Instilling healthy eating and exercise habits in children may help prevent obesity later in life. But which kids most need such obesity-prevention efforts? A recent study by Jeremy Goldhaber-Fiebert and colleagues at Stanford's School of Medicine showed that this question is harder to answer than it seems. The study, published earlier this year in Medical Decision Making, found that targeting obesity prevention to small children who are overweight might not be effective. That's because a higher-than-normal weight at age 5 provides an accurate predictor of adult obesity only 50 percent of the time.
Goldhaber-Fiebert, an assistant professor of medicine and core faculty member of Stanford Health Policy, discusses the problem.
What does your paper tell us about the recent focus on childhood and adolescent obesity measurements?
Our study has two take-home messages. First, while childhood obesity is an important problem, solving childhood obesity alone will not solve future adult obesity problems. Second, addressing future adult obesity will require broader societal measures — not simply interventions focused on obese children.
It used to be that no one worried much if a small child was chubby; the doctor might say, "It's baby fat, he'll grow out of it." How has that changed?
In fact, our data show that many children still do "grow out of it." But our findings suggest that it is difficult to predict whether this will happen for a specific child. Consequently, efforts to help obese children must be connected to broader efforts to create healthy diets and habits for all children.
Childhood obesity is concerning both because it presents increased health risks for individuals while they are children and also because of the fear that it will translate into serious adult obesity-related health issues. Our analyses show that targeting children who are already obese is unlikely to be sufficient in addressing broader public health challenges of obesity in later childhood, adolescence and adulthood.
Are there other more promising screening criteria for chronic adult obesity instead of using a child's weight?
It really depends on the purpose of screening. Researchers have identified a variety of characteristics to predict a child's future obesity status — for example, easily observed measures like the weight of a child's parent as well as more complex measures such as their size at birth and the rapidity with which they subsequently grew and gained weight.
The challenge is to have a measure that both does not miss a substantial fraction of those who become obese later on and also does not falsely predict obesity for a large number of those who do not become obese as adults. The trade-off between these two types of errors depends on the seriousness of health implications of obesity and the costs of treating health conditions once they arise, as well as the health and economic costs of delivering preventive interventions to people who are identified as being at risk of becoming obese regardless of whether they become obese in the future.
What are some of the best potential approaches for reducing childhood obesity if the entire population is being targeted?
Given that many health-related habits are developed in childhood, efforts to create healthy eating and exercise habits in children would seem to be beneficial. But for most potential interventions, we lack evidence of their widespread effectiveness over a long period of time. Do reductions in obesity persist from childhood into adulthood? Do they lead to measurable improvements in health outcomes? We do not have answers to these key questions.
Food, beverage or sugar taxes and other manipulations to food prices or availability may be effective, but may also have unintended harms and certainly come at the cost of curtailing personal choice. Re-engineering the built environment or nudging people with various behavioral/economic mechanisms have garnered attention though, again, widely generalizable evidence on them is lacking. The problem deserves continued creativity and ongoing evaluation and testing.
Your paper focuses on which obese children will become obese adults, yet we are seeing a growing number of children experiencing type-2 diabetes and other negative health consequences of being overweight before they're even out of their teen years. Is adult obesity the best endpoint to focus on?
Obesity-related conditions of childhood clearly should not be ignored. What we are concerned about is the sense that people were conflating good care for children to deal with their shorter-term health needs (i.e., childhood obesity management to deal with childhood health issues) and the belief that such an approach might largely solve the broader adult obesity issues. Addressing childhood obesity is still important even if it does not fix adult obesity and its deleterious health consequences.
Erin Digitale is the pediatrics writer for Stanford School of Medicine's Office of Communication and Public Affairs.