Way Past Bedtime

What Do Late Bedtimes for Toddlers Tell Us About Obesity?

A new study this week in Pediatrics for the first time shows that children with late bedtimes have a higher risk of obesity. That association is even stronger if a child has parents with obesity. It’s not totally clear what this tells us – if anything – about cause and effect. But it’s reasonably clear what parents should do. That’s because healthy sleep patterns are important at every age.

Nicole Glaser authored a commentary with Dennis Styne to go with this study. She told HealthDay that causal relationships might be hard to define, but the recommendations about bedtimes are not:

An earlier bedtime for kids is absolutely a good idea. Parents can have some much needed quiet time and time together to recharge the batteries, so they can have more energy for their kids the next day.

A Small Study with Objective Measures

The findings of this study are solid because the researchers did not rely on parents to report sleep patterns. Instead, they collected objective data from activity monitors worn by the children. This eliminates bias that is so pervasive when collecting self-reports about health habits. People misremember things and offer reports that sound better than the messy reality of life.

But at the end of the day, it was still a small observational study. These data come from 107 Swedish children in an obesity prevention project. The study followed these children from the age of two until they turned six. Researchers collected data on sleep and adiposity annually throughout the study.

What Does This Relationship Tell Us?

Senior author Claude Marcus explains the problem of establishing causality:

This late bedtime was one factor that really stood out. It was associated with increased weight. However, what we can see is only an association. If you put your kids to bed earlier, would it change anything? That’s something we don’t know.

My personal hypothesis is that this is more of a marker of a more irregular life.

These questions are important. While earlier bedtimes might benefit children and parents in many ways, we can’t afford to assume that such good advice is also a good strategy for preventing obesity. We can’t assume that late bedtimes are a root cause of childhood obesity.

Making such assumptions is a surefire way to assure that we repeat past failures to find effective strategies for reducing the high prevalence of obesity.

Click here for the study and here for the commentary. For further reporting, click here and here.

Way Past Bedtime, photograph © Tormod Ulsberg / flickr

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February 19, 2020

3 Responses to “What Do Late Bedtimes for Toddlers Tell Us About Obesity?”

  1. February 19, 2020 at 7:57 am, Mary-Jo said:

    As with any other one thing associated with lower prevalence or incidence of obesity, early bedtime is not the magic bullet preventing childhood obesity. Whether late bedtimes point to a marker of irregular habits that could include snacking or increased low total nutrient caloric intake relative to a child’s needs, fatigue interrupting/lowering a child’s physical activity levels, and overall more sedentary time spent watching tv/computers, lack of quality sleep respecting dark:light periods also interrupts very important physiological processes related to cell growth and repair, circadian rhythm, hormonal function, brain development, digestive and metabolic functions which COULD increase risks for obesity to realize more assuredly in predisposed children.

  2. February 19, 2020 at 9:55 am, Allen Browne said:

    There you go – thinking again!

    Thank you.


  3. February 19, 2020 at 12:00 pm, David Brown said:

    Is this still another clue as to what is wrong with the food supply? Typically, researchers view problems associated with low levels of omega-3 or an omega-3/6 imbalance as a deficiency problem when, for all practical purposes, it is an excess of omega-6 problem. While supplementation can be helpful in terms of quieting excessive cell signaling, it makes more sense to reduce omega-6 intake.

    To date, there have been no moves to balance the omega-3/6 ratio or reduce the arachidonic acid content of animal products.