TABLE 1

Demographic Characteristics for 4525 Children by Duration of Sleep With Adjusted Average Sleep Durations

Hours of Self-reported Sleep on a School Nighta
<9 h9–9.9 h10–10.9 h11–11.9 h≥12 hAdjusted Mean Sleep Hours (95 % CI)Pb
N 279 (6.2%)841 (18.6%)2014 (44.5%)1166 (25.8%)225 (5%)
Average age, y (SD)10.0 (0.4)10.0 (0.4)10.0 (0.4)9.0 (0.4)9.8 (0.4)10.3 (10.2 to 10.3).05
Boys180 (8.2)431 (19.7)963 (44.1)501 (22.9)110 (5.0)10.2 (10.1 to 10.2)
Girls99 (4.2)410 (17.5)1051 (44.9)665 (28.4)115 (4.9)10.4 (10.3 to 10.4)<.0001
Ethnic group
 White European43 (3.9)179 (16.4)493 (45.3)316 (29.0)58 (5.3)10.4 (10.3 to 10.5)<.0001
 Black African-Caribbean87 (7.6)245 (21.4)508 (44.4)252 (22.0)51 (4.5)10.1 (10.1 to 10.2)
 South Asian89 (7.2)217 (17.5)551 (44.4)335 (27.0)50 (4.0)10.2 (10.2 to 10.3)
 Asian other17 (6.1)56 (20.1)121 (43.5)71 (25.5)13 (4.7)10.2 (10.1 to 10.3)
 Other43 (5.6)144 (18.6)341 (44.1)192 (24.8)53 (6.9)10.3 (10.2 to 10.4)
Parental socioeconomic position
 Managerial, professional55 (4.3)220 (17.4)629 (49.6)316 (24.9)47 (3.7)10.3 (10.2 to 10.4).04
 Intermediate75 (6.5)239 (20.6)511 (44.1)290 (25.0)45 (3.9)10.2 (10.1 to 10.3)
 Routine, manual96 (6.9)254 (18.3)586 (42.3)361 (26.1)88 (6.4)10.3 (10.2 to 10.3)
 Economically inactive33 (7.2)77 (16.9)171 (37.5)143 (31.4)32 (7.0)10.3 (10.2 to 10.4)
 Unclassified or missing20 (7.8)51 (19.8)117 (45.5)56 (21.8)13 (5.1)10.2 (10.1 to 10.3)
  • a Values are mean and SD for age; for all categorical variables, values are N (row %).

  • b P value from likelihood ratio test for heterogeneity is from the same multilevel model.