Table 2. Descriptive statistics for the birth and cognitive variables (unimputed).
| Variable | Dementia sample | Cognitive impairment sample | ||||
|---|---|---|---|---|---|---|
| All | Males | Females | All | Males | Females | |
| N | 34,166–35,191 | 16,324–16,813 | 17,842–18,378 | 3,727–4,000 | 1,744–1,876 | 1,983–2,124 |
| BW (100 g) | 2,664 (505.7) | 2,727 (506.8) | 2,607 (497.9) | 2,678 (508.5) | 2,747 (505.6) | 2,618 (503.5) |
| LBW | 12,752 (36.2%) | 5,335 (31.7%) | 7,417 (40.4%) | 1,566 (39.2%) | 629 (33.5%) | 938 (44.2%) |
| SGA* | 801 (2.4%) | 372 (2.3%) | 429 (2.4%) | 83 (2.7%) | 49 (2.8%) | 51 (2.6%) |
| HC (mm) | 329.5 (17.5) | 332.6 (17.1) | 326.7 (17.4) | 332.3 (16.8) | 335.7 (16.2) | 329.3 (16.8) |
| SHCGA* | 920 (2.8%) | 420 (2.7%) | 500 (2.9%) | 107 (3.1%) | 51 (3.1%) | 56 (3.1%) |
| BL (cm) | 47.7 (2.8) | 48.1 (2.7) | 47.3 (2.8) | 47.9 (2.7) | 48.3 (2.7) | 47.5 (2.7) |
| SBLGA* | 988 (2.9%) | 454 (2.8%) | 530 (3.0%) | 105 (2.9%) | 40 (2.3%) | 62 (3.2%) |
| GA (weeks) | 37.8 (2.5) | 37.7 (2.5) | 37.8 (2.5) | 37.8 (2.4) | 37.8 (2.5) | 37.9 (2.4) |
| Preterm | 9,559 (28.4%) | 4,661 (29.0%) | 4,898 (27.8%) | 1,020 (27.6%) | 481 (27.6%) | 539 (27.5%) |
| Dementia | 907 (2.6%) | 415 (2.5%) | 492 (2.7%) | 471 (11.8%) | 209 (11.1%) | 262 (12.3%) |
| Age at diagnosis (years) | 74.3 (2.6) | 73.8 (7.4) | 74.8 (7.4) | 78.7 (5.0) | 78.4 (5.2) | 79.0 (4.9) |
| Cognitive impairment | — | — | — | 569 (14.2%) | 270 (14.4%) | 299 (14.1%) |
| Age at screening (years) | — | — | — | 68.4 (2.6) | 68.4 (2.5) | 68.3 (2.6) |
Data are given as mean (SD) or count (percent).
*As GA was not available for everyone, the Ns for the GA-corrected variables are somewhat reduced in the total sample (N = 32,754–33,702) and in the subsample (N = 3,454–3,702).
BL, birth length; BW, birth weight; GA, gestational age; HC, head circumference; LBW, low birth weight; SBLGA, short birth length for gestational age; SGA, small for gestational age; SHCGA, small head circumference for gestational age.