Sleep duration and body mass index in 0–7-year olds
- 1Centre for Community Child Health, Royal Children's Hospital, Parkville, Victoria, Australia
- 2Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- 3Department of Paediatrics, University of Melbourne, Parkville, Melbourne, Victoria, Australia
- Correspondence to Dr Harriet Hiscock, Centre for Community Child Health, Royal Children's Hospital, Flemington Road, Parkville, Vic 3052, Australia;
Contributors All authors contributed to the manuscript, as follows: HH and MW conceived this study; HH, KS, LC and MW wrote the manuscript; LC and KS carried out the statistical analyses and had full access to all of the data in the study; HH takes responsibility for the integrity of the data and the accuracy of the data analysis.
- Accepted 25 March 2011
- Published Online First 28 May 2011
Objectives To determine in children aged 0–7 years (1) cross-sectional relationships between body mass index (BMI) and sleep duration, and whether (2) sleep duration predicts later BMI and/or (3) BMI predicts later sleep duration.
Design Longitudinal Study of Australian Children, Waves 1 and 2.
Participants Infants aged 0–1 years (Wave 1), followed at age 2–3 years (Wave 2); children aged 4–5 years (Wave 1), followed at age 6–7 years (Wave 2).
Main outcome measures BMI, sleep duration by time-use diary, parent-reported sleep problems (none/mild vs moderate/severe). Analyses: Cross-sectional, ANOVA (sleep duration) and χ2 (sleep problems); longitudinal, linear regression.
Results 3857 (76%) infants and 3844 (77%) children had BMI and sleep data. At every wave, approximately 15% and 5% of children were overweight and obese, respectively. Obesity was not associated with sleep duration at 0–1, 2–3 or 4–5 years, though obese 6–7-year olds slept approximately 30 min less (p<0.001). Sleep problems were similar across BMI categories at all ages. Wave 1 sleep duration did not predict Wave 2 BMI, nor did Wave 1 BMI predict Wave 2 sleep duration.
Conclusions In these large child population cohorts, sleep duration did not predict obesity up to age 6–7 years. Current trials of sleep interventions to prevent or manage obesity in young children may be premature.
Funding The Longitudinal Study of Australian Children (LSAC) was initiated and is funded by the Commonwealth Department of Families, Housing, Community Services and Indigenous Affairs (FaHCSIA) and is managed by the Australian Institute of Family Studies (AIFS). The authors’ work was independent of the funders. MW was supported by NHMRC Population Health Career Development Awards #284556 and #546405, and HH by NHMRC Public Health Capacity Building Grant #436914.
Competing interests None.
Ethics approval This study was conducted with the approval of the Australian Institute of Family Studies Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.