The development of childhood obesity is complex and complicated. While it is difficult to point to one thing that accounts for childhood obesity (which makes it very similar to adult obesity), there are also no simple solutions.
Nevertheless, it is certainly important to understand if there are indeed factors that are associated with the increased risk for childhood obesity – especially risk factors that can potentially be ameliorated.
This was the subject of a paper by Sylvana Cote and colleagues from the University of Montreal, just published in the Archives of Pediatric and Adolescent Medicine.
The researchers studied the developmental trajectories of BMI in early childhood in an 8-year longitudinal study consisting of a representative sample of over 2000 children selected through birth registries for the Quebec Longitudinal Study of Child Development.
Three trajectories of BMI were identified: low-stable (54.5% of children), moderate (41.0%), and high-rising (4.5%).
The high-rising group, characterized by an increasing average BMI, which exceeded international cutoff values for obesity by age 8 years, was associated with two maternal risk factors: maternal BMI (with a 6-fold higher odds ration if the mother was herself obese) and maternal smoking during pregnancy (odds ration 2.28).
If these risk factors are indeed causally linked to childhood obesity (and not just surrogates for other aspects of maternal or family behaviour), then they may be amenable to intervention. Clearly, not smoking during pregnancy should by now be something that everyone should realize bears risks for both mother and offspring (and not just risk for obesity).
How to better manage weight before and during pregnancy will likely prove to ba a far greater challenge.
However, as the authors point out:
“Children continuing on an elevated BMI trajectory leading to obesity in middle childhood can be distinguished from children on a normative BMI trajectory as early as age 3.5 years. Important and preventable risk factors for childhood obesity are in place before birth.”
This means that the most effective approaches to preventing childhood obesity may well precede the birth of the child – once born, not dissimilar to managing adult obesity, all interventions are likely to be palliative.
Pryor LE, Tremblay RE, Boivin M, Touchette E, Dubois L, Genolini C, Liu X, Falissard B, & Côté SM (2011). Developmental trajectories of body mass index in early childhood and their risk factors: an 8-year longitudinal study. Archives of pediatrics & adolescent medicine, 165 (10), 906-12 PMID: 21969392