Chronic lack of sleep - as well as sleep-disordered breathing - doubles obesity risks for children, researchers have found.
Prof. Karen Bonuck - lead researcher from Albert Einstein College of Medicine of Yeshiva University in New York, NY - says lack of sleep "has become a well-recognized risk for childhood obesity."
She adds that sleep-disordered breathing (SDB) is also a risk factor for obesity and includes snoring and sleep apnea.
"These two risk factors had not been tracked together in children over time to determine their potential for independently influencing weight gain," she says, which is why she and her colleagues conducted their latest study.
According to the Centers for Disease Control and Prevention (CDC), during the past 30 years, childhood obesity has more than doubled in children and quadrupled in adolescents in the US.
Learning good sleep habits key to healthy and longer sleep
For their study, the researchers used data on nearly 2,000 children who were part of the Avon Longitudinal Study of Parents and Children (ALSPAC), which tracked children for 15 years in Avon in the UK.
The study contained questionnaire data from parents regarding child sleep duration and SDB symptoms from birth through 6.75 years, and it also utilized child BMI data from research ALSPAC clinics.
Results showed that children with the most severe cases of SDB had the greatest obesity risks; compared with the asymptomatic group of kids, they were twice as likely to become obese by ages 7, 10 and 15.
Though children whose SDB peaked at ages 5-6 turned out slightly better, they still had a 60-80% increased risk of becoming obese.
The researchers note that obesity was defined as having a body mass index (BMI) greater than the 95th percentile for age and gender, as set out by the International Obesity Task Force.
Another finding from the study was that children with the shortest sleep time at ages 5-6 also had a 60-100% increased risk of being obese at age 15. Interestingly, however, children with a short sleep duration at other ages did not experience an increase in risk.
Children with short sleep duration were defined as those who slept less than 90% of their peers. In children aged 5-6, for example, this was 10.5 hours or less per night.
"Learning good sleep habits and proper sleep hygiene can promote healthy sleep and longer sleep duration," says Prof. Bonuck, who notes that lack of sufficient sleep affects around 25-50% of preschoolers.
'Vital for parents, physicians to identify sleep problems early'
Though SDB and lack of sleep were both strong obesity risk factors, the team notes that their effects are independent of each other. After looking for links between short sleep duration and SDB across all age groups, the researchers found little evidence that children with one risk factor were more likely to be affected by the other.
Luckily, both of these risk factors are modifiable; a common cause of SDB is enlarged tonsils or adenoids, which can be removed through surgery, and parents can promote good sleep habits to lengthen sleep duration.
"We know that the road to obesity often begins early in life," says Prof. Bonuck. "Our research strengthens the case that insufficient sleep and SDB - especially when present early in childhood - increase the risk for becoming obese later in childhood."
"If impaired sleep in childhood is conclusively shown to cause future obesity, it may be vital for parents and physicians to identify sleep problems early, so that corrective action can be taken and obesity prevented. With childhood obesity hovering at 17% in the US, we're hopeful that efforts to address both of these risk factors could have a tremendous public health impact."
Though the study utilized a large sample size over a long period of time, it did not analyze whether children affected by both risk factors were at greater risk for obesity than children with just one risk factor, which could be a limitation.
Medical News Today recently reported on a study that suggested disruption to the sleep cycle may play a role in cancer development.