Table 4 Sample characteristics at baseline by trajectory group membership (n = 12,536)
| Â | Low declining (498) | Low improving (979) | Average (7573) | High (3486) | Total | p value |
|---|---|---|---|---|---|---|
Short stature age 3 years % | 8.4 | 5.8 | 4.2 | 2.8 | 4.1 |  < 0.001 |
Sex (girls) % | 44.2 | 40.6 | 49.3 | 52.8 | 49.4 |  < 0.001 |
Ethnicity (White) % | 80.9 | 50.5 | 86.4 | 93.4 | 85.3 |  < 0.001 |
Birth weight in kg (SD) | 3.3 (0.7) | 3.2 (0.6) | 3.4 (0.6) | 3.4 (0.5) | 3.4 (0.6) |  < 0.001 |
Mid-parental height (SD) |  − 0.1 (0.8) |  − 0.2 (0.8) | 0.0 (0.8) | 0.1 (0.8) | 0.0 (0.8) |  < 0.001 |
Mother’s age, years (SD) | 27.9 (6.2) | 27.9 (6.0) | 29.2 (5.9) | 31.1 (5.2) | 29.6 (5.8) |  < 0.001 |
Mother has A level or higher % | 22.9 | 25.7 | 46.3 | 68.7 | 50.0 |  < 0.001 |
Second-hand smoke exposure % | 27.9 | 19.1 | 13.9 | 6.6 | 12.8 |  < 0.001 |
Breastfeeding % | 55.0 | 65.8 | 66.6 | 80.5 | 69.9 |  < 0.001 |
Mother’s diagnosis of depression or anxiety | 29.7 | 22.0 | 25.9 | 20.8 | 24.3 |  < 0.001 |
Income quintiles % | ||||||
 Lowest | 40.4 | 45.5 | 22.3 | 8.5 | 21.0 |  < 0.001 |
 Second | 30.5 | 32.9 | 23.7 | 12.7 | 21.6 |  |
 Third | 15.3 | 11.0 | 21.2 | 19.4 | 19.7 |  |
 Fourth | 9.6 | 6.5 | 18.3 | 27.4 | 19.5 |  |
 Highest | 4.2 | 4.1 | 14.6 | 32.0 | 18.2 |  |
IMD average (SD) | 3.5 (2.6) | 2.9 (2.2) | 4.7 (2.9) | 5.9 (2.8) | 4.8 (2.9) |  < 0.001 |