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Table 1 Demographic data and sleep habits in university students in Japan and China

From: Is the use of high correlated color temperature light at night related to delay of sleep timing in university students? A cross-country study in Japan and China

  Japanese
(n = 447)
Chinese
(n = 327)
 
Mean age (years) 21.5 (1.6) 23.3 (2.7) **
Sex, %male 62.8 53.4 **
Sleep habits (school days)
  Bedtime 01:09 (1:01) 23:58 (0:43) ***
 Sleep latency (min) 15.1 (11.3) 16.1 (11.7) n.s.
 Sleep onset time 01:24 (1:02) 00:15 (0:46) ***
 Wake time 08:01 (1:11) 07:42 (0:49) ***
 Midpoint of sleep 04:43 (0:57) 3:58 (0:39) ***
 Sleep period time (h) 6.62 (1.13) 7.46 (0.90) ***
Sleep habits (free days)
  Bedtime 01:37 (1:12) 00:22 (0:51) ***
 Sleep latency (min) 16.0 (13.0) 14.9 (11.7) n.s.
 Sleep onset time 01:52 (1:14) 00:38 (0:52) ***
 Wake time 09:35 (1:25) 08:46 (1:01) ***
 Midpoint of sleep 05:45 (1:11) 4:42 (0:49) ***
 Sleep period time (h) 7.70 (1.25) 8.15 (0.95) ***
Social jet lag (h) 1.04 (0.82) 0.73 (0.56) ***
  1. Values are means and SD
  2. Adjusted by age and sex **p < 0.01, ***p < 0.001, n.s not significant