Odds ratios of total and selected birth defects by maternal occupational exposure to magnetic fields above 0.1 μT in Norway 1967–95
| Crude | Adjusted† | |||||||
|---|---|---|---|---|---|---|---|---|
| Category of birth defects | Hours exposed/week | Cases (n) | OR | 95% CI | p Value* | OR | 95% CI | p Value* |
| *Test for trend across three exposure categories; †adjusted for highest family educational level, place of birth, mothers age, and year of birth; ‡refers to the ICD-8 category 758. | ||||||||
| Any birth defect | <4 | 22066 | 1.00 | 0.47 | 1.00 | 0.13 | ||
| 4–24 | 1703 | 1.02 | 0.97 to 1.08 | 1.06 | 1.01 to 1.12 | |||
| >24 | 119 | 0.76 | 0.64 to 0.92 | 0.92 | 0.77 to 1.11 | |||
| All CNS defects | <4 | 1158 | 1.00 | 0.12 | 1.00 | 0.36 | ||
| 4–24 | 95 | 1.09 | 0.88 to 1.34 | 1.03 | 0.84 to 1.28 | |||
| >24 | 13 | 1.60 | 0.93 to 2.77 | 1.41 | 0.81 to 2.44 | |||
| Anencephaly | <4 | 306 | 1.00 | 0.96 | 1.00 | 0.55 | ||
| 4–24 | 21 | 0.91 | 0.58 to 1.42 | 0.82 | 0.53 to 1.29 | |||
| >24 | 3 | 1.40 | 0.45 to 4.36 | 1.11 | 0.35 to 3.48 | |||
| Spina bifida | <4 | 402 | 1.00 | 0.02 | 1.00 | 0.04 | ||
| 4–24 | 38 | 1.25 | 0.90 to 1.75 | 1.21 | 0.86 to 1.69 | |||
| >24 | 7 | 2.48 | 1.18 to 5.25 | 2.33 | 1.10 to 4.94 | |||
| Hydrocephaly | <4 | 310 | 1.00 | 0.18 | 1.00 | 0.13 | ||
| 4–24 | 20 | 0.86 | 0.54 to 1.35 | 0.82 | 0.52 to 1.30 | |||
| >24 | 0 | 0.03 | 1 | 0.03 | ||||
| Other CNS defects | <4 | 147 | 1.00 | 0.03 | 1.00 | 0.05 | ||
| 4–24 | 16 | 1.44 | 0.86 to 2.42 | 1.44 | 0.86 to 2.43 | |||
| >24 | 3 | 2.91 | 0.93 to 9.13 | 2.55 | 0.81 to 8.06 | |||
| Cardiac defects | <4 | 1744 | 1.00 | 0.03 | 1.00 | 0.33 | ||
| 4–24 | 118 | 0.90 | 0.74 to 1.08 | 1.00 | 0.83 to 1.21 | |||
| >24 | 4 | 0.33 | 0.12 to 0.87 | 0.40 | 0.15 to 1.05 | |||
| Respiratory system defects | <4 | 490 | 1.00 | 0.02 | 1.00 | 0.05 | ||
| 4–24 | 24 | 0.65 | 0.43 to 0.98 | 0.90 | 0.59 to 1.36 | |||
| >24 | 1 | 0.30 | 0.04 to 2.07 | 0.50 | 0.07 to 3.59 | |||
| Isolated cleft palate | <4 | 397 | 1.00 | 0.01 | 1.00 | 0.01 | ||
| 4–24 | 17 | 0.57 | 0.35 to 0.93 | 0.57 | 0.35 to 0.92 | |||
| >24 | 1 | 0.37 | 0.05 to 2.56 | 0.34 | 0.05 to 2.34 | |||
| Total cleft lip | <4 | 1042 | 1.00 | 0.10 | 1.00 | 0.12 | ||
| 4–24 | 85 | 1.08 | 0.87 to 1.35 | 1.07 | 0.86 to 1.34 | |||
| >24 | 13 | 1.78 | 1.03 to 3.08 | 1.73 | 1.00 to 2.99 | |||
| Genital system defects | <4 | 3208 | 1.00 | 0.56 | 1.00 | 0.19 | ||
| 4–24 | 273 | 1.13 | 1.00 to 1.28 | 1.15 | 1.02 to 1.31 | |||
| >24 | 13 | 0.58 | 0.34 to 1.00 | 0.71 | 0.41 to 1.22 | |||
| Clubfoot | <4 | 5051 | 1.00 | 0.02 | 1.00 | 0.04 | ||
| 4–24 | 460 | 1.21 | 1.10 to 1.33 | 1.13 | 1.03 to 1.25 | |||
| >24 | 24 | 0.68 | 0.45 to 1.01 | 0.92 | 0.62 to 1.38 | |||
| Other defects‡ | <4 | 58 | 1.00 | 0.63 | 1.00 | 0.45 | ||
| 4–24 | 4 | 0.91 | 0.33 to 2.52 | 0.76 | 0.27 to 2.11 | |||
| >24 | 0 | 0.07 | 0.03 | |||||
| Down's syndrome | <4 | 871 | 1.00 | 0.02 | 1.00 | 0.29 | ||
| 4–24 | 51 | 0.78 | 0.59 to 1.03 | 0.93 | 0.70 to 1.24 | |||
| >24 | 2 | 0.33 | 0.08 to 1.31 | 0.43 | 0.11 to 1.70 | |||