Demographic characteristics of participants (N=6960) and non-participants (n=15 324)
| Participants | % | Non-participants | % | |
| Sex | ||||
| Women | 150 | 2.2 | 192 | 1.2 |
| Men | 6810 | 97.8 | 15 132 | 98.8 |
| Age | ||||
| <30 years | 1690 | 24.3 | 4744 | 31.0 |
| ≥30 years | 5270 | 75.7 | 10 580 | 69.0 |
| Education | ||||
| Apprentice | 1209 | 17.4 | ||
| Trained electrician | 5100 | 73.3 | ||
| Higher education | 391 | 5.6 | ||
| Other education | 203 | 2.9 | ||
| Missing | 57 | 0.8 | ||
| Seniority | ||||
| Mean number of years working with electricity (SD) | 19 | (13.9) | ||
| Marital status | ||||
| Married or cohabiting | 5059 | 72.7 | ||
| Single (bachelor) | 1189 | 17.1 | ||
| Single (divorced or widowed) | 585 | 8.4 | ||
| Missing | 127 | 1.8 | ||
| Current work situation | ||||
| Working with electricity | 5952 | 85.5 | ||
| Working with something other than electricity | 659 | 9.5 | ||
| Not working (on leave, unemployed, sick leave, other) | 245 | 3.5 | ||
| Missing | 104 | 1.5 | ||
| Self-reported health (general health item from SF-36) | ||||
| Excellent, very good, good | 6363 | 91.5 | ||
| Fair, poor | 525 | 7.5 | ||
| Missing | 72 | 1.0 | ||
| Smoking | ||||
| Yes, currently a smoker | 1222 | 17.5 | ||
| No, but previously smoked | 1856 | 26.7 | ||
| No, never smoked | 3806 | 54.7 | ||
| Missing | 76 | 1.1 | ||
| Alcohol use | ||||
| 0 units/week | 1935 | 27.8 | ||
| 1–14 units/week | 4636 | 66.6 | ||
| 15 or more units/week | 318 | 4.6 | ||
| Missing | 71 | 1.0 | ||
| Body mass index | ||||
| <18.5 underweight | 51 | 0.7 | ||
| 18.5–<25 normal weight | 2322 | 33.4 | ||
| 25–<30 overweight | 2895 | 41.6 | ||
| 30+ obese | 1527 | 21.9 | ||
| Missing | 165 | 2.4 |