Table 2. Odds ratios and 95% CIs for all childhood brain tumours in relation to trimester of ultrasound exposure.
|
Crude
|
Adjusteda
|
||||||
|---|---|---|---|---|---|---|---|
| Cases | Controls | OR | 95% CI | OR | 95% CI | ||
| Unexposedb | 283 | 280 | 1.00 | 1.00 | |||
| First trimester (weeks 2–14) | Only first | 12 | 17 | 0.70 | 0.33–1.49 | 0.75 | 0.34–1.63 |
| First and otherc | 24 | 28 | 0.85 | 0.48–1.50 | 0.96 | 0.53–1.73 | |
| Second trimester (weeks 15–28) | Only second | 64 | 62 | 1.02 | 0.69–1.50 | 1.05 | 0.70–1.56 |
| Second and otherc | 70 | 62 | 1.12 | 0.76–1.63 | 1.27 | 0.85–1.90 | |
| Third trimester (weeks 29–45) | Only third | 53 | 69 | 0.76 | 0.51–1.13 | 0.82 | 0.54–1.24 |
| Third and otherc | 65 | 67 | 0.96 | 0.66–1.40 | 1.10 | 0.74–1.65 | |
Abbreviations: CI=confidence interval; OR=odds ratio.
Only subjects with information on all variables adjusted for are included. Thirty subjects with uncertain trimester of ultrasound exposure were excluded.
a
Adjusted for maternal age, parity, multiple birth, mother born in a Nordic country, gestational age at birth, mode of delivery, breech position, birth weight, head circumference at birth, level of hospital, hypertension during pregnancy and maternal smoking.
b
Reference group.
c
Individuals were also exposed to ultrasound in at least one of the other trimester. Consequently, one individual can be included in more than one of the ‘other’ row.