Relation between intensity of work, work tasks and chemical exposure in 2008, and changes in FEV1 among current hairdressers between 2008 and 2013, Hebron, Palestine
| Δ FEV1 (mL/year) | ||||
|---|---|---|---|---|
| Occupational factors (n) | Mean* | Coefficient† | 95% CI | |
| Lower | Upper | |||
| Working years | ||||
| <4 (n=68) | −22 | 0 (reference) | ||
| ≥4 (n=65) | −35 | −13 | −25 | −1 |
| Working hours | ||||
| <5 (n=22) | −21 | 0 (reference) | ||
| 5–7 (n=76) | −34 | −13 | −30 | +3 |
| 8–10 (n=35) | −28 | −6 | −25 | +12 |
| Customers (per week) | ||||
| <15 (n=28) | −23 | 0 (reference) | ||
| 15–35 (n=77) | −37 | −13 | −28 | +1 |
| >35 (n=28) | −22 | +1 | −16 | +18 |
| Bleaching (per week) | ||||
| <5 (n=83) | −25 | 0 (reference) | ||
| ≥5 (n=50) | −36 | −10 | −22 | +1 |
| Dyeing (per week) | ||||
| <7 (n=64) | −32 | 0 (reference) | ||
| ≥7 (n=69) | −30 | +2 | −9 | +13 |
| Mean NH3 (ppm) | ||||
| <25 (n=24) | −35 | 0 (reference) | ||
| ≥25 (n=5) | −93 | −57 | −92 | −23 |
All occupational factors were measured in 2008 except NH3 which was measured in 2012–2013.
*Estimated annual decline of FEV1 (mL/year), adjusted for age, height and BMI.
†Difference in annual decline of FEV1 (mL/year) compared with the reference, adjusted for age, height and BMI.
BMI, body mass index; FEV1, forced expiratory volume in 1 s; ppm, part per million.