Table 5:
Optimal BMI percentile cut-offs, as determined using the Youden index, for the CDC and WHO growth curves to predict cardiometabolic risk
| Risk factor | Area under the curve | |||||
|---|---|---|---|---|---|---|
|
| ||||||
| 9 -year-olds n = 779 |
13-year-olds n = 816 |
16-year-olds n = 871 |
||||
|
|
|
|
||||
| CDC | WHO | CDC | WHO | CDC | WHO | |
| Total cholesterol ≥ 4.4 mmol/L | ||||||
|
| ||||||
| Boys | 55.97 | 56.32 | 87.83 | 90.90 | 72.88 | 75.14 |
|
| ||||||
| Girls | 65.09 | 68.86 | 35.60 | 34.16 | 39.92 | 36.41 |
|
| ||||||
| HDL cholesterol < 1.0 mmol/L | ||||||
|
| ||||||
| Boys | 61.30 | 64.69 | 42.96 | 45.60 | 78.66 | 80.91 |
|
| ||||||
| Girls | 64.95 | 69.28 | 84.52 | 87.13 | 67.36 | 64.62 |
|
| ||||||
| LDL cholesterol ≥ 2.6 mmol/L | ||||||
|
| ||||||
| Boys | 53.18 | 56.32 | 87.83 | 90.90 | 72.61 | 74.95 |
|
| ||||||
| Girls | 68.60 | 73.46 | 37.51 | 34.16 | 72.70 | 71.72 |
|
| ||||||
| Triglycerides ≥ 1.7 mmol/L | ||||||
|
| ||||||
| Boys | 87.17 | 91.76 | 90.84 | 94.80 | 76.07 | 78.15 |
|
| ||||||
| Girls | 85.65 | 89.55 | 60.90 | 58.47 | 81.12 | 82.64 |
|
| ||||||
| Systolic blood pressure* | n = 772 | n = 811 | n = 870 | |||
|
| ||||||
| Boys | 48.51 | 34.68 | 67.21 | 71.54 | 86.17 | 88.63 |
|
| ||||||
| Girls | 84.37 | 88.46 | 74.69 | 71.62 | 74.90 | 76.00 |
|
| ||||||
| Diastolic blood pressure*† | ||||||
|
| ||||||
| Boys | 96.01 | 99.0 | — | — | 35.67 | 36.21 |
|
| ||||||
| Girls | — | — | 75.12 | 76.15 | 92.61 | 95.54 |
|
| ||||||
| Insulin‡ | n = 706 | n = 723 | n = 812 | |||
|
| ||||||
| Boys | 83.41 | 88.16 | 84.91 | 88.36 | 80.96 | 83.58 |
|
| ||||||
| Girls | 50.96 | 54.48 | 64.37 | 65.14 | 57.98 | 55.27 |
|
| ||||||
| Glucose ≥ 5.6 mmol/L | n = 779 | n = 816 | n = 871 | |||
|
| ||||||
| Boys | 87.43 | 91.96 | 65.43 | 68.27 | 27.05 | 27.31 |
|
| ||||||
| Girls | 46.31 | 50.07 | 69.13 | 68.38 | 75.91 | 74.52 |
|
| ||||||
| Cardiometabolic abnormalities§ | ||||||
|
| ||||||
| 1 | ||||||
|
| ||||||
| Boys | 55.56 | 54.19 | 37.93 | 39.15 | 75.69 | 77.74 |
|
| ||||||
| Girls | 65.09 | 69.35 | 66.34 | 69.09 | 75.73 | 75.77 |
|
| ||||||
| 2 | ||||||
|
| ||||||
| Boys | 54.38 | 64.39 | 62.76 | 67.59 | 72.61 | 74.95 |
|
| ||||||
| Girls | 53.80 | 57.16 | 62.38 | 60.26 | 68.31 | 66.49 |
|
| ||||||
| ≥ 3 | ||||||
|
| ||||||
| Boys | 87.17 | 91.85 | 87.83 | 90.90 | 79.75 | 82.05 |
|
| ||||||
| Girls | 85.21 | 89.24 | 71.56 | 68.42 | 72.74 | 71.72 |
Note: BMI = body mass index, CDC = Centers for Disease Control and Prevention, HDL = high-density lipoprotein, LDL = low-density lipoprotein, WHO = World Health Organization.
*
≥ 90th percentile for age, height and sex as defined by the National High Blood Pressure Education Program.
†
There were too few cases of unfavourable diastolic blood pressure (≥ 90th percentile) for 9-year-old girls and 13-year-old boys to calculate optimal BMI percentile cut-offs.
‡
Insulin ≥ 38 pmol/L (9-year-olds) or ≥ 60 pmol/L (13- and 16- year-olds).
§
Versus no abnormalities. Missing values were assumed to be normal.