Table 2. Adjusted BMI z Scores Among Students With a Baseline BMI in the 85th Percentile or Higher (n = 6534), by Groupa.
| Variable | Mean (SE) z score | z Score 1-y change (95% CI) | z Score 2-y change (95% CI) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Baseline | 1 y | 2 y | Within-group | Between-groupb | P valuec | Within-group | Between-groupb | P valuec | |
| All students | |||||||||
| BMI reporting | 1.74 (0.01) | 1.69 (0.01) | 1.69 (0.02) | −0.05 (−0.08 to −0.02) | −0.003 (−0.02 to 0.01) | .71 | −0.05 (−0.11 to 0.00) | 0.01 (−0.02 to 0.03) | .62 |
| BMI screening | 1.75 (0.01) | 1.70 (0.01) | 1.69 (0.02) | −0.05 (−0.07 to −0.02) | NA | NA | −0.06 (−0.12 to −0.00) | NA | NA |
| Hispanic students | |||||||||
| BMI reporting | 1.77 (0.01) | 1.73 (0.01) | 1.73 (0.02) | −0.04 (−0.07 to −0.01) | 0.003 (−0.01 to 0.02) | .70 | −0.04 (−0.09 to 0.02) | 0.02 (−0.00 to 0.05) | .07 |
| BMI screening | 1.78 (0.01) | 1.73 (0.01) | 1.72 (0.02) | −0.05 (−0.07 to −0.02) | NA | NA | −0.06 (−0.12 to −0.00) | NA | NA |
| Non-Hispanic students | |||||||||
| BMI reporting | 1.67 (0.02) | 1.61 (0.02) | 1.58 (0.02) | −0.06 (−0.09 to −0.03) | −0.01 (−0.04 to 0.01) | .25 | −0.09 (−0.15 to −0.03) | −0.03 (−0.07 to 0.01) | .12 |
| BMI screening | 1.69 (0.02) | 1.64 (0.02) | 1.62 (0.03) | −0.05 (−0.08 to −0.01) | NA | NA | −0.06 (−0.12 to −0.00) | NA | NA |
| Elementary school studentsd | |||||||||
| BMI reporting | 1.76 (0.01) | 1.71 (0.01) | 1.69 (0.02) | −0.05 (−0.08 to −0.03) | −0.01 (−0.03 to 0.01) | .32 | −0.07 (−0.12 to −0.02) | −0.01 (−0.03 to 0.02) | .70 |
| BMI screening | 1.77 (0.01) | 1.72 (0.01) | 1.70 (0.02) | −0.05 (−0.07 to −0.02) | NA | NA | −0.07 (−0.12 to −0.02) | NA | NA |
| Non–elementary school students | |||||||||
| BMI reporting | 1.73 (0.02) | 1.66 (0.02) | 1.61 (0.03) | −0.08 (−0.11 to −0.06) | 0.01 (−0.01 to 0.03) | .43 | −0.12 (−0.18 to −0.07) | 0.02 (−0.02 to 0.06) | .24 |
| BMI screening | 1.74 (0.02) | 1.65 (0.02) | 1.60 (0.02) | −0.09 (−0.12 to −0.06) | NA | NA | −0.15 (−0.20 to −0.09) | NA | NA |
Abbreviations: BMI, body mass index; NA, not applicable.
a
Analyses adjusted for sex, race/ethnicity (except for models stratified by Hispanic students), grade (except for models stratified by grade level), school district, school-level percentage of students eligible for free and reduced-price meal, and calendar year.
b
Between-group difference: BMI reporting group minus BMI screening group.
c
P value for between-group difference.
d
Elementary: in grades 3 to 5 at baseline.