Sleep Activity Patterns is Childhood: A Longitudinal Analysis

• In Event: Poster Session 14
  In Poster Session: PS 14 Topic - Perceptual, Sensory, Motor

Abstract

Physical activity, as a proxy for energy expenditure, has long been recognized as a factor in preventing excess weight gain (Hills, Andersen & Byrne, 2011). With child obesity rates at near epidemic levels, otter factors, such as portion control, sugar-sweetened beverages, and infrequent family meals have also been identified as contributing to the problem. In recent years, research has also suggested an increased risk of obesity among children who exhibit shorter sleep duration (Bell & Zimmerman, 2010; Capuccio et al., 2008). The purpose of the present study was to track the pattern of sleep activity in children over the preschool years, and to additionally examine its possible associations with children’s weight status.
As part of a longitudinal study on infant nutrition and growth, 75 children, recruited through their mothers’ enrollment at a local WIC Center, were visited in their homes at 1-, 2-, 3-, and 4-years of age. Mothers self-reported s Black, Hispanic, or Mexican. Although multiple measures were obtained, the present report is confined to their anthropometric and motor activity estimates. On Day 1 of a two-day home visit, subjects were measured and weighed with an infant (Tanita BD 585) or standing digital scale (Omron). Prior to departing, the Research Assistant fastened an accelerometer (Actical Activity Monitor) to the child’s left ankle. The RA returned on Day 2 at a time one hour later than the previous day, to ensure that 24 hours of data would have been recorded, and retrieved the accelerometer to download at our laboratory.
Results are as follows
Age, BMI Percentile, Minutes (hours), Activity counts, Counts/minute
• 1 year, 70.27, 694 (11.56), 10,850, 14.96
• 2 years, 70.62, 650 (10.83), 7,509, 11.71
• 3 years, 71.35, 671 (11.18), 9,486, 11.50
• 4 years, 77.55, 611 (10.18), 5,419, 8.60
As can be seen, sleep duration generally declined over the four years, showing the largest amount at age 1-year and shortest at 4-years, though all averages were in the ranges recommended by pediatricians (11-14 for 1-2s, 10-13 for 3-4s, American Academy of Pediatrics).
To examine the possible associations between sleep activity and weight status, correlations were run between weight-for-length (at 1-year) and BMI-for age percentiles, minutes of sleep, and average activity counts per minute of sleep. Two significant correlations emerged: Total minutes of sleep at age 3-years was negatively correlated with BMI-for-age at 4-years (r= –.314, p<.01) and BMI-for-age at 4-years was also correlated with average activity per minute at 4-years.
These results reflect the expected pattern of less sleep being required as infants move into early childhood, but also support the association between sleep and excess weight gain. As the average child at age 4 was at the 77th percentile of BMI-for-age, the urgency of identifying all reasonable causes of child overweight must remain a priority.

Author

• John Worobey, Rutgers University - New Brunswick
  Presenting Author