The identification of children with adverse risk factor levels by body mass index cutoffs from 2 classification systems: the Bogalusa Heart Study.
BACKGROUND
The cutoffs from the Centers for Disease Control and Prevention (CDC) growth charts and from the Cooper Institute (FitnessGram) are widely used to identify children who have a high body mass index (BMI).


OBJECTIVE
We compared the abilities of these 2 systems to identify children who have adverse lipid concentrations and blood pressure measurements and the reliability (consistency) of each classification system over time (mean follow-up: 7 y).


METHODS
A cross-sectional analysis based on data from 22,896 examinations of 5- to 17-y-olds was conducted. Principal components analyses were used to summarize levels of the 5 risk factors, and likelihood ratios and the κ statistic were used to compare the screening abilities of the 2 systems. Of these children, 3972 were included in longitudinal analyses.


RESULTS
There were marked differences in the prevalence of a high FitnessGram BMI by age, with the prevalence among boys increasing from 2.5% to 21% between the ages of 5 and 11 y. The identification of adverse risk factors by the 2 systems was only fair (κ = 0.25), but there was little difference in the abilities of the CDC and FitnessGram cutoffs to identify high-risk children. Longitudinal analyses, however, indicated that the agreement between initial and follow-up FitnessGram classifications was substantially lower than that based on CDC cutoffs (κ = 0.28 compared with 0.49).


CONCLUSIONS
The FitnessGram and CDC cutoffs have similar abilities to identify high-risk children. However, a high FitnessGram BMI is difficult to interpret because the reliability over time is low, and the prevalence increases markedly with age.
Freedman
David S
DS
Division of Nutrition, Physical Activity and Obesity, Centers for Disease Control and Prevention, Atlanta, GA, USA. dxf1@cdc.gov
Fulton
Janet E
JE
Dietz
William H
WH
Pan
Liping
L
Nihiser
Allison J
AJ
Srinivasan
Sathanur R
SR
Berenson
Gerald S
GS
D000293:Adolescent; D000367:Age Factors; D001794:Blood Pressure; D001823:Body Composition; D015992:Body Mass Index; D002487:Centers for Disease Control and Prevention, U.S.; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D057238:Growth Charts; D006801:Humans; D008055:Lipids / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D008403:Mass Screening / Q000379:methods*; D009765:Obesity / Q000175:diagnosis* / Q000453:epidemiology; D015995:Prevalence; D012016:Reference Values; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
D008055:Lipids