Children: ages 5 to 18 years (446 male, 1125 female)
Measurements:
(1) anthropometric examination
(2) whole body DXA scan (for bone area, lean tissue mass, fat and percent body fat, bone mineral content and bone mineral density).
Parameters with point assignments:
(1) sex
(2) race
|
Parameter
|
Finding
|
Points
|
|
sex
|
female
|
0
|
|
|
male
|
1
|
|
race
|
Black
|
-1
|
|
|
Hispanic
|
1
|
|
|
White
|
0
|
The first method based on the physical examination:
A =
= ((body height in cm) ^ 2.31) * 0.001 * ((1.75 * (points for sex)) + 6.98)
B =
= (16.4 * (weight in kilograms)) + (37.7 * (age in years)) – (77.3 * (points for sex)) – (45.8 * (points for race)) - 503
bone mineral content in grams by Method 1 =
= A + B
If DEXA scanning data is also available, a second method can be used:
C =
= LN(bone area in square cm) * (1.37 – (0.068 * (points for sex)))
D =
= (0.002 * (lean tissue mass in kg)) – (0.003 * (percent body fat)) + (0.47 * (points for sex) – 2.81
LN (bone mineral content in grams) =
= C + D
bone mineral content in grams by Method 2 =
= EXP(C + D)
where:
• Percent body fat is a number between 0 and 100.
• I am not sure what normal values for the bone area can be expected.
Performance measures:
• r^2 for Method 1 is 0.936, with SEE 160 grams
• r^2 for Method 2 is 0.98 and SEE = 0.067
Limitations:
• The equations may not be accurate for children with diseases that may affect normal bone growth (AIDS, cystic fibrosis, liver failure, cancer, growth hormone deficiency, etc.)
