Recently the Otago Daily Times (and the NZ Herald by extension) published this article: Sleep lessons halve obesity rates in children. Eye catching isn't it? Well we took issue with the title and the reporting as well as the study itself. In response we wrote a letter to the editor which they declined to publish as they felt the criticism should be directed to the researchers.
We disagreed so have published the letter below:
Letter to the Editor
With regards to your article entitled Sleep Lessons Cut Obesity, published on Wednesday 8 March, I am concerned about both the misleading headline and quality of research promoted in the article.
I am a fully qualified senior nurse with a Masters in Health Science. I am also a co-founder of The Baby Sleep Practitioners, providing specialised advice to families about baby sleep, feeding and emotional needs.
Overall, the study the article references was poor quality and the methodology was inappropriate for the study design. Thankfully, this has been acknowledged by the investigators.
1. It was very disappointing to hear that health professionals providing advice in sleep education group discussed outdated methods, for example: putting new-born babies down to sleep while awake without using any settling techniques; feeding in a dark area and the use of extinction methods in some cases.
2. Even though the results between the 3 groups were statistically insignificant with no difference in sleep quality or duration it was still reported that the sleep intervention group had reduced obesity. This minor difference 0.4kg weight/0.7cm length could be explained as subject bias - parents are likely to record results inaccurately, either unintentionally or intentionally.
Sleep deprivation resulting in poor memory unintentionally skewing data or by recording more activity, less unhealthy food and less wake ups intentionally to make themselves feel better about their situation through their own self believe.
The investigators did acknowledge that the non-sleep intervention control group could not be isolated from external sleep advice – it would be impractical and unethical. This includes strong influential routes such as sleep consultants, social media, the internet, magazines and well-meaning friends and family.
3. Progression of developmental milestones is one of the many factors that seems to be overlooked in this study. For example a baby learning to crawl or walk would clearly have a direct effect on BMI especially given the wide range of what is accepted as developmentally appropriate.
4. I agree that obesity is becoming a problem in preschool children and that the evidence suggests that an overweight pre-schooler leads to an overweight adult. This is of concern due to the associated poor health outcomes, for example the increased risk of heart disease and type 2 diabetes. However formula fed and breastfed infants need to be treated differently without perpetuating mother blame in society around how we feed our babies. It is inappropriate to be labelling a breastfed infant as overweight. A breastfed baby cannot be overfed as any excess weight is required to sustain a baby through periods of illness when ones immune system is developing. This excess weight will be latter lost if the toddler leads an active lifestyle with a diet consisting of variation that is quantity controlled by the baby preferably through self-regulation of sleep and appetite. Therefore, a mother should never feel guilty about putting her baby to the breast for any reason.
Formula fed babies are less likely to lose excess weight gained in infancy and education should be focused on paced bottle feeding and encouragement of babies to feed themselves solid foods with the aim of slowing down the rate at which they eat. The rate and which a baby eats is an important part of developing self-regulation but also will ensure a baby still grows to its genetic potential. If this study or a similar study was to be repeated in future I would advise that the rate at which a baby eats should be an area that needs to be focused on.
There are too many weak areas in this study – before the results can better stand up to scrutiny and peer review, conclusions should not be drawn and promoted.
Amy Sherpa, RN, MHlthSc (Nursing)
The Baby Sleep Practitioners®
Specialised nurses for your baby’s feeding, sleeping and emotional needs
Amy and Elspeth