Characteristics of study children
| Variable | n (%) |
|---|---|
| Mean age at assessment | |
| Initial | 5.8 (SD 2.3) months |
| Range | 2.0–12.0 months |
| Follow-up | 47.4 (SD 4.5) months |
| Range | 3 years 3 months to 4 years |
| 9 months | |
| Mean age difference between assessments | 3.5 (SD 0.4) years |
| Range | 2.6–4.4 years |
| Gender | |
| Male | 91 (70.5) |
| Female | 38 (29.5) |
| Parity | |
| Firstborn | 90 (69.8) |
| Later-born | 39 (30.2) |
| Gestation | |
| <37 weeks | 22 (17.1) |
| Term | 107 (82.9) |
| Multiple birth (missing=5) | |
| Yes | 8 (6.4) |
| No | 116 (93.6) |
| Difficult delivery | |
| Yes | 30 (23.3) |
| No | 99 (76.7) |
| Breastfeeding | |
| Never or <1 month | 34 (26.3) |
| ≥1 month | 95 (73.7) |
| Infant's ethnicity | |
| New Zealand European | 82 (63.6) |
| New Zealand Maori | 14 (10.8) |
| Pacific | 15 (11.6) |
| Asian | 17 (13.2) |
| Other | 1 (0.8) |
| Socioeconomic status | |
| Low (0–40) | 9 (7.0) |
| Medium (41–60) | 58 (45.0) |
| High (>60) | 62 (48.0) |
| Maternal qualifications | |
| Low (none or school certificate) | 23 (17.8) |
| Medium (sixth form or Bursary) | 23 (17.8) |
| High (professional or tertiary qualification) | 83 (64.3) |
| Age plagiocephaly first noticed (weeks) | |
| Mean (SD) | 6.9 (4.7) |
| Range | 0–22.0 |
| Age first seen in clinic | |
| <6 months | 77 (59.7) |
| ≥6 months | 52 (40.3) |
| Neck dysfunction at initial assessment (missing=1) | |
| Yes | 80 (62.5) |
| No | 48 (37.5) |