Lack of Sleep May Increase Body Mass Index in Children

Each additional hour of sleep is associated with a BMI reduction in children aged 3 to 5 years

TUESDAY, May 31 (HealthDay News) -- Young children who do not get enough sleep may have an increased risk of becoming overweight, according to a study published online May 26 in BMJ.

Philippa J. Carter, from the University of Otago in Dunedin, New Zealand, and colleagues investigated whether reduced sleep in children is correlated with differences in body composition and the risk of becoming overweight. A cohort of 244 children were followed up from age 3 to 7 years, during which time body mass index (BMI); fat mass and free fat mass; dual energy X-ray absorptiometry; sleep duration; physical activity; television viewing; dietary intake; and family factors such as birth weight, smoking during pregnancy, maternal BMI, and education were measured.

The investigators found that, after adjusting for multiple variables, each extra hour of sleep correlated with a BMI reduction of 0.48 (95 percent confidence interval [CI], 0.01 to 0.96) for 3 to 5 year olds, and a reduction of 0.39 (95 percent CI, 0.24 to 0.63) in the risk of being overweight at age 7. This correlation was strengthened by additional adjustments for BMI at age 3. Changes in the fat mass index (−0.43) influenced differences in BMI more than in the fat free mass index (−0.21).

"Youngsters who sleep less are more likely to be overweight, with high body fat values, even after adjustment for lifestyle variables that can also influence body weight," the authors write.

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