Table 2. The Birth and the Sociodemographic Characteristics of the Study Sample by Parity Status.
| Parity | |||
| Characteristic | 1–5 (n = 12902) | 6 or more (n = 341) | |
| Mean (SDa)/N (%) | Mean (SDa)/N (%) | p | |
| Maternal Age at Childbirth | 28.2 (5.3) | 36.2 (4.7) | <0.001 |
| Categorical: | <0.001 | ||
| <20 years | 338 (2.6%) | 0 (0%) | |
| 20 to 29 years | 7626 (59.1%) | 28 (8.2%) | |
| 30 to 39 years | 4622 (35.8%) | 223 (65.4%) | |
| ≥40 years | 316 (2.4%) | 90 (26.4%) | |
| Birth Weight (Grams) | 3399.4 (475.7) | 3694.3 (513.1) | <0.001 |
| Maternal Body Mass Index (kg/m2) | 26.2 (2.8) | 27.6 (3.6) | <0.001 |
| Fathers’ Occupational Status in Childhood | |||
| Manual Worker | 7293 (56.5%) | 254 (74.5%) | <0.001 |
| Clerical Worker | 5264 (40.8%) | 85 (24.9%) | |
| Unknown | 345 (2.7%) | 2 (0.6%) | |
| Mothers’ Occupational Status in Childhood | |||
| Manual Worker | 6592 (51.1%) | 211 (61.9%) | <0.001 |
| Clerical Worker | 4942 (38.3%) | 56 (16.4%) | |
| Other or Unknown | 1368 (10.6%) | 74 (21.7%) | |
| Year of Birth | |||
| 1934–1938 | 2930 (22.7%) | 99 (29.0%) | 0.01 |
| 1939–1944 | 9972 (77.3%) | 242 (71.0%) | |
| Sex | |||
| Women | 6177 (47.9%) | 161 (47.2%) | 0.81 |
| Men | 6725 (52.1%) | 180 (52.8%) | |
a
SD = Standard Deviation.