Multivariable-adjusted logistic regression for the association between maternal occupational exposure to whole-body vibrations and pregnancy complications among full-time working women who gave birth to singleton children in Sweden between 1994 and 2014 (n=710 391)
| Whole-body vibration exposure (m/s2) | Full-time workers | |||
| Crude OR (95% CI) | Adjusted* OR (95% CI) | |||
| Preeclampsia | n (%) cases | n=710 391 | n (%) cases | n=646 490 |
| 0 | 23 435 (3.3) | 1.00 | 21 324 (3.4) | 1.00 |
| 0.1–0.2 | 394 (3.4) | 1.01 (0.91 to 1.12) | 348 (3.3) | 0.95 (0.84 to 1.07) |
| 0.3–0.4 | 93 (4.0) | 1.20 (0.98 to 1.48) | 77 (4.3) | 1.20 (0.95 to 1.52) |
| ≥0.5 | 100 (5.7) | 1.75 (1.34 to 2.14) | 97 (5.9) | 1.76 (1.41 to 2.20) |
| Gestational hypertension† | n=706 448 | n=642 999 | ||
| 0 | 30 139 (4.4) | 1.00 | 27 506 (4.4) | 1.00 |
| 0.1–0.2 | 501 (4.3) | 1.00 (0.91 to 1.09) | 450 (4.3) | 0.94 (0.85 to 1.04) |
| 0.3–0.4 | 110 (4.8) | 1.11 (0.91 to 1.34) | 91 (5.1) | 1.08 (0.87 to 1.34) |
| ≥0.5 | 115 (6.7) | 1.55 (1.28 to 1.88) | 111 (6.8) | 1.55 (1.26 to 1.91) |
| Gestational diabetes | n=707 418 | n=643 726 | ||
| 0 | 6061 (0.9) | 1.00 | 5417 (0.9) | 1.00 |
| 0.1–0.2 | 96 (0.8) | 0.95 (0.77 to 1.16) | 90 (0.9) | 0.92 (0.73 to 1.15) |
| 0.3–0.4 | 18 (0.8) | 0.89 (0.56 to 1.42) | 14 (0.8) | 0.66 (0.39 to 1.14) |
| ≥0.5 | 28 (1.6) | 1.86 (1.28 to 2.70) | 26 (1.6) | 1.62 (1.07 to 2.46) |
*Adjustments: maternal body mass index (<18.5, 18.5–24.9, 25–29.9, ≥30 kg/m2), age (years), parity (birth order of the child), smoking habits (non-smoking, 1–9, ≥10 cigarettes/day), education (4 groups based on highest degree: ≤elementary, high-school, higher education <3 years, higher education ≥3 years), nationality (Swedish, European, Other, Unknown/missing), calendar year, exposure to noise (5 categories:<70, 70–74, 75–79, 80–84, ≥85 dB), combustion particles (yes/no), job strain (four groups: low demands and high control, high demands and low control, low demands and high control, and high demands and high control) and physically strenuous work (average of indices ranging from 1 to 6).
†Includes both gestational hypertension and preeclampsia diagnosis. Excluding women with hypertension before pregnancy (International Classification of Diseases (ICD)-9 codes 642 and 642A-D and ICD-10 codes O13, O13.9, O16 and O16.9).
‡Excluding women with type 1 or type 2 diabetes before pregnancy (ICD-9 250, E10–E14, 648A and O24.0–24.3).