Internal, external cue responses tied to obesity.

BALTIMORE -- Children with greater body mass indexes appear to be more responsive to external food cues and less responsive to internal satiety signals, according to a study involving almost 11,000 children.

The findings, which were presented at the annual meeting of the American Psychosomatic Society, suggest that variation in responsiveness to internal and external cues could contribute to variation in adiposity, said Jane Wardle, Ph.D., who is the director of the Health Behaviour Research Centre at University College London.

It's long been speculated that obese individuals have an overresponsive meal-initiation system (high food responsiveness) and/or inability to end a meal (low satiety sensitivity).

For this study, the researchers looked at two samples: a preschool group of 572 children (aged 3-5 years) and an older group of 10,364 twins (aged 8-11 years). The twins are part of the larger Twins Early Development Study (TEDS), which involves more than 16,000 families whose twins were born between 1994 and 1996.

Eating behavior of the twins and preschoolers was assessed when the children were between 8 and 11 years of age using parent reporting on the Child Eating Behaviour Questionnaire. The researchers were particularly interested in satiety sensitivity (as measured by the satiety responsiveness scale) and food responsiveness (as measured by the enjoyment of food subscale). The researchers determined the height and weight of the preschool group, while the parents measured the height, weight, and waist circumference of the twin group.

Satiety responsiveness was negatively correlated with BMI (adjusted for age and sex) in both groups and also was negatively correlated with waist circumference in the twin group.

So children with greater BMIs responded poorly to satiety signals. Food responsiveness was positively correlated with BMI (adjusted for age and sex) in both groups and with waist circumference in the twin group.

In terms of satiety responsiveness and food responsiveness, "it's not just a difference between the obese and everybody else. It's a quantitative variation across the distribution," Dr. Wardle said. The data provide evidence that "there are eating behavior traits that have long been implicated in obesity that show a gradient association with weight." BY KERRI WACHTER Senior Writer