TABLE 5.
Associations Between CP in 1 Sibling and Neurodevelopmental Disorders in Other Siblings
| Exposure–Outcome | Sibship | Cases/Exposed Younger Sibs | Cases/Unexposed Younger Sibs | Crude OR (95% CI) | Adjusted ORa (95% CI) | OR Combinedb (95% CI) | P for Heterogeneity |
|---|---|---|---|---|---|---|---|
| CP–CP | Singletons | 33/2180 | 2734/1 320 235 | 7.4 (5.2–10.5) | 7.3 (4.9–11.0) | ||
| CP–CP | 33/2767 | 2147/1 319 648 | 7.4 (5.2–10.5) | 7.3 (4.9–11.0) | 7.3 (5.5–9.7) | >0.9 | |
| CP–CP | Twins | 3/64 | 66/19 994 | 14.8 (4.5–49) | 15.3 (4.7–50) | ||
| CP–CP | 3/69 | 61/19 989 | 14.8 (4.5–49) | 15.3 (4.7–50) | 15.3 (6.7–35) | >0.9 | |
| CP–epilepsy | Singletons | 28/2180 | 10 931/1 320 235 | 1.6 (1.1–2.3) | 1.6 (1.1–2.3) | ||
| Epilepsy–CP | 44/10 486 | 2723/1 311 929 | 2.0 (1.5–2.7) | 2.0 (1.5–2.7) | 1.8 (1.4–2.3) | 0.3 | |
| CP–epilepsy | Twins | 1/64 | 149/19 994 | 2.1 (0.3–15.3) | 2.0 (0.3–14.7) | ||
| Epilepsy–CP | 0/187 | 69/19 871 | — | — | — | ||
| CP–intellectual disability | Singletons | 32/2180 | 7456/1 320 235 | 2.6 (1.8–3.7) | 2.7 (1.8–3.9) | ||
| Intellectual disability–CP | 34/6879 | 2733/1 315 536 | 2.4 (1.7–3.3) | 2.4 (1.7–3.3) | 2.5 (2.0–3.2) | 0.6 | |
| CP–intellectual disability | Twins | 1/64 | 137/19 994 | 2.3 (0.3–16.7) | 2.2 (0.3–16.1) | ||
| Intellectual disability–CP | 1/111 | 68/19 947 | 2.7 (0.4–19.3) | 2.7 (0.4–19.1) | 2.4 (0.6–9.8) | 0.9 | |
| CP–ADHD | Singletons | 51/2180 | 19 995/1 320 235 | 1.6 (1.2–2.1) | 1.5 (1.1–2.0) | ||
| ADHD–CP | 50/19 005 | 2717/1 303 410 | 1.3 (0.95–1.7) | 1.2 (0.9–1.6) | 1.4 (1.1–1.7) | 0.3 | |
| CP–ADHD | Twins | 4/64 | 329/19 994 | 4.0 (1.4–11.0) | 3.5 (1.3–9.7) | ||
| ADHD–CP | 1/336 | 68/19 722 | 0.9 (0.1–6.2) | 0.9 (0.1–6.2) | 2.3 (0.7–8.1) | 0.2 | |
| CP–autism spectrum disorder | Singletons | 11/2180 | 4969/1 320 235 | 1.3 (0.7–2.4) | 1.3 (0.7–2.4) | ||
| Autism spectrum disorder–CP | 18/5175 | 2749/1 317 240 | 1.7 (1.05–2.7) | 1.6 (1.01–2.5) | 1.5 (1.01–2.1) | 0.6 | |
| CP–autism spectrum disorder | Twins | 0/64 | 94/19 994 | — | — | ||
| Autism spectrum disorder–CP | 0/85 | 69/19 973 | — | — | — | ||
| CP–deafness | Singletons | 22/2180 | 9682/1 320 235 | 1.4 (0.9–2.1) | 1.4 (0.9–2.2) | ||
| Deafness–CP | 21/8810 | 2746/1 313 605 | 1.1 (0.7–1.8) | 1.2 (0.8–1.8) | 1.3 (0.9–1.7) | 0.6 | |
| CP–deafness | Twins | 1/64 | 143/19 994 | 2.2 (0.3–16.0) | 2.3 (0.3–16.8) | ||
| Deafness–CP | 0/125 | 69/19 933 | — | — | — | ||
| CP–blindness | Singletons | 4/2180 | 711/1 320 235 | 3.4 (1.3–9.1) | 3.4 (1.3–9.0) | ||
| Blindness–CP | 0/625 | 2767/1 321 790 | — | — | — | ||
| CP–blindness | Twins | 0/64 | 17/19 994 | — | — | ||
| Blindness–CP | 1/8 | 68/20 050 | 42 (5–346) | 44 (6–347) | — | ||
| CP–schizophrenia | Singletonsc | 3/1077 | 2656/732 204 | 0.8 (0.3–2.4) | 0.8 (0.3–2.4) | ||
| Schizophrenia–CP | 13/2808 | 1412/730 473 | 2.4 (1.4–4.2) | 2.4 (1.4–4.1) | 1.5 (0.5–4.6) | 0.07 | |
| CP–schizophrenia | Twinsd | 1/31 | 40/9841 | 8.2 (1.1–61.4) | 8.5 (1.2–62.4) | ||
| Schizophrenia–CP | 0/47 | 31/9825 | — | — | — | ||
| CP–bipolar disorder | Singletonsc | 4/1077 | 4169/732 204 | 0.7 (0.2–1.7) | 0.7 (0.2–1.7) | ||
| Bipolar disorder–CP | 10/4522 | 1415/728 759 | 1.1 (0.6–2.1) | 1.1 (0.6–2.1) | 1.0 (0.6–1.7) | 0.3 | |
| CP–bipolar disorder | Twinsd | 0/31 | 53/9841 | — | — | ||
| Bipolar disorder–CP | 0/60 | 31/9812 | — | — | — | ||
| CP–stillbirth | Singletons | 15/2206 | 7762/1 345 059 | 1.2 (0.7–2.0) | 1.2 (0.7–2.0) | ||
| Stillbirth–CP | 24/7471 | 2783/1 339 794 | 1.5 (1.04–2.3) | 1.6 (1.04–2.5) | 1.4 (1.03–2.0) | 0.4 | |
| CP–stillbirth | Twins | 5/71 | 188/20 542 | 8.2 (3.3–21) | 9.3 (3.6–24) | ||
| Stillbirth–CP | 4/218 | 70/20 395 | 5.4 (2.0–15) | 5.9 (2.0–17) | 7.6 (3.8–15.5) | 0.5 | |
| CP–neonatal deathe | Singletons | 11/2206 | 4731/1 345 059 | 1.4 (0.8–2.6) | 1.5 (0.8–2.7) | ||
| Neonatal death–CP | 16/5227 | 2791/1 342 038 | 1.5 (0.9–2.4) | 1.5 (0.9–2.5) | 1.5 (1.03–2.2) | >0.9 | |
| CP–neonatal death | Twins | 2/71 | 108/20 542 | 5.5 (1.3–23) | 5.6 (1.3–24) | ||
| Neonatal death–CP | 1/119 | 73/20 494 | 2.4 (0.3–17) | 2.4 (0.3–18) | 4.3 (1.3–13.5) | 0.5 | |
| CP–late neonatal deathf | Singletons | 7/2206 | 3598/1 345 059 | 1.2 (0.6–2.5) | 1.2 (0.6–2.6) | ||
| Late neonatal death–CP | 13/5615 | 2794/1 341 650 | 1.1 (0.6–1.9) | 1.1 (0.7–1.9) | 1.2 (0.8–1.8) | 0.8 | |
| CP–late neonatal death | Twins | 2/71 | 75/20 542 | 7.9 (1.9–33) | 7.8 (1.8–33) | ||
| Late neonatal death–CP | 0/81 | 74/20 532 | — | — | — |
1 322 415 pairs of singleton full sibling neonatal survivors (survived >28 days) and 20 058 pairs of twins neonatal survivors. Associations between CP in 1 sibling and early death in other siblings. 1 347 265 pairs of singleton full siblings and 20 613 pairs of twins. Older sibling born term (gestational age ≥37 completed weeks for singletons and 36 for Twins. Norway, 1967 to 2006. —, indicates it was not possible to calulate ORs due to zero cases.
a
Adjusted for older sibling’s (or twins’) year of birth in 5-year categories (eg, 1967–1971, 1972–1976).
b
Adjusted ORs combined with meta-analyses.
c
A total of 733 281 pairs of singleton full sibs born between 1967 and 1990.
d
A total of 9872 pairs of twins born between 1967 and 1990.
e
Death from 0 to 28 days.
f
Death from 29 days to 1 year.