Figure 1Pearson's correlation between soluble transferrin receptor (sTfR) and leptin. Correlation coefficient and p value adjusted by age, sex, and waist circumference (WC) are shown.
Table 1General characteristics of the study participants.
Characteristic |
Total (n = 1350) |
Boys (n = 682) |
Girls (n = 668) |
Age (y) |
9.19 ± 1.30 |
9.24 ± 1.29 |
9.15 ± 1.30 |
Height (cm) |
135.41 ± 9.80 |
135.83 ± 8.61 |
134.98 ± 10.86 |
Weight (kg) |
33.09 ± 8.70 |
34.01 ± 8.71 |
32.15 ± 8.59* |
BMI (kg/m2) |
17.75 ± 3.00 |
18.17 ± 3.10 |
17.32 ± 2.83* |
BMI percentile (%) |
42.17 ± 30.84 |
44.08 ± 31.25 |
40.23 ± 30.31* |
Body fat (%) |
20.96 ± 7.82 |
20.32 ± 8.50 |
21.60 ± 7.03* |
WC (cm) |
61.42 ± 8.62 |
62.81 ± 8.65 |
60.01 ± 8.34* |
SBP (mmHg) |
103.66 ± 13.76 |
104.86 ± 13.36 |
102.44 ± 14.06* |
DBP (mmHg) |
68.09 ± 9.88 |
68.91 ± 9.62 |
67.25 ± 10.08* |
Total cholesterol (mg/dL) |
169.65 ± 25.92 |
167.64 ± 24.81 |
171.70 ± 26.87* |
TG (mg/dL) |
68.38 ± 39.91 |
63.40 ± 38.47 |
73.46 ± 40.73* |
HDLC (mg/dL) |
58.49 ± 11.34 |
59.74 ± 11.45 |
57.21 ± 11.09* |
Glucose (mg/dL) |
85.47 ± 7.28 |
86.20 ± 7.71 |
84.72 ± 6.75* |
Insulin (uIU/mL) |
5.25 ± 3.87 |
4.99 ± 3.64 |
5.51 ± 4.07* |
HOMA-IR |
1.13 ± 0.84 |
1.09 ± 0.80 |
1.17 ± 0.87 |
Leptin (ng/mL)a
|
5.45 ± 4.09 |
5.14 ± 4.05 |
5.78 ± 4.11 |
Hb (g/dL) |
13.37 ± 0.85 |
13.36 ± 0.88 |
13.37 ± 0.82 |
Serum ferritin (ng/mL) |
36.87 ± 19.53 |
36.68 ± 18.39 |
37.06 ± 20.64 |
sTfR (mg/L) |
2.13 ± 0.63 |
2.20 ± 0.64 |
2.06 ± 0.61* |
sTfR/log ferritin |
0.64 ± 0.27 |
0.65 ± 0.26 |
0.63 ± 0.28* |
Serum iron (μg/dL) |
98.55 ± 35.85 |
95.77 ± 36.22 |
101.38 ± 35.28* |
TIBC (μg/dL) |
336.60 ± 59.88 |
335.51 ± 61.87 |
337.71 ± 57.81 |
TS (%) |
29.52 ± 10.26 |
28.91 ± 10.57 |
30.15 ± 9.90* |
Dietary iron (mg/d)b
|
11.91 ± 3.33 |
12.01 ± 3.48 |
11.81 ± 3.17 |
Dietary vitamin C (mg/d)b
|
81.83 ± 46.10 |
82.13 ± 49.74 |
81.54 ± 42.25 |
Prevalence of MetSc
|
51/(3.78) |
21 (3.08) |
30 (4.49) |
Table 2Pearson's correlation coefficients for the association between iron status indicators and biochemical/anthropometric variables adjusted by age and sex.
|
Hba
|
Serum ferritin |
sTfR |
sTfR/log ferritin |
Serum iron |
TIBC |
TS (%) |
Height (cm) |
0.07* |
0.00 |
0.09** |
0.05 |
−0.04 |
0.04 |
−0.07* |
Weight (kg) |
0.03 |
0.07* |
0.15** |
0.06* |
−0.08* |
0.12** |
−0.15** |
BMI (kg/m2) |
0.03 |
0.09* |
0.14** |
0.06* |
−0.08* |
0.13** |
−0.15** |
BMI percentile (%) |
0.04 |
0.09* |
0.13** |
0.04 |
−0.08* |
0.14** |
−0.14** |
Body fat (%) |
0.04 |
0.15** |
0.14** |
0.03 |
−0.10** |
0.14** |
−0.16** |
WC (cm) |
0.01 |
0.07* |
0.21** |
0.11** |
−0.13** |
0.08* |
−0.17** |
SBP (mmHg) |
−0.07* |
0.03 |
0.12** |
0.07* |
−0.06* |
0.03 |
−0.08** |
DBP (mmHg) |
−0.02 |
0.04 |
0.04 |
0.01 |
−0.04 |
0.03 |
−0.07* |
Total cholesterol (mg/dL) |
0.06* |
0.06* |
0.07* |
0.04 |
0.06* |
0.07* |
0.02 |
TG (mg/dL) |
0.06* |
0.03 |
0.07* |
0.01 |
−0.03 |
0.12** |
−0.09* |
HDLC (mg/dL) |
0.07* |
−0.10* |
−0.04 |
0.02 |
0.11** |
0.02 |
0.09** |
Glucose (mg/dL) |
−0.02 |
−0.04 |
0.03 |
0.03 |
−0.09* |
0.04 |
−0.12** |
Insulin (uIU/mL)b
|
0.06 |
0.03 |
−0.02 |
−0.04 |
−0.09* |
0.10** |
−0.14** |
HOMA-IRb
|
0.06* |
0.03 |
−0.02 |
−0.03 |
−0.10** |
0.11** |
−0.15** |
Leptinc
|
0.09 |
0.03 |
0.18** |
0.10* |
−0.18** |
0.20** |
−0.25** |
Table 3Iron status indicators for the study participants grouped according to the homeostasis model assessment insulin resistance (HOMA-IR) tertile (HT).
|
HT1
|
HT2
|
HT3
|
p
|
(0.14–0.7) |
(0.71–1.14) |
(1.15–7.48) |
HOMA-IR level |
0.50 ± 0.14c
|
0.92 ± 0.1b
|
1.98 ± 0.96a
|
<0.0001 |
Hb |
13.30 ± 0.81 |
13.43 ± 0.78 |
13.45 ± 0.88 |
0.0648 |
Serum ferritin (ng/mL) |
34.94 ± 18.35 |
35.87 ± 19.58 |
38.04 ± 19.17 |
0.7579 |
sTfR (mg/L) |
2.13 ± 0.61 |
2.16 ± 0.61 |
2.12 ± 0.64 |
0.0818 |
sTfR/log ferritin |
0.65 ± 0.27 |
0.66 ± 0.30 |
0.63 ± 0.26 |
0.1874 |
Serum iron (μg/dL) |
103.33 ± 35.84a
|
96.48 ± 36.27b
|
95.29 ± 34.44b
|
0.0341 |
TIBC (μg/dL) |
324.77 ± 55.97c
|
336.48 ± 60.14b
|
344.77 ± 60.63a
|
0.0005 |
TS (%) |
32.00 ± 10.13a
|
28.80 ± 10.20b
|
27.79 ± 9.67c
|
<0.0001 |
Table 4Iron status indicators of children by metabolic syndrome status (MetS).
Characteristic |
No MetSa (n = 1299) |
MetS (n = 51) |
p
|
Hb (g/dL) |
13.37 ± 0.84 |
13.35 ± 1.02 |
0.7629 |
Serum ferritin (ng/mL) |
36.67 ± 19.58 |
41.94 ± 17.82 |
0.1544 |
sTfR (mg/L) |
2.13 ± 0.64 |
2.34 ± 0.79 |
0.0077 |
sTfR/log ferritin |
0.64 ± 0.27 |
0.65 ± 0.24 |
0.4872 |
Serum iron (μg/dL) |
98.89 ± 35.63 |
89.88 ± 40.58 |
0.0464 |
TIBC (μg/dL) |
336.41 ± 59.62 |
341.49 ± 66.70 |
0.8301 |
TS (%) |
29.64 ± 10.20 |
26.40 ± 11.21 |
0.0238 |