Table 1. Incidence of schizophrenia in offspring by characteristics of the mother's household during her pregnancy.
| Household characteristics | Number of cases and population | Crude relative risk (RR) | Adjusted relative risk (RR) | ||
|---|---|---|---|---|---|
| RR (95% CI) | p | RR (95% CI) | p | ||
| Crowding (inhabitants per room) | |||||
| 0–0.99 | 9/1174 | 1.00= reference | – | 1.00= reference | – |
| 1–1.99 | 48/4778 | 1.29 (0.63–2.63) | 0.48 | 1.17 (0.57–2.40) | 0.66 |
| 2–2.99 | 22/2655 | 0.98 (0.46–2.15) | 0.98 | 0.83 (0.38–1.82) | 0.64 |
| 3 or more | 25/2304 | 1.28 (0.60–2.74) | 0.52 | 0.91 (0.41–2.03) | 0.82 |
| Number of rooms | |||||
| 1–2 | 57/5961 | 1.00= reference | – | 100=reference | – |
| 3 or more | 47/4950 | 1.11 (0.75–1.63) | 0.60 | 1.04 (0.70–1.53) | 0.86 |
| Number of inhabitants | |||||
| 1–4 | 59/7229 | 1.00= reference | – | 1.00= reference | – |
| 5 or more | 45/3682 | 1.47 (0.99–2.16) | 0.05 | 1.35 (0.74–2.47) | 0.33 |
Adjusted RR—variables adjusted for paternal age (continuous), birth order (continuous), and SES (categorical).