HealthDay News — A sibling may be a better predictor of a pediatric patient’s obesity status than his or her parents, especially for same-gender siblings, according to a study published in the American Journal of Preventive Medicine.

“Despite prior research on this subject, little effort has been made to integrate parent and sibling studies to compare a child’s obesity status with that of a sibling and parent,” wrote Mark C. Pachucki, PhD, of Massachusetts General Hospital in Boston, and colleagues.

After surveying 1,948 adult patients who had one or two children, the inspectors analyzed patients’ sociodemographic information, height and weight for adult and child, and information about physical activity and food environment.

Continue Reading

In single-child households, it was 2.2 times more likely that the child would be obese if a parent was obese, reported the investigators. In two-child households, having an obese younger sibling was more strongly associated with elder-child obesity (odds ratio, 5.4) than a parent’s obesity status (OR, 2.3).

Parent obesity status was no longer significant when an obese elder sibling was present and associated with younger-child obesity (OR, 5.6). Patterns between siblings of the same gender were stronger than between different genders, when examining within-family sibling obesity. Child physical activity was significantly associated with obesity status.

“The finding that a sibling may be a better predictor of a child’s obesity than his or her parents (especially for same-gender siblings) contributes to a growing body of work regarding the influence of siblings on a variety of children’s health behaviors, including smoking, antisocial behavior, and substance use,” noted the researchers.


  1. Pachucki M et al. American Journal of Preventive Medicine. 2014; doi: