Table 3.

BMIz Change Across 3 Time Periods Stratified by Race/Ethnicity and Gender^†

		Boys		Girls
Characteristic	Full sample	White	Minority	White	Minority
No. of unique participants	1914	637	347	562	374
No. of observations	4374	1446	816	1199	913
BMIz at enrollment (Intercept)	0.52 (0.39 to 0.65)	0.67 (0.46 to 0.89)	0.63 (0.35 to 0.92)	0.53 (0.30 to 0.75)	0.77 (0.56 to 0.98)
Annual rate of BMIz change
First academic year	−0.07 (−0.28 to 0.14)	0.11 (−0.27 to 0.49)	−0.10 (−0.63 to 0.43)	−0.04 (−0.42 to 0.34)	−0.38 (−0.77 to 0.02)
Summer	0.62 (−0.00 to 1.23)	0.10 (−1.04 to 1.23)	1.52 (−0.57 to 2.46)	0.12 (−1.03 to 1.27)	1.69 (0.53 to 2.86)*
Second academic year	−0.82 (−1.50 to −0.13)*	−0.46 (−1.72 to 0.79)	−1.37 (−3.01 to 0.27)	−0.34 (−1.66 to 0.98)	−1.36 (−2.65 to −0.08)*
Male (vs female)	0.12 (0.05 to 0.20)*
Nonwhite (vs white) race/ethnicity	0.16 (0.08 to 0.24)*
Two parent (vs single)	−0.09 (−0.17 to −0.02)*	−0.27 (−0.41 to −0.14)*	0.16 (−0.04 to 0.36)	−0.18 (−0.32 to −0.04)*	0.19 (0.03 to 0.35)*

^*P <.05.

^†Multivariate models showing slope and 95% confidence intervals for body mass index z score (BMIz) (standard deviation unit) change across each of 3 time periods (first academic year, summer, and second academic year) in full sample and stratified by race/ethnicity and gender.