Tuesday, September 27, 2011
Poor Infant Sleep does not Increase Later Obesity Risk
With childhood obesity rates at epidemic levels in developed countries around the world, there is great interest in identifying successful interventions to decrease obesity risk. Recently, researchers have suggested a potential association between poor sleep and later obesity risk. Today we’ll discuss this potential association and present information from a new study examining the association between improved sleep in infancy and obesity risk at age 6 years.
In a previous post we wrote about a research article linking short sleep duration to increased risk of obesity. (Bell 2010) In this study, the association found was not specific to infants because the authors grouped together kids of all different ages.
Sleep and Obesity: Why the Link?
Despite all of the research about the relationship between sleep and obesity, there is no evidence showing a cause and effect relationship. Researchers have theories for the associations they’ve found, including: (1) if children are sleeping less, their bedtimes may be later allotting them more time to take additional calories in the evening or (2) children may be less physically active because of fatigue from shorter sleep duration. Unfortunately, at this time, these explanations are just speculation and while some studies have shown associations between BMI and chronic short sleep in older children, none have focused on how sleep in infancy may or may not affect later risk for obesity.
In a recent Australian study, providing education to parents of infants with parent-reported sleep “problems” at 7-8 months resulted in improved infant sleep organization but did not reduce obesity risk at age 6. (Wake et al. 2011) A Sleep “problem” was identified by asking 2 questions: (1) “Over the last 2 weeks, has your baby’s sleep generally been a problem for you? (yes/no)” and (2) if yes, the parent rated the severity of the problem on a 7-point scale with 1-2 mild and 5-7 severe.
The Study Intervention
Nurses were trained to provide a short sleep education to parents at the 8-month well-child check-up. Topics discussed included normal infant sleep patterns and sleep problems and potential causes. Nurses helped parents to identify possible solutions and created an individualized sleep management plan for each family. Mothers were asked to complete a 2-week sleep diary and to choose one of two sleep strategies: “controlled crying” or “camping out.” Mothers also attended 1-2 follow up sessions with the nurse where sleep patterns and improvements were identified and new goals were set.
The controlled crying strategy involved parents responding to their infants’ cries at increasing time intervals to allow the infant to learn to self-soothe. (see note below) Parents choosing the “camping out” strategy were instructed to initially stay with the infant while he or she fell asleep, slowly moving farther away over the following days, until the infant could fall asleep without the parent nearby.
Results of the Intervention
Parents in the intervention group reported fewer infant sleep “problems” at 10 months (56% vs. 68%) and 12 months (39% vs. 55%) compared to control groups. Intervention parents also reported fewer and shorter night-wakings than control parents. However, sleep duration was similar in both groups.
Although the sleep intervention did decrease parent-reported “sleep problems” and night wakings, there was no effect of the intervention on obesity at age 6. Both intervention and control groups’ BMI and waist circumference were similar. After the study was completed, the researchers looked back at the data to see if there was any association between childhood sleep duration and BMI. They found no association between sleep duration at 7, 10, 12 months or 6 years with obesity at age 6.
The Bottom Line:
According to recent data, your baby’s sleep patterns at night will likely not affect his risk of obesity in later childhood. We know (from experience) that some of you may be very tired right now and hoping for a solution to help your baby sleep better. Our best advice: know what to expect from your baby’s sleep patterns by reading our posts about how sleep patterns change with age and learn some ways to get yourself a little more rest.
Remember, you can’t change the rate at which your baby’s body matures and learns to sleep for longer stretches, but you can change how you react to it! Arm yourself with the knowledge and know that this too shall pass.
Note: We are not advocating letting your baby cry! We are simply reporting the methods used by the authors of the referenced study. Also, it is important to note that this intervention was carried out with older infants, ages 8-10 months; most infants this age have the ability to sleep a 6-8 hour stretch at night, but they may wake if they need something or to practice their new found motor skills.
While we do not advocate parents letting their babies cry for long periods, also known as the “cry it out” approach, parents of older babies can encourage them to learn self-soothing skills. For example, putting your baby to sleep in his crib drowsy, but awake may help him learn to soothe himself to sleep. However, keep in mind that, in a separate study, only about half of 12 month olds were able to self-soothe after awakening during the night. The other half needed their parents’ help to get back to sleep. (Burnham et al. 2002)
1. Bell J, Zimmerman F. Shortened Nighttime Sleep Duration in Early Life and Subsequent Childhood Obesity. Arch Pediatr Adolesc Med 2010; 164: 84-845.
2. Wake M, Price A, Clifford S, Ukoumunne OC, Hiscock H. Does an Intervention that improves infant sleep also improve overweight at age 6? Follow-up of a randomized trial. Arch Dis Child. 2011;96:526-532.
3. Burnham MM, Goodlin-Jones BL, Gaylor EE, Anders TF. Nighttime sleep-wake patterns and self-soothing from birth to one year of age: a longitudinal intervention study. J Child Psychol Psychiatry. 2002;43(6):713-25.