Numerous studies have suggested that reduced sleep in children is linked to the increased risk of obesity. A new study, published in the journal Pediatrics, becomes the most comprehensive study, indicating that children who consistently had reduced sleep in early childhood went on to have increases in obesity, or overall body fat by the age of seven.
Most previous studies have not examined the effects of continuous sleep deprivation throughout time and have only used the body mass index (BMI) as a measuring tool for obesity. The new study, from Massachusetts General Hospital for Children, used data from Project Viva, a long-term investigation of several factors that affect the health of children during pregnancy and after birth.
Project Viva gathered its data from in-person interviews with mothers when their children were 6 months, 3 years and 7 years old, and from questionnaires completed by the mothers when their children the ages 1, 2, 4, 5 and 6 years old.
The mothers were asked their children’s sleep time, both at night and in the daytime. When the children were aged 7, the researchers also took measurements of height, weight, total body fat, abdominal fat, lean body mass and waist and hip circumferences. The researchers thought that these measurements would be a more accurate way of measuring cardiometabolic health risks than just measuring BMI.
As part of the study, each child was assigned a "sleep score" - from 0 to 13 - based on the mothers’ reports. The researchers discovered that the children with the lowest sleep scores had the highest levels of body measurements reflecting obesity. This link was found to be reliable at all ages, and does not seem to have a “critical period” when the interaction between sleep and weight has the greatest effect.
“Our study found convincing evidence that getting less than recommended amounts of sleep across early childhood is an independent and strong risk factor for obesity and adiposity”, says lead author Dr. Elsie Taveras.