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. 2022 Jul 1;20(4):541-549.
doi: 10.1007/s41105-022-00400-w. eCollection 2022 Oct.

Sleep-wake patterns and disturbances in Portuguese primary school children: a comparison between 1995 and 2016

Maria Inês Clara  1   2 , Vanda Clemente  1   2   3 , Joana Abrantes  4 , Daniel R Marques  2   4 , Maria H P Azevedo  5 , Ana Allen Gomes  1   2
Affiliations

Sleep-wake patterns and disturbances in Portuguese primary school children: a comparison between 1995 and 2016

Maria Inês Clara et al. Sleep Biol Rhythms. .

Abstract

Purpose: It is often assumed sleep duration has decreased and sleep schedules have delayed over the last decades, as society modernized. We aimed to investigate changes in the sleep patterns of school-age children over time.

Methods: We compared the sleep timings, durations, and disturbances of primary school-age children in 1995 and roughly two decades later, in 2016. Data from 666 children attending the 3rd and 4th grades of basic education were combined from two different cross-sectional school-based studies conducted within the same educational region of mainland Portugal using the same parent-report questionnaire (Children's Sleep-wake Patterns Questionnaire).

Results: Mean sleep duration did not differ significantly between the two time points (schooldays: t = .118, p = .906; free days: t = 1.310, p = .191), albeit the percentage of children sleeping the recommended number of hours decreased significantly in 2016 when compared to 1995 (schooldays: χ2 = 4.406, p = .036; free days: χ2 = 16.859, p < .001). Wake-times advanced on free days in 2016. Difficulties on settling to sleep alone and returning to sleep were more prevalent in 2016, as well as fearing the dark and needing lights on or parent's presence to fall asleep.

Conclusions: Sleep onset-related disturbances appear to have increased from 1995 to 2016. One possible explanation for this increase might be the change in parental practices preventing children from learning to fall asleep autonomously.

Keywords: Children; Sleep disturbances; Sleep duration; Sleep timing; Sleep–wake behaviors.

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Conflict of interest statement

Conflict of interestThe authors have no conflicts of interest to declare.Ethical standardsThe authors declare that the procedures were followed according to the regulations established by the Clinical Research and Ethics Committee and to the Helsinki Declaration of the World Medical Association updated in 2013. The authors declare having followed the protocols in use at their working center regarding patients’ data publication. The authors have no conflicts of interest to declare.

Figures

Fig. 1
Fig. 1
Overall, children’s bedtime difficulties were more prevalent in 2016, including needing lights on to fall asleep [χ2 = 9.103, p = .003] and falling asleep in parents’ bed [χ2 = 1.491, p = .22], although the latter did not reach statistical significance. Albeit not reaching statistical significance, the prevalence of bedtime resistance [χ2 = .004, p = .947] was slightly higher in 1995
Fig. 2
Fig. 2
Except for experiencing fear of sleeping in the dark [χ2 = 9.319, p = .002] and difficulties going back to sleep after a night awakening [χ2 = 12.558, p < .001], there were no statistically significant differences between 1995 and 2016 concerning the prevalence of nighttime disturbances, including loud snoring [χ2 = .002, p = .968] and night terrors [χ2 = .054, p = .817]. Somniloquy [χ2 = .054, p = .816] was the most prevalent nighttime disturbance on both time marks, followed by bruxism [χ2 = .346, p = .557] and nightmares [χ2 = .477, p = .490]. In 1995, sleepwalking [χ2 = .048, p = .827] was the less prevalent parasomnia. The less prevalent parasomnia in 2016 was enuresis [χ2 = 3.131, p = .077]
Fig. 3
Fig. 3
Daytime sleepiness [χ2 = .478, p = .489], fatigue [χ2 = .466, p = .495] and irritability [χ2 = 24.592, p < .001] were slightly more prevalent in 1995 than 2016. The latter was the only daytime disturbance differing significantly between the two time points
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