Table 3.
Univariate and multivariate effects of working conditions on PTB and its subtypes: ABCD study, Amsterdam, the Netherlands, 2003–2004 (N=7561)
| Total PTB | Spontaneous PTB | Iatrogenic PTB | ||||
| Crude | Adjusted* | Crude | Adjusted* | Crude | Adjusted†* | |
| Or (95% CI) | Or (95% CI) | Or (95% CI) | Or (95% CI) | Or (95% CI) | Or (95% CI | |
| Employed | ||||||
| Yes | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| No | 1.07 (0.87–1.32) | 1.06 (0.83–1.36) | 1.01 (0.80–1.27) | 0.98 (0.74–1.30) | 1.32 (0.86–2.03) | 1.39 (0.89–2.31) |
| Weekly working hours† | ||||||
| 8–31 (ref) | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| 32–40 | 1.09 (0.83–1.42) | 1.79 (0.42–1.47) | 1.12 (0.83–1.51) | 0.97 (0.71–1.33) | 1.01 (0.56–1.81) | 0.79 (0.42–1.47) |
| >40 | 1.15 (0.67–3.95) | 1.3 (0.8–2.3) | 1.11 (0.61–2.02) | 0.95 (0.51–1.78) | 1.33 (0.45–3.93) | 1.15 (0.37–3.55) |
| Weekly standing/walking hours† | ||||||
| <10 (ref) | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| 10–19 | 1.14 (0.82–1.58) | 1.10 (0.79–1.53) | 1.16 (0.81–1.65) | 1.11 (0.77–1.59) | 1.08 (0.50–2.33) | 1.07 (0.49–2.34) |
| 20–30 | 1.21 (0.81–1.79) | 1.08 (0.72–1.62) | 1.19 (0.77–1.84) | 1.08 (0.69–1.69) | 1.28 (0.52–3.15) | 1.12 (0.45–2.81) |
| >30 | 1.80 (1.19–2.74) | 1.44 (1.01–2.24) | 1.58 (1.00–2.56) | 1.30 (0.78–2.16) | 2.81 (1.25–6.33) | 2.09 (1.00–4.97) |
| Physical work load† | ||||||
| Low (ref) | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| Moderate | 1.23 (0.93–1.61) | 1.11 (0.84–1.48) | 1.11 (0.82–1.50) | 1.01 (0.74–1.39) | 1.89 (1.03–3.48) | 1.66 (0.88–3.13) |
| High | 1.18 (0.78–1.81) | 0.95 (0.60–1.50) | 1.00 (0.61–1.63) | 0.81 (0.48–1.37) | 2.23 (1.01–5.11) | 1.68 (0.67–4.22) |
| Job strain† | ||||||
| Low (ref) | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| Moderate | 1.20 (0.92–1.57) | 1.18 (0.90–1.55) | 1.11 (0.83–1.49) | 1.09 (0.81–1.47) | 1.70 (0.93–3.13) | 1.65 (0.89–3.05) |
| High | 1.14 (0.68–1.93) | 1.02 (0.60–1.76) | 1.04 (0.57–1.88) | 0.96 (0.52–1.77) | 1.71 (0.57–5.11) | 1.37 (0.44–4.27) |
Goodness of fit tests showed no evidence of lack of fit (p>0.0.07 for the three adjusted logistic models).
Bold values indicate statistically significance at the level of p<0.05.
*Model adjusted for: parity, smoking, previous PTB, ethnicity, maternal educational level, maternal age and maternal pre-pregnancy BMI.
†Only employed women included (paid work for at least 8 hours/week, N=4865).
ABCD, Amsterdam Born Children and their Development; BMI, body mass index; PTB, preterm birth.