Along with many other media outlets, MSNBC reports on a study in the American Journal of Health Promotion which found that that 32% of 7,500 babies studied were overweight or obese by the time they reached 9 months old, and that 34% were overweight or obese by age two. It’s a shocking finding on its face, and one that’s getting lots of attention, but I’m having some trouble parsing it. (I don’t have access to the actual study, so I’m drawing from various media reports).
For one thing, the study found that there was quite a bit of fluidity in weight among this young age group; some of the heaviest infants had lost their excess weight by age two, while some of the thinner babies had gained weight by toddlerhood.
The L.A. Times provides more detail:
- Boys were more at risk than girls (this contradicted earlier research).
- Latinos had the highest risk.
- Geographic location was not consistently associated with being obese or at risk.
- The family’s socioeconomic status didn’t seem to make a difference at 9 months of age. But by two years, the kids in the bottom economic 20% were most likely to be obese or at risk, while those in the top 20% were least likely to be obese or at risk.
Yet according to this site, the investigators concluded that:
the study shows no relationship between infant or childhood obesity and adult obesity. However, the relationship between higher percentile weights in babies seems to greatly increase the risk of childhood obesity.
That last quote is encouraging on its face, but how can it be true that there’s no relationship between childhood obesity and adult obesity?
Another question — since all of the infants studied were born in 2001 and part of a cohort that was followed through kindergarten, why didn’t the investigators look beyond age two, so we could see how many of these overweight or obese babies and toddlers carried their excess weight to age five or six? That would provide more proof that being overweight at age nine months or two is of real concern, as opposed to a developmental blip.
I’m not minimizing the very real problem of childhood obesity, and having a baby or toddler in the 95th percentile for weight (which the investigators used as the measure of obesity) is a red flag that shouldn’t be ignored by parents or pediatricians. But it seems like this study raises as many questions as it answers.
[Hat tip: Donna Gershenwald]