THE BLOG

Pediatric Obesity, Ping-Pong, and Puzzle Pieces

08/12/2013 10:33 am 10:33:28 | Updated Oct 12, 2013

Among the salient items of medical news this week -- particularly salient, perhaps, for the editor-in-chief of Childhood Obesity, but rather important for anybody who knows a kid or has ever been one -- was a report by the CDC that obesity rates had declined among the very young and poor in 19 of 43 states and territories for which data had been collected. Specifically, the report pertains to children ages 2 to 4 in households eligible for food assistance in the WIC program.

At first blush, this is clearly a glass half full. My colleagues and I who are dedicated to this issue have been chronicling the relentless increases in obesity rates for decades. Against the backdrop of constantly grim news, even the absence of more grim news is cause for temperate celebration. We have started to hear over recent years about a possible plateau in the rates of obesity among children and adults alike, and about declines in specific locations and settings, notably those sites most dedicated to confronting the problem.

But poverty is a risk factor for obesity (not that affluence reliably defends against it -- just look at the high-profile weight struggles of the rich and famous), so news of a decline in obesity rates among WIC households is particularly noteworthy. It suggests that we may be better defending the most vulnerable from one of the most prominent scourges of modern epidemiology.

But before we take a glass half full and hoist it in an exuberant toast to our success, we might pause to consider the half-empty portion. There are some precautionary messages in the lines of this report, and even more such between those lines, and beyond them.

In the lines we have the news that while obesity rates declined among the very young in 18 states and the U.S. Virgin Islands, they did not decline in the other 24 states and territories included in the analysis. That's a success rate of 44 percent, which would qualify for a "F" if this were an academic exercise. Obesity rates -- despite all the attention to them -- remained constant in 21 of the sites, and actually increased in the remaining three.

The new report also indicates that the steepest decline in obesity prevalence seen anywhere, and it happened to be offshore in the U.S. Virgin Islands, was 2.6 percent. In most cases, even when obesity rates fell, they fell by a fraction of a percentage point; the decline was 1 percent or more in only six of the 19 sites reporting good news. That's still good news, of course, but it's very modest good news -- and perhaps falls well short of the threshold for releasing balloons and confetti.

Then there's the fact, also in the lines of the report, that these were families enrolled in CDC's Pediatric Nutrition Surveillance System. That may not have implications in this case. But in general, we know that participation in studies tends to alter behavior. In particular, participants in programs that monitor diet, exercise, and/or weight tend to do better in these areas -- even without any intervention -- than counterparts not participating in such studies. Partly, this may be because more health conscious people are favorably disposed to enroll in studies like these in the first place, while the less health conscious are not. It may be because interaction with investigators asking questions about diet, for example, tends to encourage better eating. It's probably a bit of both.

The relevance in this case is that maybe obesity rates only actually declined among participants in the survey, rather than for the larger populations they are supposed to represent. We don't know that this is true, but we know it tends to happen, and can't know it isn't true based on the information here.

And there is also the possibility that stabilization in obesity rates has something to do with the fact that everybody vulnerable to obesity is already a victim of the epidemic. Some experts have offered up that very explanation to account for the current study, but while it might help explain a plateau, it doesn't really account for a dip. Still, the "we can't go up because we've hit the ceiling" argument may be part of the full accounting for current trends.

Then there are the even more important precautions that reside outside the lines of the new study altogether. One very flagrant one is the recent report, which also made headlines during its 15 minutes in the spotlight, that while overall rates of obesity are leveling off, rates of severe obesity are "skyrocketing." That suggests that we no longer get all the information we need about the state of the obesity epidemic by assessing how many of us are overweight; rather, we may need to be looking more closely at how overweight the many of us are.

We have had recent news about the ominously rising rate of diabetes. We have heard about the particular severity of Type 2 diabetes in children. We have heard about the rising prevalence of hypertension in kids. We have even heard about the rising rate of stroke among children 5 to 14.

None of this goes away when this week's report offers a glimmer of hope, and my hope is that we really do understand that. The media, in the business of getting noticed, practice the art of comforting us when we are afflicted, and afflicting us when we are too comfortable. That practice tends to treat science like a Ping-Pong ball, with the current version of truth batted in one direction last week, another this week. We play Ping-Pong with science at our collective peril, and I advise strongly against it -- whatever the "news of the day" may invite.

A far more useful construct is a puzzle. Science is incremental and comes together piece by piece, as puzzles do. Every piece is a part of the big picture; no single piece defines the big picture, or displaces all the pieces that came before. Slowly, we aggregate a reliable image of the truth. When we substitute today's titillating headlines, whatever way they may point, for the incremental aggregation of genuine understanding, there is a very real risk of paying for it in lives.

What, then, does the puzzle of pediatric obesity look like now? It looks to me like a glass with at least the promise of being half full at long last, but still clearly at least half empty. The picture suggests, encouragingly, that widespread attention to the crisis of childhood obesity can make a difference, and is seemingly starting to do so -- for some of the kids in some of the places at least some of the time.

But it also shows that millions of kids have already been caught up in this crisis, and the dangers they face aren't going away any time soon. We have a lot of childhood obesity to treat -- including the severe forms most refractory to most forms of treatment. We have a rising tide of chronic disease risk factors among ever-younger children. We have the increasing prevalence of Type 2 diabetes in children. And even in the new report, where the news is good, we have a failure to move the needle favorably in more than half the sites surveyed, despite all that is being done to contend with childhood obesity, including a campaign spearheaded by the First Lady herself.

So while I like the good news as much as anyone, my advice is to set down the champagne glass and Ping-Pong paddle alike. Let's get right back to work, looking for the puzzle pieces required to give us a picture of a glass full up to the brim.

-fin

Dr. David L. Katz; http://www.davidkatzmd.com/

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