (4.5; 10.5) | 0.018 |
| Past welding: n (%) | 245 (46) | 192 (70) | 53 (21) | <0.001 |
| Years of past welding: median (IQR) | 5 (6) | 5 (6) | 4 (4) | 0.121 |
| Total years of welding: median (IQR) | 9 (9) | 9 (9) | – | – |
| Daily hours* of arc welding: median (IQR) | 4 (6) | 4 (6) | – | – |
| Welding exposure: n (%) | – | – | ||
| High (>5 h) | 121 (44) | 121 (44) | – | – |
| Medium (3–5 h) | 43 (16) | 43 (16) | – | – |
| Low (<3 h) | 110 (40) | 110 (40) | – | – |
| Cutting and grinding: n (%) | 302 (57) | 230 (84) | 72 (28) | <0.001 |
| Daily hours*: median (IQR) | 3 (4) | 3 (4) | 2 (3) | 0.081 |
| Breathing mask worn while welding—n (%) | ||||
| Always | 193 (71) | 193 (71) | – | |
| Most of the time | 58 (21) | 58 (21) | – | |
| Sometimes | 19 (7) | 19 (7) | – | |
| Never | 3 (1) | 3 (1) | – | |
| Symptoms—summer: n (%) | 33 (10) | 19 (11) | 14 (9) | 0.565 |
| Symptoms—winter: n (%) | 43 (20) | 28 (26) | 15 (14) | 0.029 |
| MFF—summer: n (%) | 59 (19) | 13 (9) | 46 (28) | <0.001 |
| MFF—winter: n (%) | 31 (15) | 6 (6) | 25 (23) | <0.001 |
Bold highlights statistical significance. *Current daily hours.
MFF, metal fume fever.