Speculating About COVID-19 and Childhood Obesity

The headlines are pretty direct about it. “COVID-19 lockdowns make childhood obesity worse,” says a headline from the University of Buffalo. Another report tells us that school closures will drive childhood obesity rates up by 2.4 percentage points. All this sounds very precise and matter of fact. But what it really amounts to is speculation. Or hypotheses. Not facts.

In fact, we have no data whatsoever on the prevalence of childhood obesity during the COVID-19 lockdown. Not yet.

Reports from Parents About Eating and Physical Activity

The study that fueled the headline about obesity from Buffalo was about behaviors. No measures of obesity. The data comes from a cohort of families in Verona, Italy. It’s actually a helpful study, because it analyzes what parents reported their children doing during the lockdown. In addition, it offers a comparison to what those same parents reported their children doing one year prior to the lockdown.

But it’s a study of behaviors, not obesity. The authors of this study are quite clear. “We do not have post-confinement measures of BMI,” they wrote. What they have are parents reporting unfavorable changes in dietary habits, more sleep time, and more screen time. Will these changes net out to cause more obesity? The authors speculate that they might.

Two Earlier Papers

Two earlier papers also offered speculation that childhood obesity might rise during the COVID-19 pandemic.

The first was an opinion paper by Andrew Rundle and colleagues. They note that prior studies have shown a correlation between time out of school and excess weight gain. They go on to say that COVID-19 school closures make other risk factors for childhood obesity worse. These include screen time, physical activity, and nutrition. They offer a call for vigilance to prevent adverse outcomes. Not data on obesity prevalence.

The second paper lays out a model of how COVID-19 might affect childhood obesity rates in the U.S. The assumptions going into this model yielded as much as a 2.4 percentage point increase in prevalence. They projected the biggest increases for boys, Blacks, and Hispanics.

Equating Obesity with Behavior

The common thread in all of this is a fundamental assumption – that behavior drives obesity prevalence. But the truth is that obesity results from a more complex web of many factors that adapt and interact with each other. Though many factors correlate with obesity, the evidence for causality is a bit more wobbly.

Given that childhood obesity has been growing for three decades, predicting that it will grow during the pandemic lockdown is probably a safe bet. But predicting a big spike is more speculative.

So we would do well to avoid confusing speculation with facts and to remember that behaviors don’t explain everything about obesity.

Click here for the study of behaviors in Verona, here for the perspective from Rundle et al, and here for the model projecting U.S. childhood obesity rates.

Cats Speculate, photograph © sally / flickr

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June 8, 2020