| More Details: |
Myrtha E Reyna-Vargas,1 Arpita Parmar,2 Diana L Lefebvre,3 Meghan B Azad,4– 6 Allan B Becker,4,5 Stuart E Turvey,7 Theo J Moraes,1 Wendy Lou,8 Padmaja Subbarao,1,8 Malcolm R Sears,3 Piushkumar J Mandhane,9 Indra Narang1,10 1Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; 2Sculich School of Medicine and Dentistry, Western University, London, ON, Canada; 3Department of Medicine, McMaster University, Hamilton, ON, Canada; 4Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada; 5Developmental Origins of Chronic Diseases in Children Network (DEVOTION), Children’s Hospital, Winnipeg, MB, Canada; 6Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada; 7Department of Pediatrics, BC Children’s Hospital, University of British Columbia, Vancouver, BC, Canada; 8Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada; 9Department of Pediatrics, University of Alberta, Edmonton, AB, Canada; 10Faculty of Medicine, University of Toronto, Toronto, ON, CanadaCorrespondence: Indra Narang, The Hospital for Sick Children, 555 University Ave-Hill Wing Room #4534, Toronto, ON, M5G 1X8, Canada, Email indra.narang@sickkids.caIntroduction: Decreased sleep duration and increased screen time as early as preschool age may contribute to overweight and obesity. The effects of bedtime together with nocturnal sleep duration remain unclear with a paucity of data evaluating these associations longitudinally. We aim to evaluate the independent and joint effects of sleep duration, sleep bedtime, and screen time at 3 years of age on BMI status, particularly overweight and obesity by age 5 years.Methods: Data from 2185 participants of the CHILD Cohort Study were analyzed longitudinally using generalized estimating equations (GEE). Models included changes in overweight/obesity status from 3 to 5 years of age as outcome, and nocturnal sleep duration, bedtime, and daily screen time at 3 years of age as explanatory variables. The joint effects of nocturnal sleep time and excess screen time, late bedtime on overweight/obesity were subsequently analyzed.Results: The median nocturnal sleep time at 3 and 5 years of age was 11.0 hours/night [IQR 10.5, 11.5]. A total of 14.5% children went to bed after 9PM at 3 years and 7.2% at 5 years. Median screen time was 1.0 hr/day [IQR 1.0, 2.0] at both ages. Longitudinal analyses showed that sleeping less than 10.5 hours at age 3 years was associated with 46% greater odds of overweight/obesity by age 5 years (OR 1.46, 95% CI 1.07, 2.00). The risk was higher when coupled with late bedtime after 9pm (OR 1.60, 95% CI 1.12, 2.31). Children with both short nocturnal sleep duration and excess screen time (> 1hr/day) had twice the associated risk of overweight/obesity by age 5 years (OR 1.96, 95% CI 1.34, 2.88).Conclusion: Nocturnal sleep duration and screen time are modifiable risk factors in young children, which may have important implications for obesity prevention as early as infancy.Keywords: Nocturnal sleep, bedtime, BMI |
