Pre-school children require an average of 11 to 12 hours of sleep in order to function properly throughout the day, according to the National Institutes of Health. Sleep-related disorders and lack of sleep are common discussions within childcare, with many parents worried about the risks they pose, including increased agitation, moodiness, and a reduced ability to concentrate on school work.

But lack of sleep and sleeping disorders extend far beyond these short-term factors, having been linked to higher risks for more severe consequences, including diabetes, cardiovascular disease, and shorter stature later in life. Obesity has been named as one of these long-term consequences in numerous papers and studies. Now, a new research paper focuses on the independent effects that lack of sleep and sleep disordered breathing have on obesity rates for small children later in life.

The paper, published in The Journal of Pediatrics, found that children from birth to almost 7 years old who showed the severe symptoms of sleep-disordered breathing were at high risk of becoming obese by the ages of 7, 10, and 15, while those around the ages of 5 and 6 who experienced short periods of sleep were likely to develop obesity by age 15, according to the study. Both findings are independent of one another.

"We know that the road to obesity often begins early in life," said Dr. Karen A. Bonuck, lead author of the paper and a professor of family and social medicine and obstetrics and gynecology at the Albert Einstein College of Medicine, in a press release. "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."

The Avon Longitudinal Study of Parents and Children, an observational study carried out at the University of Bristol in England, collected the data used as the basis for the paper by examining the sleep patterns and body mass index ratios of 1,899 children born in Southwest England between April 1991 and December 1992. Researchers focused on children from the time of their birth to almost 7 years old, reasoning that early childhood is a better predictor of obesity in pre-teen, teen, and early adolescent years and because excess weight gain takes place a lot at this time in life. The data was collected through questionnaires filled out by the parents of the participants.

All participants were examined for sleep-disordered breathing, with each one filed into clusters made up by three SDB symptoms: snoring, witnessed sleep apnea, and mouth-breathing. Questions included breathing through the mouth rather than nose, length of snoring time and appearance of not breathing or holding one's breath for a few seconds. Researchers found that those who scored the highest had the worst cases of SDB and were twice as likely to develop obesity by age 7 (when BMI begins to increase after early childhood), 10 (before puberty), and 15 (during puberty).

The study also found that children between the ages of 4 and 6 with the lowest amounts of sleep had a 60 to 100 percent higher risk of being obese by age 15. Those in other age groups with short sleeping periods showed no signs of risk. Those that were two and a half with the longest periods of sleep were less likely to become obese by age 15. The effects of both SDP and lack of sleep were examined independently of one another.

"These two risk factors had not been tracked together in children over time to determine their potential for independently influencing weight gain," Dr. Bonuck said in the press release. "Our study aimed to fill in that gap."

The exact causes behind SDB are complex, with scientists linking it to inflammation, sleep disruption, insulin resistance, and hormones that control hunger and appetite. SDB has also been linked to enlarged tonsils and adenoids, both of which can be removed surgically, though this is not always effective as adenoids are able to grow back in some cases. Parents who notice symptoms of SDB in their children are advised to see a doctor for treatment.

"There are a number of different approaches," Bonuck told Medical Daily. "The most important is for parents to be knowledgeable and alert to the sign of symptoms of sleep-disordered breathing."

She says that parents should also make sure their children are getting a proper night's sleep.

"They need a good routine," she told Medical Daily. "They need to go to bed on time. Things like that. That will promote good sleep."

Source: Bonuck K, Chervin RD, Howe LD. Sleep-Disordered Breathing, Sleep Duration, and Childhood Overweight: A Longitudinal Cohort Study. The Journal of Pediatrics. 2014.