Table 2 Hospital admission due to isolated TBI among siblings according to birth order
|  | 1987–1992 | 1993–1998 | 1999–2005 | 1987–2005 | ||||
|---|---|---|---|---|---|---|---|---|
Birth order | ≤ 2 days Frequency (%) | >  2 days Frequency (%) | ≤ 2 days Frequency (%) | >  2 days Frequency (%) | ≤ 2 days Frequency (%) | >  2 days Frequency (%) | ≤ 2 days Frequency (%) | >  2 days Frequency (%) |
First | 70 (85.4%) | 12 (14.6%) | 140 (81.4%) | 32 (18.6%) | 334 (93.0%) | 25 (7.0%) | 544 (88.7%) | 69 (11.3%) |
Second | 92 (88.5%) | 12 (11.5%) | 147 (87.5%) | 21 (12.5%) | 276 (93.9%) | 18 (6.1%) | 515 (91.0%) | 51 (9.0%) |
Third | 39 (83.0%) | 8 (17.0%) | 63 (81.8%) | 14 (18.2%) | 147 (95.5%) | 7 (4.5%) | 249 (89.6%) | 29 (10.4%) |
Fourth or higher | 24 (77.4%) | 7 (22.6%) | 38 (80.9%) | 9 (19.1%) | 75 (94.9%) | 4 (5.1%) | 137 (87.3%) | 20 (12.7%) |