Potential confounders of the association between physical exposure at work and neck pain
| Potential confounders in the analyses |
| Physical factors at work: |
| Number of times lifting 25 kg or more per 8 hour working day (no lifts, 0–25 times, >25 times) |
| Percentage of the working time with a minimum of 60° upper arm elevation (<5%, 5–25%, >25%)2-150 |
| Percentage of the working time carrying out repeated movements more than 4 times/minute (0%, 0–50%, >50%) |
| Video display terminal work (seldom or never, sometimes, quite often, very often) |
| Working with the hands above shoulder level (seldom or never, sometimes, quite often, very often) |
| Working with vibrating tools (seldom or never, sometimes, quite often, very often)2-150 |
| Driving a vehicle (seldom or never, sometimes, quite often, very often)2-150 |
| Frequent flexion or rotation of the upper part of the body (seldom or never, sometimes, quite often, very often)2-150 |
| Physical factors outside work: |
| Prolonged sitting (seldom or never, sometimes, quite often or very often) |
| Video display terminal work (seldom or never, sometimes, quite often or very often)2-150 |
| Activities with the hands above shoulder level (seldom or never, sometimes, quite often or very often)2-150 |
| Force exertion with hand or arms (seldom or never, sometimes, quite often or very often)2-150 |
| Activities in the same posture for a long time (seldom or never, sometimes, quite often or very often)2-150 |
| Working with vibrating tools (seldom or never, sometimes, quite often or very often) |
| Frequent flexion or rotation of the upper part of the body (seldom or never, sometimes, quite often or very often) |
| Repeated movements with hands or arm many times per minute (seldom or never, sometimes, quite or very often) |
| Driving a vehicle (seldom or never, sometimes, quite often or very often)2-150 |
| Frequency of sports or heavy physical activities which cause sweating during the past 4 months (>3 times/week, 1–2 times/week, 1–3 times/month,<1 time/month) |
| Psychosocial factors at work: |
| Quantitative job demands (low, medium, high)2-150 |
| Decision latitude (high, low)2-150 |
| Supervisor support (high, medium, low) |
| Coworker support (high, medium, low)2-150 |
| Job security (agree, disagree) |
| Individual characteristics: |
| Sex (male, female)2-150 |
| Age (continuous variable) |
| Body mass index (<25, 25–30, >30) |
↵2-150 p<0.25, Univariate association with neck pain.