Children who get less than the recommended amount of sleep for their age are at a higher risk of developing obesity, a study has found. Researchers at the University of Warwick in the UK found that children and adolescents who regularly sleep less than others of the same age gain more weight when they grow older and are more likely to become overweight or obese. “Being overweight can lead to cardiovascular disease and type-2-diabetes which is also on the increase in children. The findings of the study indicate that sleep may be an important potentially modifiable risk factor (or marker) of future obesity,” said Michelle Miller, from Warwick Medical School. The study published in the journal Sleep reviewed the results of 42 population studies of infants, children and adolescents aged 0 to 18 years which included a total of 75,499 participants.
Their average sleep duration was assessed through a variety of methods, from questionnaires to wearable technology. The participants were grouped into two classifications: short sleeper and regular sleepers. Short sleepers were defined as having less sleep than the reference category for their age. This was based on the most recent guidelines in the US which recommends that infants (4 to 11 months) get between 12-15 hours of nightly sleep, that toddlers (1-2 years) get 11-14 hours of sleep, children in pre-school (3-5 years) get 10-13 hours and school aged children (6-13 years) between 9 and 11 hours. Teenagers (14-17 years) are advised to get 8-10 hours.
Participants were followed up for a median period of three years and changes in BMI and incidences of overweight and/or obesity were recorded over time. At all ages short sleepers gained more weight and overall were 58 per cent 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. The study also reinforces the concept that sleep deprivation is an important risk factor for obesity, detectable very early on in life,” said Miller. “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,” said Francesco Cappuccio from University of Warwick.
“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,” said Cappuccio.