Table 4.
BMIz Change Across 3 Time Periods Stratified by Initial Weight Status†
| Normal Weight | |||||
|---|---|---|---|---|---|
| Characteristic | Obese | Overweight | Underweight | 10th to 85th Percentile | 5th to 95th percentile |
| No. of unique participants | 259 | 255 | 117 | 907 | 1173 |
| No. of observations | 606 | 566 | 278 | 2120 | 2774 |
| BMIz at enrollment (Intercept) | 2.12 (1.87 to 2.36) | 1.35 (1.16 to 1.54) | −2.04 (−2.47 to −1.60) | 0.19 (0.07 to 0.31) | 0.39 (0.27 to 0.51) |
| Annual rate of BMIz change | |||||
| First academic year | −0.74 (−1.14 to −0.34)* | −0.22 (−0.53 to 0.08) | 1.84 (1.20 to 2.49)* | 0.12 (−0.07 to 0.31) | 0.09 (−0.09 to 0.27) |
| Summer | 0.44 (−0.83 to 1.70) | 0.24 (−0.71 to 1.18) | −1.39 (−3.37 to −0.59)* | 0.65 (0.07 to 1.24)* | 0.53 (−.0.04 to 1.10) |
| Second academic year | 0.19 (−1.26 to 1.64) | −0.44 (−1.53 to 0.65) | −0.15 (−2.40 to 2.08) | −1.12 (−1.82 to −0.43)* | −1.03 (−1.70 to −0.36)* |
| Male (vs female) | 0.34 (0.18 to 0.49)* | 0.13 (0.01 to 0.25)* | 0.24 (−0.02 to 0.49) | −0.01 (−0.08 to 0.06) | −0.04 (−0.11 to 0.03) |
| Nonwhite (vs white) race/ethnicity | 0.13 (−0.02 to 0.29) | 0.07 (−0.05 to 0.19) | 0.34 (0.07 to 0.62)* | −0.04 (−0.11 to 0.04) | −0.002 (−0.74 to 0.74) |
| Two parent (vs single) | 0.05 (−0.11 to 0.21) | −0.13 (−0.25 to −0.01)* | −0.14 (−0.40 to 0.12) | −0.12 (−0.20 to −0.05)* | −0.12 (−0.19 to −0.05)* |
*
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) stratified by initial weight status.