Poor Sleep A Significant Risk Factor for Childhood Obesity
Chronic sleep loss has been associated with an increased risk of weight gain in adults, but now experts are saying that lack of adequate nighttime sleep in infants and preschoolers is also a significant risk factor for later childhood obesity.
Ages 0 to 5 A "Critical Window" for Adequate Sleep
Using data from a national longitudinal study, Janice F. Bell PhD MPH of the University of Washington and Fredrick J. Zimmerman PhD of the University of California Los Angeles studied sleep and weight data on 1,930 children ages 0 to 13 in 1997. The children were divided into two groups: one “younger” (aged 1 to 59 months) and one “older” (age 5 to 13).
The same data was collected on the children five years later in 2002. Overweight was defined as being at or above the 85th percentile of national growth standards and obesity was defined as being at or above the 95th percentile.
At the end of the study, 33% of the younger cohort were above the 85th percentile and 36% of the older children were overweight or obese.
Among the younger children, those who did not get sufficient sleep (defined as less than 10 hours at night) between the ages of 1 month and 5 years were 80% more likely to be overweight or obese. Of the children at the beginning of the study who were older than 5, lack of sleep did not necessarily raise the risk of a normal weight child becoming obese, but there was a greater risk of a shift from overweight at the beginning of the study to becoming obese at the follow-up.
Trying to “make up” sleep during the day with naps was not an effective substitute for adequate nighttime sleep, according to the researchers.
Chronic sleep loss has many potential effects on the risk of weight gain. First, tired kids may exercise less and eat more during the day. Second, key hormones that regulate weight and metabolism are affected by lack of adequate sleep.
"Sleep duration is a modifiable risk factor with potentially important implications for obesity prevention and treatment," the authors concluded. "Insufficient nighttime sleep among infants and preschool-aged children appears to be a lasting risk factor for subsequent obesity, while contemporaneous sleep appears to be important to weight status in adolescents.”
Bell JF, Zimmerman FJ "Shortened nighttime sleep duration in early life and subsequent childhood obesity" Arch Pediatr Adolesc Med 2010; 164(9): 840-845.