Adjusted associations between gestational age (cases = 834; controls = 20 100), and birth weight at term (cases = 763; controls = 17 625), and the risk of hyperkinetic disorder
| Controls n = 20 100 | Cases n = 834 | Adjusted RR (95% CI) | Controls† n = 10 253 | Cases† n = 460 | Adjusted* RR (95% CI) | |
|---|---|---|---|---|---|---|
| Results presented as rate ratios (RR) with 95% confidence intervals (CI) from a conditional logistic regression model. | ||||||
| *p<0.05. | ||||||
| †Cases and controls are matched for age, sex, and date of birth and adjusted for parental socioeconomic data and parental age. Excluded are children of parents with history of mental disorders (141 cases and their controls), children with hyperkinetic conduct disorder (F90.10) as main and 1st and 2nd subsidiary diagnosis, and other comorbid disorders except for specific developmental disorders (F800–F893) (233 cases and their controls). | ||||||
| Gestational age (wk) | ||||||
| <34 | 298 | 34 | 2.7 (1.8–4.1) | 152 | 20 | 3.3 (2.0–5.4) |
| 34–36 | 544 | 37 | 1.7 (1.2–2.5) | 270 | 19 | 1.6 (0.99–2.5) |
| 37–39 | 6629 | 298 | 1.1 (0.9–1.3) | 3321 | 166 | 1.2 (1.0–1.5)* |
| 40–42 | 12365 | 456 | 1 | 6378 | 251 | 1 |
| 43–44 | 264 | 9 | 1.0 (0.5–2.0) | 132 | 4 | 0.7 (0.3–2.2) |
| Children born at 37 completed weeks of gestation or more | Controls n = 17 625 | Cases n = 763 | Controls† n = 8994 | Cases† n = 421 | ||
| Birth weight at term (g) | ||||||
| <1500 | 1 | 0 | – | 1 | 0 | – |
| 1500–2499 | 288 | 27 | 1.9 (1.2–2.9) | 131 | 12 | 1.7 (0.9–3.2) |
| 2500–2999 | 1888 | 127 | 1.5 (1.2–1.8) | 946 | 75 | 1.7 (1.3–2.3) |
| 3000–3999 | 12099 | 478 | 1 | 6204 | 269 | 1 |
| 4000–5990 | 3349 | 131 | 1.0 (0.9–1.3) | 1713 | 65 | 0.9 (0.7–1.2) |