DOI: 10.5281/zenodo.11560950
title: Self-reported and accelerometry measures of sleep components in adolescents living in Pacific Island countries and territories: Exploring the role of sociocultural background

description: Data from self-report questionnaires and accelerometer extraction on sleep components (onset sleep time, wake-up time and sleep duration on weekdays and weekend).

Participant characteristics: 10 to 16 years old students.

Number of participants: 182.

Year of the study: 2018 - 2019.

Place of the study: New Caledonia.
description: Consent

Written consent was obtained from the children's parents before the start of the study. The project was first authorized by the Vice-Rectorate and then presented to the school directors. The targeted schools were contacted, and the project was then proposed to the teaching teams for their acceptance.

Data collection and filter

Data were collected between July 2018 and April 2019, from 1060 school-going adolescents (10–16 years old) during class time. In each school, two classes per level (6th, 5th, 4th, 3rd) were chosen to respond to the anonymous questionnaire, which consisted of two parts lasting 30 minutes each and was carried out in two stages.

About 30 participants (according to the number of devices available) per school were randomly selected to wear a GENEActiv accelerometer device for 7 consecutive days. Consenting participants wore the device for 7 days. When a participant refused to wear the device, another random draw was made. A total of 211 adolescents accepted to wear an accelerometer device.

We removed participants who provided incomplete responses regarding sleep components, having worn a defective device or with missing accelerometer data. There were 182 participants with complete data.

Sleep measurements

Self-reported sleep measurements

Participants self-reported their sleep duration for weekdays and weekends with the four following questions:



Quand tu as cours le lendemain matin, d'habitude, à quelle heure t'endors-tu ? [en: When you have class the day after, what time do you usually fall asleep?]

Quand tu n'as PAS cours le lendemain matin, d'habitude, à quelle heure t'endors-tu ? [en: When you don't have class the day after, what time do you usually fall asleep?]

Quand tu as cours le matin, d'habitude, à quelle heure te réveilles-tu ? [en: When you have morning classes, what time do you usually wake up?]

Quand tu n'as PAS cours le matin, d'habitude, à quelle heure te réveilles-tu ? [en: When you don't have morning classes, what time do you usually wake up?]


There were 13 available categories for the time an adolescent might fall asleep from "Avant 21h (9h du soir)" [en: "Before 9 p.m."] to "Environ 3h (3h du matin) ou plus tard" [en: "Around 3 a.m. or later"] and 15 available categories for the wake-up time from "Avant 5h du matin" [en: "Before 5 a.m."] to "Midi ou plus tard" [en: "Around midday or later"], both with a 30-min interval between each category.

Answers have been converted into numerical values to get the "self-reported" values as follows:



"Avant 21h (9h du soir)" [en: "Before 9 p.m."] -> 20.5

"Pas plus tard que 21h (9h du soir)" [en: "Not later than 9 p.m."] -> 21

"Environ 21h30 (9h30 du soir)" [en: "Around 9:30 p.m."] -> 21.5

...

"Environ 3h (3h du matin) ou plus tard" [en: "Around 3 a.m. or later"] -> 27 (24 + 3)

"Avant 5h du matin" [en: "Before 5 a.m."] -> 28.5 (24 + 4.5)

"Pas plus tard que 5h du matin" [en: "Not later than 5 a.m."] -> 29 (24 + 5)

"Environ 5h30 du matin" [en: "Around 5:30 a.m."] -> 29.5 (24 + 5.5)

...

"Midi ou plus tard" [en: "Around midday or later"] -> 36 (24 + 12)


Sleep measurements with accelerometer

The GENEActiv .bin files were processed by using the R package GGIR 1.6-7 in R 3.5.1 [R Core Team. (2018). A language and environment for statistical computing. http://www.R-project.org/; van Hees, V. T., Sabia, S., Anderson, K. N., Denton, S. J., Oliver, J., Catt, M., Abell, J. G., Kivimäki, M., Trenell, M. I., & Singh-Manoux, A. (2015). A novel, open access method to assess sleep duration using a wrist-worn accelerometer. PLoS ONE, 10(11), e0142533. https://doi.org/10.1371/journal.pone.0142533; van Hees, V. T., Sabia, S., Jones, S. E., Wood, A. R., Anderson, K. N., Kivimäki, M., Frayling, T. M., Pack, A. I., Bucan, M., Trenell, M. I., Mazzotti, D. R., Gehrman, P. R., Singh-Manoux, B. A., & Weedon, M. N. (2018). Estimating sleep parameters using an accelerometer without sleep diary. Scientific Reports, 8(1), 12975. https://doi.org/10.1038/s41598-018-31266-z]. We did not use any sleep log for participants and the sleep period time was assessed by the HDCZA alorithm [van Hees, V. T., Sabia, S., Jones, S. E., Wood, A. R., Anderson, K. N., Kivimäki, M., Frayling, T. M., Pack, A. I., Bucan, M., Trenell, M. I., Mazzotti, D. R., Gehrman, P. R., Singh-Manoux, B. A., & Weedon, M. N. (2018). Estimating sleep parameters using an accelerometer without sleep diary. Scientific Reports, 8(1), 12975. https://doi.org/10.1038/s41598-018-31266-z]. The default method from this package was used to classify sleep periods [van Hees, V. T., Sabia, S., Anderson, K. N., Denton, S. J., Oliver, J., Catt, M., Abell, J. G., Kivimäki, M., Trenell, M. I., & Singh-Manoux, A. (2015). A novel, open access method to assess sleep duration using a wrist-worn accelerometer. PLoS ONE, 10(11), e0142533. https://doi.org/10.1371/journal.pone.0142533].

Outputs from this process enabled to get, for every recorded night, assessments for: onset sleep time, wake-up time and sleep duration. Outputs were automatically merged into weekdays and weekends.

Comparisons with the NSF recommendations

The (American) National Sleep Foundation (NSF) provided sleep time recommandations according to age categories of individuals [Hirshkowitz, M., Whiton, K., Albert, S. M., Alessi, C., Bruni, O., DonCarlos, L., Hazen, N., Herman, J., Katz, E. S., Kheirandish-Gozal, L., Neubauer, D. N., O'Donnell, A. E., Ohayon, M., Peever, J., Rawding, R., Sachdeva, R. C., Setters, B., Vitiello, M. V., Ware, J. C., & Adams Hillard, P. J. (2015). National Sleep Foundation's sleep time duration recommendations: Methodology and results summary. Sleep Health, 1(1), 40–43. https://doi.org/10.1016/j.sleh.2014.12.010]. We categorized the sleep assessments (self-reported and by accelerometry) according to these recommendations, as follows:



insufficient: below the recommended range

appropriate: into the recommended range ("School-aged children", i.e. 6-13 years old = [9;11]; "Teenagers", i.e. 14-17 years old = [8;10])

excessive: beyond the recommended range


Alignment of accelerometry and self-reported assessments

Participants' answers were classified into 3 categories according to the accelerometry assessments:



Underestimated: the participant underreported the time of his/her sleep component by 30 minutes or more, compared with accelerometry assessment

Aligned: the participant's response matched within 30 min of accelerometry sleep measure

Overestimated: the participant overreported the time of his/her sleep component by 30 minutes or more, compared with accelerometry assessment


Socio-demography

The place of living (rural and urban) was determined according to the school location and the criterion used in previous studies that used the European standard to assess the degree of urbanization [The European Union labour force survey. (2001). Methods and definitions - (Eurostat, Guidelines, Labour statistics, Survey). Accessed November 17, 2017. https://unstats.un.org/unsd/EconStatKB/KnowledgebaseArticle10230.aspx].

Ethnic community was self-reported by the adolescents and classified according to the recommendations of the INSERM [INSERM. Documents: Situation sociale et comportements de santé des jeunes en Nouvelle Calédonie — Premiers résultats, Mars 2008. https://documentation.outre-mer.gouv.fr/i-Record.htm?idlist= 1&record=19103288124919214609] report on New Caledonia, but we did not allow the students to report belonging to more than one ethnic group. Ethnic categorization was based on the question: "A quelle communauté te sens-tu appartenir ?" [en: "Which community do you feel you belong to?"]. Participants who answered belonging to "Wallisienne, Futunienne, Tahitienne (Polynésienne)" [en: "Wallisian, Futunian, Tahitian (Polynesian)"], "Indonésienne, Vietnamienne ou Asiatique d'autre origine" [en: "Indonesian, Vietnamese or Asian from another background"], "Africaine" [en: "African"] or "Autre" [en: "Other"] were merged in an only one category called "Autre" [en: "Other"]. Participants who answered "Européenne Calédonienne (né(e) en Calédonie)" [en: "European born in New Caledonia"] or "Européenne métro, né(e) en France ou ailleurs" [en: "European born in a place different from New Caledonia"] have been aggregated into a single categoy: "Caucasian". This results in a 3-category-variable: Caucasian, Melanesian and Other.

Socio-economic status (SES) was indexed based on the occupation of the household reference person (defined as the householder with the highest income) using the National Statistics Socio-Economic classification [Krieger N. A Researcher’s Guide to the National Statistics Socio-Economic Classification. J Public Health Policy. 2003; 24(3–4):467–73]. For the present analyses, we generated three categories: managerial and professional occupations (high SES), intermediate occupations (medium SES) and routine and manual occupations (low SES).
description: Description of the columns

ID: Participant ID for this studySex: sex of participants ("Male" or "Female")Place of living: area type of the school ("Rural" or "Urban")Ethnic community: ethnic community declared by participants ("Caucasian", "Melanesian" or "Other")SES: socio-economic status ("Low", "Medium" or "High")Age (months): age of the participants in months when data collectionSelf-reported onset sleep time on weekdays: Numeric conversion of participants' answers about their onset sleep time on weekdaysSelf-reported onset sleep time on weekend: Numeric conversion of participants' answers about their onset sleep time on weekend daysSelf-reported wake-up time on weekdays: Numeric conversion of participants' answers about their wake-up time on weekdaysSelf-reported wake-up time on weekend: Numeric conversion of participants' answers about their wake-up time on weekend daysSelf-reported sleep duration on weekdays: difference between wake-up time and onset sleep time on weekdays (Self-reported wake-up time on weekdays - Self-reported onset sleep time on weekdays)Self-reported sleep duration on weekend: difference between wake-up time and onset sleep time on weekend days (Self-reported wake-up time on weekend - Self-reported onset sleep time on weekend)Accelerometry onset sleep time on weekdays: Accelerometry assessment of onset sleep time on weekdaysAccelerometry onset sleep time on weekend: Accelerometry assessment of onset sleep time on weekend daysAccelerometry wake-up time on weekdays: Accelerometry assessment of wake-up time on weekdaysAccelerometry wake-up time on weekend: Accelerometry assessment of wake-up time on weekend daysAccelerometry sleep duration on weekdays: difference between wake-up time and onset sleep time on weekdays (Accelerometry wake-up time on weekdays - Accelerometry onset sleep time on weekdays)Accelerometry sleep duration on weekend: difference between wake-up time and onset sleep time on weekend days (Accelerometry wake-up time on weekend - Accelerometry onset sleep time on weekend)Self-reported NSF recommendations on weekdays: comparison of (American) National Sleep Foundation recommendations and participants' answers regarding sleep duration on weekdays ("insufficient", "appropriate" or "excessive")Self-reported NSF recommendations on weekend: comparison of (American) National Sleep Foundation recommendations and participants' answers regarding sleep duration on weekend days ("insufficient", "appropriate" or "excessive")Accelerometry NSF recommendations on weekdays: comparison of (American) National Sleep Foundation recommendations and accelerometry assessments regarding sleep duration on weekdays ("insufficient", "appropriate" or "excessive")Accelerometry NSF recommendations on weekend: comparison of (American) National Sleep Foundation recommendations and accelerometry assessments regarding sleep duration on weekend days ("insufficient", "appropriate" or "excessive")Self-reported and accelerometry alignment for onset sleep time on weekdays: alignment of onset sleep time assessments by accelerometry and questionnaire on weekdays ("Underestimated", "Aligned" or "Overestimated")Self-reported and accelerometry alignment for onset sleep time on weekend: alignment of onset sleep time assessments by accelerometry and questionnaire on weekend days ("Underestimated", "Aligned" or "Overestimated")Self-reported and accelerometry alignment for wake-up time on weekdays: alignment of wake-up time assessments by accelerometry and questionnaire on weekdays ("Underestimated", "Aligned" or "Overestimated")Self-reported and accelerometry alignment for wake-up time on weekend: alignment of wake-up time assessments by accelerometry and questionnaire on weekend days ("Underestimated", "Aligned" or "Overestimated")Self-reported and accelerometry alignment for sleep duration on weekdays: alignment of sleep duration assessments by accelerometry and questionnaire on weekdays ("Underestimated", "Aligned" or "Overestimated")Self-reported and accelerometry alignment for sleep duration on weekend: alignment of sleep duration assessments by accelerometry and questionnaire on weekend days ("Underestimated", "Aligned" or "Overestimated")