During a year of Head Start preschool, obese and overweight children were much more likely to slim down than comparison groups of kids.
The study involved almost 44,000 preschool-aged children in Michigan and the researchers, from the University of Michigan, acknowledge it has weaknesses. But they say the potential benefits are important because obesity is so hard to treat and affects low-income children disproportionately.
Five things to know about the research, published online Monday in Pediatrics:
Head Start is a federal pre-kindergarten program offered free in every state to low-income families. It often involves full-day preschool, focusing on school readiness, healthy eating and physical activity. Many programs provide children two daily meals, and give families health and nutrition advice. More than 1 million U.S. children participate.
Almost 44,000 children participated, including about 19,000 Head Start kids. They were compared with children from Medicaid families and with those from wealthier, privately insured families. Health records and Head Start data provided height and weight measurements between the ages of age 2 and 6.
About 16 per cent of kids entering Head Start were obese, versus 12 per cent of Medicaid kids and 7 per cent of the others. After a year, almost 11 per cent of initially obese Head Start kids became normal weight, compared with none of the Medicaid kids and less than 2 per cent of the others. The improvements lasted through the end of the study, or when the kids entered kindergarten.
Similar trends were seen in kids who started out overweight but not obese.
Nationwide, about 8 per cent of preschoolers are obese, but the rate was mostly higher during the 2005-13 study.
The study found a reverse benefit for underweight children. Those in Head Start were more likely to gain weight and achieve a healthy weight after a year than other underweight kids.
The Head Start group had fewer blacks and more whites than the Medicaid group; the non-Medicaid group had the fewest number of minority kids.
A more rigorous test would have compared more similar groups, randomly assigning only some children to attend Head Start. That would be unethical because of Head Start's educational benefits, said lead researcher Dr. Julie Lumeng. It's likely that many kids in the comparison groups attended some kind preschool, perhaps including Head Start. That means it's not certain that participation in Head Start explains the weight improvements, she said.
But Dr. David Ludwig, a Harvard Medical School pediatrics professor and director of an obesity prevention centre at Children's Hospital Boston, called the results are impressive and encouraging despite the limitations.
He said the researchers chose a "very reasonable" alternative study design, and that the results make sense, given the services Head Start programs provide.
Head Start: http://tinyurl.com/l9zpznk
AP Medical Writer Lindsey Tanner can be reached at http://www.twitter.com/LindseyTanner