School programs and characteristics and their influence on student BMI: findings from healthy passages.
BACKGROUND
Little is known about the contribution of school contextual factors to individual student body mass index (BMI). We set out to determine if school characteristics/resources: (1) are associated with student BMI; (2) explain racial/ethnic disparities in student BMI; and (3) explain school-level differences in student BMI.


METHODS
Using gender-stratified multi-level modeling strategies we examined the association of school characteristics/resources and individual BMI in 4,387 5(th) graders in the Healthy Passages Longitudinal Study of Adolescent Health. Additionally, we examined the association of race/ethnicity and individual BMI as well as the between-school variance in BMI before and after adding individual and school characteristics to test for attenuation.


RESULTS
The school-level median household income, but not physical activity or nutrition resources, was inversely associated with female BMI (β = -0.12, CI: -0.21,-0.02). Neither school demographics nor physical activity/nutrition resources were predictive of individual BMI in males. In Black females, school characteristics attenuated the association of race/ethnicity and BMI. Individual student characteristics-not school characteristics/resources-reduced the between-school variation in BMI in males by nearly one-third and eliminated it in females.


CONCLUSIONS
In this cohort of 5(th) graders, school SES was inversely associated with female BMI while school characteristics and resources largely explained Black/White disparities in female weight status. Between-school differences in average student weight status were largely explained by the composition of the student body not by school characteristics or programming.
Division of Adolescent Medicine, Boston Children's Hospital, Boston, Massachusetts, United States of America.
Tracy K
TK
Richmond
Statistics, RAND Corporation, Santa Monica, California, United States of America.
Marc N
MN
Elliott
Division of Management, Policy, and Community Health, The University of Texas School of Public Health/Blue Cross and Blue Shield of Texas Research Program in Payment Systems and Policies, Houston, Texas, United States of America.
Luisa
L
Franzini
Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, Massachusetts, United States of America.
Ichiro
I
Kawachi
University of Texas School of Public Health, Dallas, Texas, United States of America.
Margaret O
MO
Caughy
Birmingham, Alabama, United States of America.
M Janice
MJ
Gilliland
Epidemiology, Decision Resources, Burlington, Massachusetts, United States of America.
Courtney E
CE
Walls
Department of Maternal and Child Health, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
Frank A
FA
Franklin
Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Richard
R
Lowry
Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Stephen W
SW
Banspach
Department of Medicine, Boston Children's Hospital, Boston, Massachusetts, United States of America.
Mark A
MA
Schuster
D000293:Adolescent; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D006262:Health; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D044469:Racial Groups; D012574:Schools; D013334:Students; D014481:United States