Table 3.
Odds ratios (95% confidence intervals) for incidence of schizophrenia in relation to prenatal and perinatal characteristics for male and female subjects. Values derived from conditional logistic regression model
| Male subjects (n=106) | Female subjects (n=57) | |
|---|---|---|
| Maternal factors | ||
| Age at delivery (years): | ||
| ⩽19 | 0.7 (0.3 to 2.0) | 0.9 (0.3 to 2.9) |
| 20-29* | 1.0 | 1.0 |
| ⩾30 | 1.5 (0.9 to 2.5) | 1.1 (0.5 to 2.3) |
| Parity: | ||
| 1 | 1.4 (0.9 to 2.3) | 1.2 (0.6 to 2.2) |
| 2-3* | 1.0 | 1.0 |
| 4 | 3.6 (1.6 to 7.8)† | 0.5 (0.1 to 2.5)† |
| Pregnancy and delivery factors | ||
| Hypertensive diseases | 1.6 (0.6 to 4.3) | 0.7 (0.1 to 6.2) |
| Diabetes | No exposure | 13.5 (0.8 to 239.4) |
| Bleeding during pregnancy | 4.0 (1.1 to 13.7) | 4.4 (0.3 to 65.2) |
| Uterine atony | 1.3 (0.6 to 2.9) | 1.3 (0.3 to 4.1) |
| Child characteristics | ||
| Birth weight for gestational age: | ||
| Small (⩾2 SD below mean) | 3.2 (1.4 to 7.2)† | 0.3 (0.03 to 2.4)† |
| Mean* | 1.0 | 1.0 |
| Large (⩾2 SD above mean) | 0.6 (0.2 to 2.4) | 0.3 (0.03 to 3.3) |
| Ponderal index (centiles)‡: | ||
| ⩽5 | 3.1 (1.4 to 7.1) | 0.5 (0.1 to 5.1) |
| 6-94* | 1.0 | 1.0 |
| ⩾95 | 0.5 (0.2 to 2.0) | 1.5 (0.5 to 4.3) |
| Apgar score at 1 minute: | ||
| 0-6 | 1.4 (0.5 to 4.1) | 0.6 (0.1 to 2.8) |
| 7-10* | 1.0 | 1.0 |
| Asphyxia | 0.8 (0.4 to 1.7) | 1.6 (0.5 to 4.9) |
| Season of birth | ||
| January-April | 1.4 (0.9 to 2.3) | 1.6 (0.9 to 2.8) |
| May-December* | 1.0 | 1.0 |
*
Reference category.
†
Significant interaction with sex (P<0.05).
‡
(100×(birth weight (g))/(birth length (cm))3. Entered in a separate model in place of birth weight for gestational age.