A new study suggests the majority of preschoolers may not be getting the amount of sleep they need each night.
Researchers believe the sleep deficits place the children at higher risk of being overweight or obese within a year. Investigators also suggest that some of the sleep inadequacies may be linked to how much a mother works.
University of Illinois investigators studied the relationship between mothers’ employment status and their child’s weight over time. Factors such as children’s sleep and dietary habits, the amount of time they spent watching TV, and family mealtime routines were analyzed to determine if they influenced weight gain.
The study has been published online by the journal Sleep Medicine.
“The only factor of the four that we investigated that mediated the relationship between maternal employment status and child obesity was how much sleep the child was getting each night,” said lead author Katherine E. Speirs.
Speirs and co-authors Janet M. Liechty and Chi-Fang Wu followed 247 mother-child pairs from the STRONG Kids study for a year. STRONG is a health awareness initiative for families that focuses on preventing child obesity.
The children, who ranged from three to five years old, were weighed, measured, and had their body mass index calculated at the outset of the study and again one year later.
At the second weigh-in, 17 percent of the preschoolers were overweight and 12 percent were obese, according to BMI-for-age growth charts.
In the study sample, sixty-six percent of the mothers were employed full time, defined as working 35 hours or more per week. Another 18 percent of the women were employed part time, or 20 to 34 hours per week.
The amount of time a mother worked made a difference in their child’s sleep and weight.
Investigators discovered children whose mothers worked full time got fewer hours of sleep than peers whose mothers worked less than 20 hours per week. The children of women who worked full time also tended to have higher BMIs at the second weigh-in.
Saliently, only 18 percent of the preschoolers in the sample were getting the 11 to 12 hours of nightly sleep recommended by the National Heart, Lung and Blood Institute. On average, the children were getting about 9.6 hours of nighttime sleep, say the researchers.
When children received the recommended amount of sleep, BMI was improved.
Investigators discovered each additional hour of nighttime sleep that a child obtained was associated with a 6.8 percent decrease in their BMI at the second weigh-in.
“We looked at nighttime sleep in particular, because studies show that the amount of nighttime sleep matters for regulating weight,” said Liechty, a professor of medicine and of social work.
“We think that it might be the more hours that mothers are working, the less time they have, and there may be some sort of tradeoff going on, ‘Do I spend quality time with my child or do we get to bed early?’” Speirs said.
“And then in the morning, when mothers leave for work, their children also wake up early to get to day care.”
Experts recommend the following sleep schedules:
- Newborns — 16-18 hrs
- Preschool-aged children — 11-12 hrs
- School-aged children — At least 10 hrs
- Teens — 9-10 hrs
- Adults, including the elderly — 7-8 hr.
Researchers recruited mothers whose children were enrolled in 32 licensed day care centers in Central Illinois. Sixty-six percent of the women had college degrees; about a third had household incomes under $40,000 a year, and just over half the sample had household incomes under $70,000 a year.
“The challenges of ensuring that children obtain adequate sleep may be even greater for low-income women, who often hold multiple jobs or work rotating shifts or nonstandard hours,” Speirs said.
“There are lots of characteristics about mothers’ employment that are really important to help us better understand the relationship between mothers’ employment status and child obesity,” said Wu, a professor of social work.
“Factors such as whether women are working part time voluntarily or involuntarily, or scheduled or nonscheduled hours make a difference.” Currently, the authors are exploring some of these characteristics and possible links with child obesity in a related study.
Source: University of Illinois