Table 1. Baseline Characteristics of Study Cohorta.
| Characteristic | Study group, No. (%) of participants (n = 53 444) | SMD | |
|---|---|---|---|
| Patients (n = 3408) | Controls (n = 50 036) | ||
| Sex | |||
| Male | 2305 (67.6) | 33 861 (67.7) | <0.001 |
| Female | 1103 (32.4) | 16 175 (32.3) | |
| Gestational age, wk | |||
| <37 | 458 (14.6) | 2596 (5.7) | 0.30 |
| 37-41 | 2475 (79.0) | 39 097 (86.1) | |
| ≥42 | 199 (6.4) | 3721 (8.2) | |
| Birth length SDSb | |||
| SGA (<–2) | 1075 (35.1) | 3263 (7.3) | 0.76 |
| AGA (–2 to <2) | 1969 (64.3) | 39 643 (88.3) | |
| LGA (≥2) | 18 (0.6) | 1966 (4.4) | |
| Birth weight SDSb | |||
| SGA (<–2) | 662 (21.2) | 1884 (4.2) | 0.55 |
| AGA (–2 to <2) | 2441 (78.2) | 42 299 (93.5) | |
| LGA (≥2) | 19 (0.6) | 1062 (2.3) | |
| Age at study start, y | |||
| 0-4 | 369 (10.8) | 5517 (11.0) | 0.02 |
| 5-9 | 1501 (44.0) | 21 750 (43.5) | |
| 10-14 | 1433 (42.0) | 21 109 (42.2) | |
| ≥15 | 105 (3.1) | 1660 (3.3) | |
| Height at study start, cm | |||
| <100 | 446 (13.8) | 1195 (2.5) | 0.93 |
| 100-149 | 2698 (83.6) | 30 984 (64.8) | |
| ≥150 | 84 (2.6) | 15 600 (32.7) | |
| Family income levelc | |||
| 1 | 627 (18.5) | 9942 (20.0) | 0.07 |
| 2 | 638 (18.8) | 9816 (19.7) | |
| 3 | 679 (20.0) | 9963 (20.0) | |
| 4 | 660 (19.4) | 10 013 (20.1) | |
| 5 | 792 (23.3) | 10 051 (20.2) | |
| Parental educational leveld | |||
| 1 | 50 (1.5) | 929 (1.9) | 0.06 |
| 2 | 149 (4.4) | 2077 (4.2) | |
| 3 | 864 (25.4) | 13 228 (26.5) | |
| 4 | 600 (17.6) | 9274 (18.6) | |
| 5 | 576 (16.9) | 8872 (17.8) | |
| 6 | 1059 (31.1) | 14 229 (28.5) | |
| 7 | 108 (3.2) | 1273 (2.6) | |
Abbreviations: AGA, appropriate for gestational age; LGA, large for gestational age; SDS, standard deviation score; SGA, small for gestational age; SMD, standardized mean difference.
Percentages have been rounded and may not total 100. Percentage of missing values for each baseline characteristic is given in eTable 4 in the Supplement.
Reference for calculation is given in the eMethods in the Supplement.
For quintiles of total disposable income within the family household at study inclusion, 1 indicates lowest and 5 the highest family income quintiles.
Reported as highest achievable educational level for parents collected from the Swedish Register of Education; 1 indicates primary school less than 9 years; 2, primary school for 9 years; 3, secondary school for 2 years or less; 4, secondary school for more than 2 years; 5, higher education of less than 3 years; 6, higher education of 3 or more years; and 7, postgraduate/doctoral studies.