A new large-scale review adds to the growing body of evidence that children and teenagers who fail to get the recommended amount of sleep for their age have a higher risk of developing obesity.

Carried out by researchers at the University of Warwick, U.K., the study reviewed the results of 42 population studies which included a total of 75,499 infants, children, and adolescents aged 0 to 18 years old.

The participants' average sleep duration had been assessed using a variety of methods, from questionnaires to wearable technology.

The researchers split the participants into two groups -- short sleepers and regular sleepers -- and followed them for a median period of three years. Short sleepers were defined as those who got less sleep than the National Sleep Foundation recommended for their age.

These guidelines recommend that:

  • infants (4 to 11 months) get between 12-15 hours of nightly sleep
  • toddlers (1-2 years) get 11-14 hours of sleep
  • children in pre-school (3-5 years) get 10-13 hours
  • school aged children (6-13 years) get between 9 and 11 hours
  • teenagers (14-17 years) should get 8-10 hours.

The researchers found that short sleepers at all ages gained more weight than regular sleepers and overall were 58% more likely to become overweight or obese.

"The results showed a consistent relationship across all ages indicating that the increased risk is present in both younger and older children," commented co-authors Dr. Michelle Miller, adding that, "The study also reinforces the concept that sleep deprivation is an important risk factor for obesity, detectable very early on in life."

"Being overweight can lead to cardiovascular disease and type 2 diabetes which is also on the increase in children."

Co-author Professor Francesco Cappuccio noted, "By appraising world literature we were able to demonstrate that, despite some variation between studies, there is a strikingly consistent overall prospective association between short sleep and obesity. This study builds on our previous analysis of cross-sectional data published in 2008. The importance of the latest approach is that only prospective longitudinal studies were included, demonstrating that short sleep precedes the development of obesity in later years, strongly suggesting causality."

The results can be found published online in the journal Sleep.