Table 4.
Maternal occupational exposure* to inorganic particles, subdivided into iron particles, stone and concrete particles, and other inorganic particles, and small for gestational age (SGA)†, low birth weight (LBW)‡ and preterm birth (PTB)§
| Working full time with low amount of absence from work¶ | ||||
| Crude | Adjusted** | |||
| OR (95% CI) | n/cases | OR (95% CI) | ||
| Iron particles | ||||
| SGA | ||||
| Unexposed | 1 | 361 282/8916 | 1 | 354 903/8729 |
| Exposed | 1.38 (1.19 to 1.61) | 5361/183 | 1.25 (1.07 to 1.46) | 5253/179 |
| LBW | ||||
| Unexposed | 1 | 356 889/13 362 | 1 | 350 574 /13 109 |
| Exposed | 1.55 (1.38 to 1.75) | 5239/305 | 1.37 (1.22 to 1.54) | 5132/300 |
| PTB | ||||
| Unexposed | 1 | 348 989/21 451 | 1 | 342 797/21 066 |
| Exposed | 1.37 (1.24 to 1.51) | 5119/431 | 1.20 (1.08 to 1.33) | 5016/421 |
| Stone and concrete particles | ||||
| SGA | ||||
| Unexposed | 1 | 358 427/8924 | 1 | 352 060/8735 |
| Exposed | 0.86 (0.74 to 1.00) | 8216/175 | 0.89 (0.76 to 1.04) | 8096/173 |
| LBW | ||||
| Unexposed | 1 | 354 007/13 396 | 1 | 347 700/13 145 |
| Exposed | 0.88 (0.78 to 1.00) | 8121/271 | 0.92 (0.81 to 1.04) | 8006/264 |
| PTB | ||||
| Unexposed | 1 | 346 142/21 450 | 1 | 339 957/21 068 |
| Exposed | 0.88 (0.79 to 0.97) | 7966/432 | 0.91 (0.82 to 1.00) | 7856/419 |
| Other inorganic particles | ||||
| SGA | ||||
| Unexposed | 1 | 366 317/9089 | 1 | 359 836/8898 |
| Exposed | 1.24 (0.66 to 2.32) | 326/10 | 1.07 (0.57 to 2.02) | 320/10 |
| LBW | ||||
| Unexposed | 1 | 361 804/13 655 | 1 | 355 388/13 397 |
| Exposed | 0.98 (0.55 to 1.75) | 324/12 | 0.77 (0.43 to 1.37) | 318/12 |
| PTB | ||||
| Unexposed | 1 | 353 796/21 858 | 1 | 347 507/21 463 |
| Exposed | 1.25 (0.82 to 1.89) | 312/24 | 0.94 (0.62 to 1.43) | 306/24 |
*Exposure divided into unexposed and exposed.
†Small for gestational age, estimated by a calculated growth curve of weight and gestational age.
‡ Low birth weight, dichotomised as <2500 g and ≥2500 g.
§Preterm birth, dichotomised as <37 weeks and ≥37 weeks.
¶Full-time workers who stated that they were working full time at the interview in week 10 and who had fewer than 50 days of absence from work (<50th percentile) during pregnancy (excluding the first 14 days of sickness).
**OR adjusted for the confounders of the mothers’ age, education, smoking habits, nationality, occupational exposure to noise and the children’s parity.