Table 7—STABLE STRONTIUM IN BONE
Age group,
months
No.
Stillbirths
0 to 3 3 to 6
6 to 9
17?
19
16
12
9 to 12
12 to 24
24 to 36
Adults
15
3
5
26
Age mean,
days
Ca, %
.
in ash
30
114
243
349
340
1020
Sr, ppm
in ash
Mg of Sr/
g of Ca
30.5
28.5
30.0
30.7
67
TT
87
85
0.23
0.25
0.29
0.24
=
+
+
+
0.02
0.02
0,04
0.02
31.9
36.0
34.7
33.0
71
110
142
117
0.31
0.32
Q.41
0.37
+
+
+
+
0.02
0,05
0.07
0.02
DISCRIMINATION BETWEEN STRONTIUM AND CALCIUM
Diet to bone discrimination factors could, in principle, be estimated from Sr or stable-strontium levels in bones and diet history.
Stable-strontium calculations are to be preferred in equal conditions
because equilibrium is ensured.
The strontium/calcium ratio in bone is related to those of diets by
the following expression, which defines a crude model:
- Strontium/calcium in bone =
CarLlukFu +ZA Ca;L;F;
Ca;+z A Ca;
where Ca = amount of calcium from placental origin
.
Ly,
strontium/calcium ratio in the total diet of the mother
F \,
fetal bone/diet of the mother
L,
{I
Ca,=calcium increment during period i
strontium/calicium ratio in the diet during period i
F,=average observed ratio of bone/diet of the child during
period i
With the data on bone and diets presented in this paper, the expression
allows calculation of the corresponding discrimination pileup for the
older age groups; but not too muchvalue should be attributed to them.
The calculations shown below are based on the *’Sr bone values
with corresponding diet history and on stable-strontium values and representative diets for the region studied.
Observed ratio
estimated from
Observed ratio
estimated from
Stillbirths
0 to 3 months
3 to 6 months
0.13
0.81
0.49
0.14
0.80
°
6 to 9 months
Age group
stable strontium
Sr
9 to 12 months
12 to 24 months
0.50
0.28
0.30
0.33
24 to 36 months
0.22
0.26
°
0.27