MONDAY, Sept. 6, 2010 (HealthDay News) -- Infants and preschoolers who don't get enough sleep at night are at increased risk for later childhood obesity, a new study suggests.
The researchers also found that daytime naps are not an adequate substitute for lost nighttime sleep in terms of preventing obesity.
The study included 1,930 U.S. children, ages 1 month to 13 years, who were divided into two groups -- younger (ages 1 month to 59 months) and older (ages 5 to 13 years). Data on the children was collected at the start of the study (baseline) in 1997 and again in 2002 (follow-up).
At the follow-up, 33 percent of the younger children and 36 percent of the older children were overweight or obese. Among the younger children, lack of sufficient nighttime sleep at baseline was associated with increased risk for later overweight or obesity.
Among the older children, the amount of sleep at baseline was not associated with weight at follow-up. However, a lack of nighttime sleep at follow-up was associated with increased risk of a shift from normal weight to overweight and from overweight to obesity, the study found.
The findings "suggest that there is a critical window prior to age 5 years when nighttime sleep may be important for subsequent obesity status," wrote Janice F. Bell of the University of Washington in Seattle, and Frederick J. Zimmerman of the University of California, Los Angeles.
"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. Napping had no effects on the development of obesity and is not a substitute for sufficient nighttime sleep," they added.
The study is published in the September issue of the journal Archives of Pediatrics & Adolescent Medicine.
The Nemours Foundation has more about children and sleep.