Researchers at the University of Bristolin Great Britain have devised a newmeasure to determine at infancy the likelihoodof obesity. The "ponderal index"divides an infant's weight in kilograms byits length in centimeters cubed. Althoughit is similar to the body mass index,which is weight in kilograms divided byheight in meters squared, the ponderalindex is believed to offer a gauge that isrelative to body composition. Researchersused dual-energy x-ray absorptiometryto measure lean body mass and percentageof body fat in more than 6000children between 9 and 10 years old. Aspredicted, fat mass and lean massincreased with birth weight, but therewas no connection between birth weightand the ratio of fat to lean mass.Researchers did, however, find that thehigher a child's ponderal index was atbirth, the greater was the ratio of fat tolean mass at ages 9 to 10. They alsodetermined thata higher ponderal index score meanta higher percentage of body fat.Researchers found that childrenwho were longer at birth had lower percentages ofbody fat at ages 9 to 10. The study can befound in the October 2006 issue of theAmerican Journal of Clinical Nutrition.
Ms. Farley is a freelance medicalwriter based in Wakefield, RI.