Stability of adolescent body mass index during three years of follow-up.
OBJECTIVE
A 4-year longitudinal study was conducted to determine the prevalence of overweight, detect shifts in body mass index (BMI) distribution, and determine which adolescents were at risk for pathologic weight gain.


METHODS
BMI was analyzed in 1746 adolescents in years 1 (2001-2002) through 4 (2004-2005) of a school-based study. Changes in BMI-Z according to baseline BMI category were examined with general linear modeling.


RESULTS
In year 1, the prevalence of at risk for overweight (BMI = 85th-95th percentile) and overweight (BMI > or = 95th percentile) was 19.1% and 18.1%, respectively. Between years 1 and 4, the cohort exhibited no increase in the prevalence of at risk for overweight (19.1% versus 17.2%) or overweight (18.2% versus 18.8%; P > .5). The mean BMI Z-score (BMI-Z) for the cohort was identical in years 1 and 4 (0.66 +/- 1.0 Z-score units). Although the overall cohort exhibited stability in BMI-Z, individuals at the lowest categories of BMI-Z (year 1 BMI Z-score < 0) exhibited significant increases in BMI Z-score by year 4 (P < .01), with lean girls gaining more than lean boys (P for difference < .007).


CONCLUSIONS
The study cohort exhibited stability in adiposity during 3 years of follow-up. However, lean adolescents, particularly girls, experienced significant increases in BMI-Z, beyond that expected for age- and sex-related growth.
Crimmins
Nancy A
NA
Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA. nancy.crimmins@cchmc.org
Dolan
Lawrence M
LM
Martin
Lisa J
LJ
Bean
Judy A
JA
Daniels
Stephen R
SR
Lawson
M Louise
ML
Goodman
Elizabeth
E
Woo
Jessica G
JG
D050154:Adiposity; D000293:Adolescent; D000704:Analysis of Variance; D015992:Body Mass Index; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016018:Least-Squares Analysis; D016014:Linear Models; D008297:Male; D009765:Obesity / Q000453:epidemiology* / Q000517:prevention & control; D009820:Ohio / Q000453:epidemiology; D050177:Overweight; D015995:Prevalence; D012306:Risk; D015430:Weight Gain