Background
Methods
Study population
Sampling and data collection
Clinical assessment
Laboratory analyses
Dietary assessment
Questionnaires
Statistical analysis
Results
Study population
Iron status and anemia
Age, y | Anemia2
| Depleted iron stores | Elevated iron stores | Iron deficiency anemia | Iron deficient erthrypoiesis3
| Iron intake < EAR4
| ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
n
|
%(95% CI) |
n
|
%(95% CI) |
n
|
%(95% CI) |
n
|
%(95% CI) |
n
|
%(95% CI) |
n
|
%
| |
18-30 | 169 | 17.9 | 333 | 40.3 | 333 | - | 166 | 11.7 | 153 | 1.0 | 312 | 15.7 |
(12.7-24.6) | (34.3-46.6) | (7.4-18.2) | (0.1-6.9) | |||||||||
31-50 | 326 | 21.3 | 583 | 37.0 | 583 | 0.9 | 316 | 15.4 | 294 | 6.2 | 583 | 17.3 |
(16.7-26.8) | (32.7-41.6) | (0.3-3.0) | (11.5-20.3) | (3.3-11.4) | ||||||||
≥51 | 202 | 24.9 | 344 | 9.2 | 344 | 5.9 | 182 | 3.9 | 186 | 0.7 | 326 | 0.6 |
(18.1-33.3) | (6.3-13.2) | (3.4-10.1) | (1.5-9.6) | (0.2-3.0) | ||||||||
Total | 697 | 21.7 | 1260 | 29.4 | 1260 | 2.2 | 664 | 11.1 | 633 | 3.3 | - | - |
(18.3-25.5) | (26.7-32.3) | (1.3-3.6) | (8.7-14.0) | (1.9-5.8) |
Dietary intake on the previous day, unit
|
n
| Multivariate | P-value | |
---|---|---|---|---|
Coefficient3
| ||||
Energy, MJ
| 1123 | 7.56 (5.43-10.4) | ||
Traditional food,% energy
| 1123 | 6.8 (0-24) | 0.001 | 0.008 |
Traditional food meat, g
| 1123 | 81.6 (0-277) | ||
All meat, g
| 1123 | 235 (128-420) | ||
Dietary iron, mg
| 1123 | 12.8 (8.2-20.3) | ||
Dietary iron from traditional food, mg
| 1123 | 1.1 (0-9.0) | ||
Dietary iron from non-traditional meats, mg
| 1123 | 0.5 (0-2.0) | ||
Heme iron, mg
| 1123 | 4.0 (1.2-10.6) | ||
Vitamin C, mg
| 1123 | 59.0 (15.5-162.7) | ||
Calcium, mg
| 1123 | 388 (238-610) | ||
Vitamin A, μg RAE
| 1123 | 353 (161-684) | ||
Tea, mL
| 1123 | 0 (0-500) | ||
Daily frequency of consumption, n/d
| ||||
Sea mammals | 1105 | 0.08 (0.01-0.31) | 0.117 | <0.001 |
Game | 1105 | 0.27 (0.07-0.77) | -0.034 | 0.095 |
Fish | 1105 | 0.11 (0.02-0.29) | -0.014 | 0.735 |
Liver, all species
| 1105 | 0 (0-0.02) | 0.303 | 0.022 |
Iron status and other indicators | ||||
RBC LC-PUFA (% of total fatty acids) | 1197 | 3.67 (1.91-5.76) | 0.038 | <0.001 |
Serum hs-C-reactive protein (mg/L) | 1210 | 1.3 (0.4-3.4) | 0.031 | <0.001 |
Hemoglobin (g/L) | 1149 | 128 (119-136) | 0.009 | <0.001 |
Serum soluble transferrin receptor (mg/L) | 575 | 1.33 (1.12-1.63) | -0.287 | <0.001 |
Serum ferritin (μg/L) | 1210 | 24.5 (14.0-51.0) | - | - |
H. pylori positive | 1268 | 71.9 (69.4-74.3)2
| -0.047 | 0.044 |
Correlates of iron status
Multivariate odds ratio3
| 95% Confidence interval for OR | P-value | |
---|---|---|---|
Postmenopausal (1 = yes, 0 = no) | 0.120 | 0.069 – 0.207 | <0.001 |
% Body fat > cut-off(1 = yes, 0 = no) | 0.414 | 0.297 – 0.578 | <0.001 |
hs-CRP2 (1 = 3-10 mg/L, 0 = <3 mg/L) | 0.571 | 0.369 – 0.884 | 0.012 |
RBC LC-PUFA,% of total fatty acids
| 0.896 | 0.793 – 1.012 | 0.068 |
Oral contraceptive use (1 = yes, 0 = no) | 0.426 | 0.262 – 0.693 | 0.078 |
Food insecure (1 = yes, 0 = no) | 1.37 | 0.98 – 1.92 | 0.001 |
Food insecure* RBC LC-PUFA | 0.842 | 0.721 – 0.984 | 0.030 |
Discussion
Full model1
| Coefficient | 95% Confidence Interval | P-value |
---|---|---|---|
% Body fat > cut-off(1 = yes, 0 = no) | -0.186 | -0.475-0.103 | 0.208 |
Predicted mean (0)
|
4.05
|
3.83-4.27
|
<0.001
|
Predicted mean (1)
|
3.86
|
3.68-4.04
|
<0.001
|
Smoking status (1 = yes, 0 = no) | -0.337 | -0.664 – 0.011 | 0.043 |
Predicted mean (0)
|
4.18
|
3.91-4.45
|
<0.001
|
Predicted mean (1)
|
3.84
|
3.68-4.01
|
<0.001
|
hs-CRP (1 = ≥10 mg/L, 0 = <10 mg/L) | -0.213 | -0.751-0.325 | 0.437 |
Predicted mean (0)
|
3.96
|
3.81-4.10
|
<0.001
|
Predicted mean (1)
|
3.74
|
3.22-4.26
|
<0.001
|
Age (years) | 0.086 | 0.076-0.096 | <0.001 |
Subset analysis of traditional communities
2
| |||
% Body fat > cut-off(1 = yes, 0 = no) | 0.246 | -0.049-0.541 | 0.103 |
Predicted mean (0)
|
4.37
|
4.16-4.57
|
<0.001
|
Predicted mean (1)
|
4.55
|
4.37-4.74
|
<0.001
|
Smoking status (1 = yes, 0 = no) | -0.498 | -0.828—0.168 | 0.003 |
Predicted mean (0)
|
4.81
|
4.53-5.09
|
<0.001
|
Predicted mean (1)
|
4.31
|
4.15-4.47
|
<0.001
|
hs-CRP (1 = ≥10 mg/L, 0 = <10 mg/L) | -0.307 | -0.650-0.036 | 0.080 |
Predicted mean (0)
|
4.52
|
4.36-4.67
|
<0.001
|
Predicted mean (1)
|
4.21
|
3.91-4.51
|
<0.001
|
Age (years) | 0.103 | 0.094-0.113 | <0.001 |