| Occupational Group | N | Mean Age (Years) | SD | P value |
| Welding and metal | 42 | 31.59 | 9.32 |
|
| Paint and pigment | 38 | 35.13 | 10.65 |
|
| Radiator and auto mechanic | 37 | 34.91 | 8.65 | 0.172 |
| Battery worker | 37 | 36.97 | 10.06 |
|
| Petrol worker | 36 | 35.75 | 11.10 |
|