Childhood obesity has reached epidemic proportions, and has moved beyond public health discourse and onto the public stage. No doubt, efforts to prevent and treat childhood obesity are critical. But in the face of highly visible social campaigns -from school lunch reform to the elimination of “food deserts,” it can be tough to tell where medical knowledge ends, and common sense begins.
Here’s what we do know: First, childhood obesity is a big problem-in the US, 16.9% of children and adolescents age 2 to 19 years of age are estimated to be obese. We also know that obese children are likely to go on to become obese adults. We know that risk factors for cardiovascular disease such as hypertension, dyslipidemia, and insulin resistance, are already present in obese children. And finally, we know that childhood obesity is associated with an increased risk of an adult cardiovascular event.
But what we didn’t know, at least not until today, is whether childhood obesity confers a lifetime of increased cardiovascular risk, or whether this risk can be attenuated if obese kids become normal-sized adults. No one is about to object to efforts to combat childhood obesity, but knowing whether childhood obesity predicts adult cardiovascular risk, independent of adult BMI, is critical to shaping our efforts moving forward. Now some clarity may be coming our way.
In today’s issue of the NEJM, Juonala et al. publish their results from 6328 subjects, who averaged 11.4 years of age at baseline, and were prospectively followed for a mean 23 years. The good news? Obese children, who become nonobese by adulthood, have the same cardiovascular risk profile as adults who were never obese.
The study authors looked at four cohorts of children from the US, Australia, and Finland. The primary outcomes assessed were the presence of diabetes, hypertension, dyslipidemia, and high-risk carotid intima-media thickness. There were 274 obese children who went on to become nonobese adults.
As would be predicted from previous studies, childhood overweight or obesity was associated with overall increased cardiovascular risk, with some variation in the individual parameters within each cohort. However, in the group of obese children who went on to become nonobese adults, the cardiovascular risk profile was similar to that in the group of nonobese children who went on to become nonobese adults.
The unfortunate corollary is that being a nonobese child does not protect you if you go on to become an obese adult. For example, obese adults, regardless of childhood adiposity status, have a risk of type 2 diabetes that is four times that of nonobese adults.
Before we all jump on the no-cookie-bandwagon, a few caveats. First, these data are observational, and give us no information about cause and effect, nor on how weight loss was achieved. The outcomes assessed are risk factors, rather than hard endpoints like cardiovascular events. The number of obese children who went on to become nonobese adults was quite small compared to those who either stayed obese, or equally concerning, became obese. Finally, most of the subjects enrolled were white, and it is not clear how well these findings would apply to children of other ethnic groups, many of whom are affected by this obesity epidemic.
All that said, given the magnitude of this epidemic and its potential consequences, these results are at least somewhat encouraging. Now, how to help more obese children become nonobese adults? Let’s move indeed.