Skip to main content
. 2023 Dec 3;154(2):658–669. doi: 10.1016/j.tjnut.2023.12.001

TABLE 1.

Descriptive characteristics of the IDEFICS/I.Family study population for reference percentiles of serum ferritin and transferrin, stratified by examination wave (W0: 2007/2008; W3:2013/2014) and sex

Variable W0 (2007/2008) and W3 (2013/2014) pooled
W0 (2007/2008)
W3 (2013/2014)
N Q25 Median Mean Q75 N Q25 Median Mean Q75 N Q25 Median Mean Q75
All
 Ferritin (μg /L) 3390 22 31 35 43 1354 20 29 34 41 2036 23 32 36 44
 Transferrin (g/L) 3416 2.6 2.8 2.8 3 1360 2.6 2.8 2.8 3 2056 2.6 2.8 2.8 3.1
 Age (y) 3417 7.2 9.9 9.62 12.8 1361 4.5 6.4 6.12 7.7 2056 10.4 12.1 11.94 13.6
 BMI z-score 3417 −0.4 0.3 0.4 1.1 1361 −0.5 0.1 0.2 0.9 2056 −0.3 0.4 0.5 1.2
 CRP1 (mg/L) 3183 1.9 2.86 16.52 9.52 1343 1.9 2.86 13.79 9.52 1840 0.94 2.88 18.51 10.14
Boys
 Ferritin (μg/L) 1755 22 30 35.7 42 686 19 27.5 32.85 39 1069 23 32 37.53 44
 Transferrin (g/L) 1760 2.6 2.8 2.85 3.1 688 2.6 2.8 2.85 3.1 1072 2.6 2.8 2.85 3.1
 Age (y) 1761 7.3 9.9 9.63 12.7 689 4.4 6.3 6.08 7.7 1072 10.4 12.1 11.92 13.6
 BMI z-score 1761 −0.43 0.3 0.36 1.07 689 −0.58 0.09 0.15 0.84 1072 −0.3 0.47 0.49 1.25
 CRP1 (mg/L) 1652 1.9 2.86 15.44 9.52 682 1.9 2.86 12.74 7.62 970 1 2.9 17.34 10.82
Girls
 Ferritin (μg/L) 1635 22 31 35.03 43 668 22 30 34.99 42 967 22 31 35.05 43
 Transferrin (g/L) 1656 2.6 2.8 2.82 3 672 2.6 2.8 2.78 3 984 2.6 2.8 2.85 3.1
 Age (y) 1656 7.1 9.85 9.6 12.8 672 4.5 6.5 6.16 7.8 984 10.4 12.2 11.95 13.6
 BMI z-score 1656 −0.39 0.29 0.35 1.07 672 −0.46 0.15 0.23 0.88 984 −0.31 0.42 0.43 1.19
 CRP1 (mg/L) 1531 1.9 3.5 17.68 10 661 1.9 3.81 14.88 10.48 870 0.88 2.88 19.8 9.44

Abbreviations: IDEFICS, Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants; W0, first examination wave; W3, third examination wave.

1

The conversion factor from (mg/L) to unit (μg/mL) is 1; to convert to (mg/dL) divide by 10; to calculate (nmol/L) multiply by factor 9.52.