Obesity rates drop for poor preschoolers, but race disparities persist

Health reporters aren’t accustomed to having good news to report on the childhood obesity front, so it was welcomed relief Tuesday when the Centers for Disease Control and Prevention announced that the prevalence of obesity among low-income preschoolers dropped in 19 U.S. states and territories over a three-year span.

The findings, drawn from the years 2008-2011, are particularly newsworthy given that preschool obesity has doubled in recent decades: An estimated one in eight preschoolers is now obese in the United States, according to the CDC, or about one in seven in low-income kids. Among the states and territories that reported drops in obesity in low-income preschoolers, Georgia, Florida, New Jersey, South Dakota, Missouri and the U.S. Virgin Islands led the pack, with drops of 1 percent or more.

But the modest dips in obesity rates didn’t extend nationwide. Puerto Rico joined 20 other states in which there was “no significant change,” while Colorado, Tennessee and Pennsylvania actually notched increases in obesity prevalence.

The new data on preschoolers is significant because early childhood plays an outsized role in determining whether a kid will grow up to be obese or overweight. “Overweight or obese preschoolers are five times as likely as to become overweight or obese adults as their non-obese peers,” the CDC report notes.

As the New York Times reported in its coverage, there have been sporadic reports of declining childhood obesity rates trickling in over the past couple years:

Several cities have reported modest drops among school-age children, offering hints of a change in course. But gains were concentrated among whites and children from middle- and upper-income families, and were not consistent across the country.

This week’s report, based on weight and height measurements from 11.6 million low-income kids ages 2-4, spread out across 40 states, the District of Columbia, and two territories, offers a far more comprehensive picture with new evidence that the dips in obesity are real and that they extend to low-income preschoolers.

But as the CDC acknowledged in its report, it’s not immediately clear why the rates are dropping in places. The report ventures some possible explanations, but they remain safely vague: State and local nutrition and exercise programs, changes in federal food benefit programs, increased breastfeeding, media coverage boosting awareness, community initiatives, and so forth. Anecdotally, the parents the Times talked fingered rising awareness: “In interviews, parents suggested that they have become more educated in recent years, and so are more aware of their families’ eating habits and of the health problems that can come with being overweight.”

The Washington Post’s coverage zeroed in on the possible role played by Women, Infants and Children, a federal program which offers food benefits and nutrition education to low-income women and kids:

Marlene Schwartz, director of the Rudd Center for Food Policy and Obesity at Yale University, said the 2009 changes in the WIC program likely played a large role in the progress. The program was altered to encourage purchases of fresh fruit and vegetables instead of juice, as well as whole-grain products and lower-fat dairy foods. “The changes in WIC were massive,” said Schwartz, who studied how the changes led more grocery stores in low-income neighborhoods to stock healthier foods.

It’s an intriguing bit of speculation, but given that the data the CDC used in its report covered 2008-2011, wouldn’t WIC policy changes instituted during 2009 take at least a year or two to deliver measurable changes, assuming there were any? What about the 2008 and 2009 data?

Study Looks at ‘Widening’ Racial Disparities

If the good news is that overall obesity rates appears to be dropping in parts of the country, the bad news is that there are still large disparities between racial groups. According to the CDC report, 12.1% of children ages 2 to 5 were obese during the years 2009-10. But that rate jumps to 16.2% for Hispanic children and 18.9% for non-Hispanic blacks.

Why then are obesity rates significantly higher among black and Hispanic children? A new study from Harvard Medical School researchers suggests that one of the main reasons is that children in these minority groups are exposed to more early-life risks than their white peers.

The study, published this month in JAMA Pediatrics, followed a cohort of 1,116 mother-child pairs in eastern Massachusetts from early pregnancy through age 7. Throughout the study, researchers tracked height and weight, waistlines and body mass indices, all while gathering data on family behaviors and risk factors.

Compared to the white kids in the study, the black and Hispanic children typically had higher Body Mass Index scores, higher body fat, and were more likely to be overweight or obese by age 7. “We found that the prevalence of overweight and obesity among black and Hispanic children at age 7 years was almost double that in white children,” the study says.

After crunching the data, the researchers found that the disparities couldn’t be explained by socioeconomic differences (or the parents’ obesity) alone. But they did find that “all the early life risk factors we measured were more prevalent among blacks and Hispanic children than among non-Hispanic white children.” When differences in early childhood “risk factors” were controlled for, the differences in obesity largely went away.

The risks the researchers identify largely fall into the behavior category:

These factors include differences in modifiable early feeding behaviors, such as breastfeeding and timing of the introduction of solid foods, accelerated infant weight gain, and early childhood obesity-related risk factors, including insufficient sleep, the presence of a television set in the room where the child sleeps, and consumption of sugar-sweetened beverages and fast food, all of which have been found previously to be more prevalent among blacks and Hispanics than among whites.

One of the ideas here is that these “risk factors” are “modifiable” behavior patterns that can be changed, as opposed to some innate biological characteristics or genetic predisposition. (It’s worth noting here that the researchers don’t venture into the far more sensitive subject of why these risk factors are more prevalent among these minority groups, when socioeconomic differences, like “parent's income" or "mother's education level,” have already been accounted for.)

“Our study implies that interventions to modify earlier life risk factors may greatly reduce disparities in the prevalence of childhood obesity,” the authors write.

Whether they’re called interventions, awareness campaigns, or parent education, programs that target obesity-prone behaviors may go some way in reducing racial or ethnic differences in childhood obesity rates. But as health disparities researchers such as Thomas LaVeist and others have pointed out, the broader context of neighborhoods and the effects of place shouldn’t be overlooked in the behavioral push.

“Places with high concentrations of black or Hispanic residents tend to be places characterized by limited opportunity and failing infrastructure, which results from a lack of investment in social and economic development,” write LaVeist and his colleagues in a 2011 report on the link between racial segregation and health inequalities. “The results are communities and neighborhoods which produce bad health outcomes.”

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