title: Tracking relative weight in subjects studied longitudinally from ages 3 to 13 years.
abstract: Heights and weights of a large sample of subjects studied longitudinally from ages 3 and 13 years were used to calculate relative weight, using a Body Mass Index score (BMI) which estimates adiposity. Males and females differed significantly in BMI scores only at ages 3 and 13 years. The correlations between BMI scores at all ages were positive and significant. The subjects were divided at each age into a 'light', an 'average' and a 'heavy' group based on the position of their BMI score relative to the 25th and 75th percentiles. Subjects were 'tracked' from ages 3, 7 and 11 years to determine whether they had remained in the same BMI group by age 13 years relative to their peers. Slightly fewer than half of the 3 year old subjects but the majority of 7 and 11 year old subjects remained in the same relative weight group by age 13 years. Only 1% of 7 and 11 year old subjects in the top and the bottom quartiles for BMI scores shifted from one extreme group to the other. Relative weight at 3, 7 and 11 years was more persistent for subjects with extreme bodyweights than subjects with bodyweights in the middle range. Consistent with the pattern of correlations, the tracking pattern for all 3 groups showed that subjects' BMI scores remained more stable as the subjects grew older.
authors.affiliation: Harvard University, Cambridge, Massachusetts.
authors.forename: J L
authors.initials: JL
authors.lastname: Kelly
authors.forename: W R
authors.initials: WR
authors.lastname: Stanton
authors.forename: R
authors.initials: R
authors.lastname: McGee
authors.forename: P A
authors.initials: PA
authors.lastname: Silva
mesh_terms: D000293:Adolescent; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D012737:Sex Factors