Table 2.
Nocturnal sleep duration of participating children by sex, country and season of sleep duration measurement
| Nocturnal sleep duration in decimal hours | ||
|---|---|---|
| mean (SD) | p value | |
| Sex | ||
| Boys | 9.11 (0.65) | < 0.001 |
| Girls | 9.36 (0.66) | |
| Country | ||
| Belgium | 9.74 (0.69) | < 0.001 |
| Germany | 9.51 (0.63) | |
| Poland | 9.19 (0.55) | |
| Italy | 9.11 (0.67) | |
| Spain | 9.10 (0.65) | |
| Seasona | ||
| Winter | 9.30 (0.61) | 0.63 |
| Spring | 9.19 (0.67) | |
| Summer | 9.21 (0.83) | |
| Autumn | 9.26 (0.63) | |
Significant p values are marked in bold
SD standard deviation
aMeteorological classification of season: winter = December, January, February; spring = March, April, May; summer = June, July, August; autumn = September, October, November