Table 1 Demographic characteristics of the study population at baseline
All POI participants | Those with at least one set of dataa n (%) | Those with at least one set of dataa and DXA at 5 years n (%) | ||
|---|---|---|---|---|
n | 802 | 380 | 257 | |
Maternal variables | ||||
Age at child’s birth (y) | Mean (SD) | 31.6 (5.2) | 32.5 (4.7) | 33.2 (4.4) |
Ethnicity n (%) | New Zealand European | 682 (85.1) | 299 (78.7) | 216 (84.1) |
Māori | 46 (5.7) | 36 (9.5) | 18 (7.0%) | |
Other | 73 (9.1) | 45 (11.8) | 23 (9.0) | |
Missing | 1 | 2 | 0 | |
Parity n (%) | Primiparous | 382 (47.6) | 187 (49.2) | 124 (48.3) |
Multiparous | 420 (52.4) | 193 (50.8) | 133 (51.8) | |
Educationb n (%) | School only | 193 (24.1) | 78 (20.6) | 48 (18.8) |
Post-secondary | 116 (14.6) | 50 (13.2) | 36 (14.1) | |
University degree or higher | 485 (61.1) | 250 (66.1) | 172 (67.2) | |
Missing | 8 | 2 | 1 | |
Pre-pregnancy BMI (kg/m2) | Mean (SD) | 25.1 (5.0) | 25.4 (5.1) | 25.3 (5.2) |
Household or infant variables | ||||
Household deprivationc | 1–3 (Low) | 276 (34.8) | 140 (37.0) | 102 (40.0) |
4–7 | 350 (43.6) | 171 (45.2) | 111 (43.5) | |
8–10 (High) | 168 (21.2) | 67 (17.7) | 42 (16.5) | |
Missing | 8 | 2 | 2 | |
Infant sex | Male | 391 (48.8) | 195 (51.3) | 125 (48.6) |
Female | 411 (51.2) | 185 (48.7) | 132 (51.4) | |
Infant birth weight (kg) | Mean (SD) | 3551 (480) | 3576 (492) | 3581 (496) |