Table 1. Characteristics of the 815 participants in the Copenhagen Social Network Study.
| Smartphone interrupted sleepa | |||||
|---|---|---|---|---|---|
| Total population (n = 815) |
Uninterrupted (n = 502) |
Occasionally interrupted (n = 273) |
Frequently interrupted (n = 40) |
P-value | |
| Socio-demographic measures | |||||
| Women, n (%) | 185 (23) | 102 (21) | 68 (23) | 15 (33) | 0.17 |
| Age, mean (sd) | 21.6 (2.6) | 21.6 (2.8) | 21.7 (2.5) | 21.2 (1.5) | 0.52 |
| Self-reported sleep measures | |||||
| Sleep duration, mean (sd) | 7.6 (1.1) | 7.8 (1.1) | 7.5 (1.0) | 7.0 (1.1) | <0.001 |
| Karolinska Sleep Questionnaire itemsb | |||||
| Difficulties falling asleep, n (%) | 131 (16) | 72 (15) | 54 (19) | 5 (11) | 0.20 |
| Disturbed/uneasy sleep, n (%) | 86 (11) | 53 (11) | 29 (10) | 4 (9) | 0.86 |
| Repeated awakenings, n (%) | 32 (4) | 17 (4) | 14 (5) | 1 (2) | 0.44 |
| Premature awakenings, n (%) | 87 (11) | 54 (11) | 28 (10) | 5 (11) | 0.63 |
| Disturbed sleep scorec, mean (sd) | 2.1 (0.7) | 2.1 (0.7) | 2.1 (0.7) | 1.8 (0.7) | 0.12 |
a Smartphone interrupted sleep is defined as less than 6 hours on consecutive smartphone inactivity during self-reported sleep on weekday (Fridays and weekends excluded) over a four week period. Uninterrupted (no smartphone interrupted sleep); occasionally interrupted (defined as one to three nights with smartphone interrupted sleep), and frequently interrupted (defined as four or more nights with smartphone interrupted sleep).
b Reporting ‘almost every night’ or ‘several times a week’ for each item
c The four items of the Karolinska Sleep Questionnair were combined into an index reflecting the average frequency of symptoms (range 1 to 5)