Toddlers who have poor relationships with their moms are more likely to pack on extra pounds as they grow up, a new U.S. study shows.

Tracking nearly 1,000 kids into their teens, researchers found more than a quarter of those who scored lowest on mother-child relationship tests as toddlers went on to become obese at age 15.

By contrast, only 13 percent of the children who had a good relationship with their mother became obese.

While that doesn’t prove cause and effect, researchers say other work has shown links between children’s emotional and intellectual development and how they interact with their mother at a young age.

According to Sarah E. Anderson, who worked on the new study, it’s possible that a stressful childhood could make a lasting impression on kids’ brains.

“There is an overlap in the brain between the areas that govern stress and energy balance,” said Anderson, of the Ohio State University College of Public Health in Columbus. “This stress response could be related to obesity through appetite regulation.”

Dr. David Gozal, a pediatrician not involved in the new work, agreed. But he said unhealthy food and a lack of physical activity and sleep are likely to play a bigger role.

Still, he said, early childhood stress is known to take a toll later in life—both via genetic reprogramming and behavioral changes—and a poor mother-child relationship could be part of the equation.

“What you see in adulthood is obviously the cumulative effect of what has happened earlier in life,” Gozal, physician-in-chief at the Comer Children’s Hospital in Chicago, told Reuters Health.

Anderson’s findings, published in the journal Pediatrics, are based on 977 kids who were videotaped while playing with their mother at about one, two and three years of age.

Researchers then assessed the toddler’s relationship to their moms based on the mother’s ability to recognize her child’s emotional state and respond with warmth as well as the child’s tendency to freely explore its environment, a measure of “attachment security.”

A quarter of the toddlers had a “poor-quality” relationship to their mothers, whereas 22 percent scored perfect at each session. At 15 years, 26 percent of the kids with relationship trouble were obese—twice as many as those without such problems.

However, the gap narrowed as more factors were taken into account, including maternal education and household income.

Today, 17 percent of all children and adolescents in the U.S. are obese, according to the Centers for Disease Control and Prevention. Even if the epidemic is fueled by poor relationships at home, there is no point in chiding mothers, Anderson said.

“Blaming parents is not likely to solve anything,” she told Reuters Health. “It’s important to recognize that there are many competing demands on parents.”

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SOURCE: Pediatrics, online December 26, 2011.