Table 1.
Demographic characteristics of the samples analysed
| Epidemiology sample (CSHQ and blood data available, n = 395) | RCT sample (n = 362) | Actigraphy sample (n = 43) | CSHQ caseness* subgroup of RCT (n = 188) | |
|---|---|---|---|---|
| Sex, n (%) | ||||
| Female | 177 (44.81) | 170 (46.96) | 21 (48.84) | 99 (52.38) |
| Male | 218 (55.19) | 192 (53.04) | 22 (51.16) | 89 (47.09) |
| Age in years, n (%) | ||||
| 6/7 years | 111 (28.1) | 80 (22.1) | 9 (20.93) | 39 (20.63) |
| 8 years | 143 (36.2) | 137 (37.85) | 18 (41.86) | 69 (36.51) |
| 9/10 years | 141 (35.7) | 145 (40.06) | 16 (37.21) | 80 (42.33) |
| Weight, kg | ||||
| Mean (SD) | 30.72 kg (7.68) | 30.86 kg (7.54) | 33.12 kg (8.24) | 30.72 kg (7.48) |
| Free school meals, n (%) | ||||
| Not eligible | 347 (87.85) | 289 (79.83) | 32 (74.42) | 138 (73.02) |
| Eligible | 48 (12.15) | 73 (20.17) | 11 (25.58) | 50 (26.46) |
| Ethnicity, n (%) | ||||
| White | 362 (91.65) | 330 (91.16) | 41 (95.35) | 171 (90.48) |
| Mixed | 12 (3.04) | 16 (4.42) | 1 (2.33) | 8 (4.23) |
| Asian | 6 (1.52) | 2 (0.55) | 0 (0) | 2 (1.06) |
| Black | 1 (0.25) | 1 (0.28) | 0 (0) | 1 (0.53) |
| Other | 5 (1.27) | 7 (1.93) | 1 (2.33) | 3 (1.59) |
| Missing information | 9 (2.28) | 6 (1.8) | 0 (0) | 3 (1.59) |
RCT, randomized clinical trial; SD, standard deviation; CSHQ, Child Sleep Habits Questionnaire.
*
‘Caseness’: clinical level sleep problems as indicated by total CSHQ score >41.