Plunge in preschooler obesity rate unlikely?

Not everyone agrees that the obesity rate among our nation’s preschoolers is dropping, as we reported earlier this month.

In the March 6, 2014, eConsult, we reported on a study conducted by researchers at the Centers for Disease Control and Prevention (CDC) who found that the obesity rate among 2- to 5-year-olds decreased 43%, from 13.9% in 2003-2004 to 8.4% in 2011-2012.

The CDC researchers themselves seemed surprised by the finding and had no real explanation for it. They surmised in their study that the finding may have something to do with childcare centers improving their nutrition and physical activity, the consumption of fewer sugar-sweetened beverages, improving breastfeeding rates, and/or First Lady, Michelle Obama’s “Let’s Move” campaign. They carefully concluded, “Overall, there have been no significant changes in obesity prevalence in youth or adults between 2003-2004 and 2011-2012.”

They knew the study had statistical limitations. Although the 2011-2012 version of the survey used included 9,120 participants, only 871 of them were aged between 2 and 5 years, a small enough sample size to have allowed for chance fluctuations.

The 13.9% obesity rate among preschoolers reported for 2003-2004 had a large enough margin of error that the actual rate could have been anywhere between 10.8% and 17.6%, and the 8.4% rate reported for 2011-2012 could have been anywhere between 5.95% and 11.6%. Because the ranges overlap, it is possible that there may have been no change, or even a slight increase, in the obesity rate, rather than such a steep decline.

Furthermore, experts say that other reputable studies do not support the finding. They agree that more data is needed for both preschoolers and older children to resolve the controversy.

To get weekly clinical advice for today's pediatrician, subscribe to the Contemporary Pediatrics eConsult.