Children’s sleep patterns from 0 to 9 years: Australian population longitudinal study Anna M H Price, 1,2 Judith E Brown, 3 Michael Bittman, 3 Melissa Wake, 1,2,4 Jon Quach, 1,2 Harriet Hiscock 1,2,4 1 Murdoch Childrens Research Institute, Parkville, Victoria, Australia 2 Centre for Community Child Health, The Royal Children’s Hospital, Parkville, Victoria, Australia 3 School of Behavioural, Cognitive and Social Sciences, University of New England, Armidale, North South Wales, Australia 4 Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia Correspondence to Dr Anna Price, Centre for Community Child Health, The Royal Children’s Hospital, Flemington Road, Parkville, VIC 3052, Australia; anna.price@mcri.edu.au Received 27 March 2013 Revised 16 October 2013 Accepted 29 October 2013 ▸ http://dx.doi.org/10.1136/ archdischild-2013-304083 To cite: Price AMH, Brown JE, Bittman M, et al. Arch Dis Child Published Online First: [ please include Day Month Year] doi:10.1136/archdischild- 2013-304150 ABSTRACT Objective To provide accurate population normative data documenting cross-sectional, age-specific sleep patterns in Australian children aged 0–9 years. Design and setting The first three waves of the nationally representative Longitudinal Study of Australian Children, comprising two cohorts recruited in 2004 at ages 0–1 years (n=5107) and 4–5 years (n=4983), and assessed biennially. Participants Children with analysable sleep data for at least one wave. Measures At every wave, parents prospectively completed 24-h time-use diaries for a randomly selected week or weekend day. ‘Sleeping, napping’ was one of the 26 precoded activities recorded in 15-min time intervals. Results From 0 to 9 years of age, 24-h sleep duration fell from a mean peak of 14 (SD 2.2) h at 4–6 months to 10 (SD 1.9) h at 9 years, mainly due to progressively later mean sleep onset time from 20:00 (SD 75 min) to 21:00 (SD 60 min) and declining length of day sleep from 3.0 (SD 1.7) h to 0.03 (SD 0.2) h. Number and duration of night wakings also fell. By primary school, wake and sleep onset times were markedly later on weekend days. The most striking feature of the centile charts is the huge variation at all ages in sleep duration, sleep onset time and, especially, wake time in this normal population. Conclusions Parents and professionals can use these new centile charts to judge normalcy of children’s sleep. In future research, these population parameters will now be used to empirically determine optimal child sleep patterns for child and parent outcomes like mental and physical health. INTRODUCTION Insufficient or poor-quality sleep in childhood is associated with serious negative consequences including poorer emotional, behavioural and cogni- tive functioning, increased injury and obesity, and poorer parental mental and general health. 1–4 The cost of childhood sleep problems is considerable. For Australian families, the average cost associated with seeking professional healthcare to manage infant sleep problems in the second 6 months of life totals $A380 per family (adjusted for inflation to 2012). 5 Unpublished population data indicate that sleep problems in children aged 0–7 years (estimated population 1.14 million) are associated with a $A15.3 million cost to government in add- itional health services every year. 6 Matricciani’s recent systematic review verified the common perception that sleep duration in childhood (5–18 years) is decreasing. 7 Data from 218 studies (n=690 747 from 20 countries) showed that the median decrease in children’s sleep duration was 0.75 min per year since 1905. This could be contributing to the rise in morbidities such as childhood obesity and attention deficit dis- order recorded over recent decades. 8 It is equally possible that too much sleep is detri- mental to health. In a recent critical review, some adult studies suggested that short (<7 h) and long (≥8 h) nightly sleep duration could be associated with obesity (ie, a non-linear association). 9 Although comparable studies with children suggest only a negative linear relationship, more evidence could reveal complex, non-linear relationships. 9 Finally, and independently of duration, sleep timing and fragmentation may be important to children’s health. Olds et al 10 , studying time diary data in 2200 Australians aged 9–16 years, compared two groups with the same total sleep duration. Those What is already known ▸ Research interest in infant and child sleep has rapidly increased because of their relevance to ‘modern’ problems such as obesity and attention deficit disorder. ▸ Starting from infancy, there are steady age-related declines in duration, number/length of night wakes and length of daytime sleeps. ▸ However, current reference values are largely based on inaccurate parental summary or ‘stylised’ recall of sleep parameters, rather than accurately recorded population-level sleep data. What this study adds ▸ Time-use diaries provide population normative centile curves for sleep duration and, for the first time, sleep onset times and wake times throughout infancy and childhood. ▸ There is a striking range and steady decline in sleep duration, number of sleep episodes, number/length of night wakes and length of day sleeps. ▸ These population parameters can be used to determine optimal sleep patterns for children’s behavioural, emotional and cognitive outcomes, and parent outcomes like mental health. Price AMH, et al. Arch Dis Child 2013;0:1–7. doi:10.1136/archdischild-2013-304150 1 Original article ADC Online First, published on December 16, 2013 as 10.1136/archdischild-2013-304150 Copyright Article author (or their employer) 2013. Produced by BMJ Publishing Group Ltd (& RCPCH) under licence. group.bmj.com on December 17, 2013 - Published by adc.bmj.com Downloaded from