Table 5.
Mean FFMI z-score of adolescents in the different groups classified by BMI percentiles in comparison with the groups that had matching group assignment based on BMI percentiles as well as FMI (“same classification”) and in the groups whose FMI was classified “below” or “above” the BMI percentile range
| Mean FFMI z-scorea | |||||
|---|---|---|---|---|---|
| Classified below | p-valueb | Same classification | p-valuec | Classified above | |
| BMI < 75th percentile | − 0.34 (0.03) | 0.170 | − 0.44 (0.11) | ||
| BMI 75th– < 85th percentile | 1.17 (0.05) | < 0.001 | 0.51 (0.05) | < 0.001 | 0.06 (0.07) |
| BMI 85th– < 90th percentile | 1.30 (0.06) | < 0.001 | 0.81 (0.09) | < 0.001 | 0.15 (0.10) |
| BMI 90th– < 95th percentile | 1.55 (0.08) | < 0.001 | 1.02 (0.09) | < 0.001 | 0.35 (0.09) |
| BMI 95th– < 97th percentile | 1.85 (0.08) | < 0.001 | 1.32 (0.11) | 0.010 | 0.93 (0.10) |
| BMI ≥ 97th percentile | 2.00 (0.36) | 0.322 | 1.86 (0.10) | ||
All categories were compared using ANCOVA, adjusted for sex and age, and bias corrected and accelerated
BMI body mass index, FFMI fat-free mass index
aMean (SE), adjusted for sex and age
bp-value for the comparison of lower and same FMI classification
cp-value for the comparison of the same and higher FMI classification